ARMY MODEL UH-1H/V HELICOPTERS. OPERATOR’S MANUAL (1988)

TM 55-1520-210-10

7-8. General Conditions. In addition to the specific

which data are not provided, thereby increasing the

conditions, the following general conditions are

accuracy of performance predictions.

applicable to the performance data.

7-10. Definitions of Abbreviations.

a. Rigging. All airframe and engine controls are

assumed to be rigged within allowable tolerances.

a Unless otherwise indicated abbreviations and

symbols used in this manual conform to those

b. Pilot Technique.

Normal pilot technique is

established in Military Standard MIL-ST12, which is

assumed. Control movements should be smooth and

periodically revised to reflect current changes in

continuous.

abbreviations usage.

c. Helicopter Variation. Variation in performance

between individual helicopters are known to exist;

b. Capitalization and punctuation of abbreviations

however, they are considered to be small and cannot be

varies, depending upon the context m which they are

individually accounted for.

used. In general, lower case abbreviations are used in

text material, whereas abbreviations used in charts and

d. Instrument Variation. The data shown in the

illustrations appears in full capital letters. Periods do not

performance charts do not account for instrument

usually follow abbreviations; however, periods are used

inaccuracies or malfunctions.

with abbreviations that could be mistaken for whole

words if the period were omitted.

e. Types of Fuel. All flight performance data is

based on IP4 fuel. The change in fuel flow and torque

7-11. Temperature Conversion. The temperature

available, when using JP-5, JP-8, aviation gasoline or

conversion chart Figure 7-1 is arranged so that degrees

any other approved fuels, is insignificant.

Celsius can be converted quickly and easily by reading

Celsius and looking directly across the charts for

7-9. Performance Discrepancies. Regular use of this

Fahrenheit equivalence and vice versa.

chapter will allow you to monitor instruments and other

helicopter systems for malfunction, by comparing actual

performance with planned performance. Knowledge will

also be gained concerning the effects of variable for

Section II TORQUE AVAILABLE

7-12. Description. The torque available charts show

or from the engine acceptance records, is the indicated

the effects of altitude and temperature on engine torque.

torque pressure at 1125 ft-lbs actual output shaft torque,

and is used to correct the error of individual engine

7-13. Chart Differences. Both pressure altitude and

torque indicating system.

FAT affect engine power production. Figure 7-2 shows

power available data at 30 minute power ratings in terms

NOTE

of the allowable torque as recorded by the torquemeter

Torque available values determined

(psi). Note that the power output capability of the T53-L-

are not limits. Any torque which can

13 engine can exceed the transmission structural limit

be achieved, without exceeding

(50 psi calibrated) under certain conditions.

engine, transmission, or other limits,

may be used

a. Figure 7-2 is applicable for maximum power, 30

minute operation at 324 rotor/6600 engine rpm.

7-15. Conditions. Chart (Figure 7-2) is based upon

speeds of 324 rotor/6600 engine rpm grade J-4 fuel.

b. If the IR Scoup Suppressor is installed, subtract

The use of aviation gasoline will not influence engine

one psi from the torque values obtained from Figure 7-2.

power. All torque available are presented for bleed air

heater and device off. Decrease power available 1.4 psi

7-14. Use of Chart The primary use of the chart is

for heater on and 2.1 psi for device on; decrease torque

illustrated by the examples. In general, to determine the

available 3.5 psi if both bleed air heater and device are

maximum power available, it is necessary to know the

operating.

pressure altitude and temperature. The calibration factor

(Data Plate Torque), obtained from the engine data plate

Change 17

7-3

TM 55-1520-210-10

Section III HOVER

7-16. Description. The hover charts (Figure 7-3,

7-19. Conditions

Sheets I and 2) shows the hover ceiling and the torque

required to hover respectively at various pressure

a. The hover charts are based upon calm wind

altitudes, ambient temperatures, gross weights, and skid

conditions, a level ground surface, and the use of 324

heights. Maximum skid height for hover can also be

rotor rpm.

obtained by using the torque available from Figure 7-2.

b. Use of control margin charts Is to determine If

7-17. Use of Chart. The primary use of the hover

adequate control margin will be available for IGE and

charts is illustrated by the charts examples. In general,

OGE hover in winds or low speed translation.

to determine the hover ceiling or the torque required to

hover, it is necessary to know the pressure altitude,

c. The hover charts do not account for the effect of

temperature, gross weight and the desired skid height.

an IR suppressor device. The hover ceiling chart (Figure

In addition to Its primary use, the hover chart (Sheet 2)

7-3, Sheet 1) is not usable if a suppressor device is

can also be used to determine the predicted maximum

installed. The IR Scoup Suppressor creates a download

hover height, which is needed for use of the takeoff chart

of approximately 140 pounds.

(Figure 7-5).

d. For the IR Scoup Suppressor

7-18. Control Margin.

(1) To determine hover torque required, enter

a. Sheet 1 of the control margin charts (Figure 7-4)

the hover power required chart (Figure 7-3, Sheet 2) at a

shows the maximum right crosswind which one can

gross weight of 140 pounds heavier than the actual

achieve and still maintain directional control as a function

gross weight.

of pressure altitude, temperature, and gross weight.

Sheet 2 of the control margin chart (Figure 7-4) shows

(2) To determine predicted maximum hover

the combinations of relative wind velocity and azimuth

height, first subtract one psi from power available (Figure

which may result in marginal directional or longitudinal

7-2); then increase the hover gross weight by

140

control.

pounds. Use this power available and gross weight m

the hover power required chart (Figure 7-3, Sheet 2).

b. Use of the control margin charts is Illustrated by

example on Sheet 1. Ten percent of total control travel

(3) To determine maximum gross weight, first

(full right to full left) is considered adequate margin when

subtract one psi from power available (Figure 7-2), then

hovering. The shaded area on Sheet

1 indicates

decrease the hover gross weight determined from the

conditions where the directional control margin may be

hover power required chart (Figure 7-3, Sheet 2) by 140

less than ten percent m zero wind hover. The shaded

pounds.

area on sheet

2 labeled DIRECTIONAL indicates

conditions where the directional control margin may be

e. With the rotor blade erosion protection coating

less than ten percent for crosswind components in

and polyurethane tape installed, it will be necessary to

excess of those determined from Sheet 1. The shaded

make the following corrections. Add 1 psi to the hover

area on sheet 2 labeled LONGITUDINAL indicates wind

torque required, for OGE and IGE, as determined from

conditions where longitudinal control may be less than 10

Figure 7-3 (Sheet 2). In Figure 7-3 (Sheet 1). subtract

percent. These charts are based on control margin only.

100 pounds from the maximum gross weight to hover

When determining maximum hover wheel height, enter

the chart at the gross weight plus 100 pounds.

Change 17

7-4

TM 55-1520-210-10

Section IV. TAKEOFF

7-20. Description. The takeoff chart (Figure 7-5)

7-21. Use of Charts. The primary use of these charts is

shows the distances to clear various obstacle heights,

illustrated by the charts examples.

The main

based upon several hover height capabilities. The upper

consideration for takeoff performance is the hovering

chart grid presents data for climbout at a constant

skid height capability, which includes the effects of

INDICATED airspeed. The two lower grids present data

pressure altitude, free air temperature, gross weight, and

for climbouts at various TRUE airspeeds. Figure 7-5,

torque. Hover height capability is determined by use of

sheet 1, is based upon level acceleration technique,

the hover chart, Figure 7-3. A hover check can be made

sheet 2 is based upon a climb and acceleration from a 3

to verify the hover capability. If winds are present, the

foot skid height and sheet 3 is based upon a level

hover check may disclose that the helicopter can actually

acceleration from-a 15 foot skid height.

hover at a greater skid height than the calculated value,

since the hover chart is based upon calm wind

NOTE

conditions.

The hover heights shown on the

chart are only a measure of the

7-22. Conditions.

aircraft’s climb capability and do not

imply that a higher than normal hover

a. Wind. The takeoff chart is based upon calm

height should be used during the

wind conditions. Since surface wind velocity and

direction cannot be accurately predicted, all takeoff

actual takeoff.

planning should be based upon calm wind conditions.

Takeoff into any prevailing wind will improve the takeoff

performance.

b. Power Settings. All takeoff performance data

are based upon the torque used m determining the hover

capabilities in Figure 7-3.

Change 17

7-4.1/(7-4.2 blank)

TM 55-1520-210-10

Section V. CRUISE

7-23.

Description. The cruise charts (Figure 7-6

and PSI torque pressure. For conservatism, use the

sheets 1 through 24) show the torque pressure and

gross weight at the beginning of cruise flight. For greater

engine rpm required for level flight at various pressure

accuracy on long flights It is preferable to determine

altitudes airspeeds gross weights and fuel flows.

cruise information for several flight segments in order to

allow for decreasing fuel weights (reduced gross weight).

NOTE

Estimated performance data is presented for hover

The cruise charts are basically

(KTAS-O) in Figure 7-6, however, the hover performance

arranged by FAT groupings. Figure

data presented in figure 7-3 is more accurate and should

7-6, sheets 1 through 24 are based

be used in planning critical hover performance. The

following parameters contained in each chart are further

upon

operation

with

clean

explained as follows:

configuration.

Each chart has a

dashed line that represents a ten

a. Airspeed. True and indicated airspeeds are

square foot equivalent flat plate

presented at opposite sides of each chart. On any chart,

drag area This allows quick

indicated airspeed can be directly converted to true

determination of Delta PSI for other

airspeed (or vice versa) by reading directly across the

than clean configurations.

chart without regard for other chart information.

Maximum permissible airspeed (VNE) limits appear on

7-24. Use of Charts.

some charts. If no line appears VNE is above the limits

of the chart.

Cruise flight is restricted to 319 to

b. Torque Pressure (PSI). Since pressure altitude

324 Cruise flight is restricted to 319

and temperature are fixed for each chart torque

324 Rotor RPM

(6500 to

6600

pressures vary according to gross weight, airspeed and

Engine RPM.).

Cruise at

324

bleed air on or off. See paragraph 7-15 for effect of

Rotor/6600

Engine

RPM

bleed air heater and device.

recommended. The cruise chart data

for true airspeeds above 40 KTAS is

NOTE

based on

314 Rotor/6400 Engine

Torque available values determined are

RPM. Until the cruise charts are

not limits. Any torque which can be

revised performance planning shall

achieved without exceeding engine

accomplished

using

the

transmission or other limits may be

procedures and torque corrections

used.

from Table 7-1. These restrictions do

not apply when composite main rotor

c. Fuel Flow. Fuel flow scales are provided opposite the

blades (CB) are installed.

torque pressure scales. On any chart, torque pressure

may be converted directly to fuel flow without regard for

The primary use of the charts is illustrated by the

other chart information. All fuel flows are presented for

bleed air heater and device off. Add two percent fuel

examples provided in Figure 7-6. The first step for chart

use is to select the proper chart, based upon the planned

flow (about 14 lb/hr) for heater on and increase fuel flow

three percent (approximately 21 lb/hr) for device on. If

drags configuration, pressure altitude and anticipated

free air temperature; refer to Chapter 7 index (paragraph

both are operating, add five percent fuel flow (about 35

7-2). Normally, sufficient accuracy can be obtained by

lb/hr) to chart values.

selecting the chart nearest to the planned cruising

altitude and FAT, or the next higher altitude and FAT. If

d. Maximum Range. The maximum range lines indicate

the combinations of weight and airspeed that will

greater accuracy is required, interpolation between

altitudes and/or temperatures will be required. You may

produce the greatest flight range per gallon of fuel under

enter the charts on any side: TAS, IAS, torque pressure,

zero wind conditions. When a maximum range condition

or fuel flow, and then move vertically or horizontally to

does not appear on a chart it is because the maximum

the gross weight, then to the other three parameters.

range speed is beyond the maximum permissible speed

(VNE); m such cases, use VNE cruising speed to obtain

Maximum performance conditions are determined by

entering the chart where the maximum range or

maximum range.

maximum endurance and rate of climb lines intersect the

appropriate gross weight; then read airspeed, fuel flow

Change 17

7-5

TM 55-1520-210-10

e. Maximum Endurance and Rate of Climb. The

7-25. Conditions. The cruise charts are based upon

maximum endurance and rate of climb lines indicate the

operations at 324 rotor / 6600 engine rpm below 40

airspeed for minimum torque pressure required to

KTAS and 314 rotor/6400 engine rpm for true airspeeds

maintain level flight for each gross weight FAT and

above 40 knots. With the rotor blade erosion protection

pressure altitude. Since minimum torque pressure will

coating and polyurethane tape installed, add 2 psi to the

provide minimum fuel flow maximum flight endurance will

torque required obtained from Figure 7-6.

be obtained at the airspeeds indicated.

Section VI. DRAG

7-26. Description. The drag chart (Figure 7-7, Sheet 1

temperature. Enter at the known drag area change,

2) shows the authorized configuration or the

move right to TAS move down to pressure altitude move

equivalent flat plate drag area changes for additional

left to FAT then move down and read change in torque.

aircraft modifications. There is no increase in drag with

In addition, by entering the chart in the opposite direction,

cargo doors fully open. The upper left portion of Figure

drag area change may be found from a known torque

7-7 (Sheet 2 of 2) presents drag areas of typical external

change. This chart is used to adjust cruise charts for

loads as a function of the load frontal area. The balance

appropriate torque and fuel flow due to equivalent flat

of the charts shows the additional torque required in level

plate drag area change (AF).

For frontal areas

flight due to the increase in drag caused by external

exceeding values shown on Figure 7-7 (Sheet 2 of 2)

loads, aircraft modifications or authorized configurations.

use a smaller value and multiply (e.g 36 sq. ft. 9 sq ft. x

The IR Scoup Suppressor has a drag of two square feet.

4).

7-27. Use of Chart. The primary use of the chart is

7-28. Conditions. The drag chart is based upon 314

illustrated by the example. To determine the change in

rotor/6400 engine rpm.

torque it is necessary to know the drag area change the

true airspeed the pressure altitude and the free air

Section VII. CL MB-DESCENT

7-29. Description.

b. By entering the bottom of the grid with a known_

torque change, moving upward to the gross weight, and

The climb descent chart (Figure 7-8) shows the

left to the corresponding rate of climb or descent may

change in torque (above or below torque required for

also be obtained.

level flight under the same gross weight and atmospheric

conditions) to obtain a given rate of climb or descent.

7-31. Conditions.

7-30. Use of Chart.

Climb-Descent The climb-descent chart is based

on the use of constant rotor or engine rpm. The rate of

Climb-Descent The primary uses of the chart are

climb (descent) presented is for steady state conditions

illustrated by the chart examples.

and rpm bleed could increase (decrease) the rate of

climb (descent) shown.

a. The torque change obtained from the grid scale

must be added to the torque required for level flight (for

climb) or subtracted from the torque required for level

flight (for descent)-obtained from the appropriate cruise

chart in order to obtain a total climb or descent torque.

Change 17

7-6

TM 55-1520-210-10

Section VIII. FUEL FLOW

7-32.

Description

b. Fuel flow will increase about two percent with

the bleed air heater on and three percent with deice

a. The fuel flow chart (fig 7-9) shows the fuel flow

on. When both systems are on, increase fuel flow

at engine idle and 324 rotor/6600 engine rpm with

five percent. Also a range or endurance penalty

flat pitch.

should be accounted for when working cruise chart

data. A fairly accurate rule-of-thumb to correct fuel

b. Fuel flow vs torque, shows fuel flow in pound-

flow for temperatures other than

0^oC FAT is to in-

per-hour versus torquemeter psi for pressure

crease (decrease) fuel flow 1 percent for each 10^oC

altitudes from sea level to 14000 feet and for 0°C

increase (decrease) in FAT.

free air temperature.

7-34. Conditions

7-33. Use of Chart

These charts are based upon the use of JP-4 fuel. The

a. The primary use of the idle fuel flow chart is il-

change in fuel flow when using other jet fuels is in-

lustrated by the example. To determine the idle fuel

significant.

flow, it is necessary to know the idle condition,

pressure altitude, and free air temperature. Enter at

the pressure altitude, move right to FAT in ap-

propriate grid, then move down and read fuel flow

on the scale corresponding to the condition. Refer to

the cruise charts to obtain fuel flow for cruise power

conditions.

Change 2

7-7

TM 55-1520-210-10

Table

7-1 Torque Correction (Sheet

1 of

To determine cruise performance data for 324 Rotor/6600 Engine

RPM at speeds above 40 KTAS, follow the instructions in paragraph

7-24 except:

Add appropriate torque correction from this table to the

calibrated torque required values determined from the intersection

of the airspeed and gross weight lines on the upper (6400 Engine

RPM) portion of the cruise chart.

b. Determine fuel flow corresponding to the corrected torque

required from the lower (6600 Engine RPM) portion of the cruise

chart.

Determine continuous torque available (CONT TRQ AVAIL) and

30 minute torque available (30 MIN TRQ AVAIL) from the lower

(6600 Engine RPM) portion of the cruise chart.

EXAMPLE

WANTED

Speed for Maximum Range

Calibrate Torque Required and Fuel Flow at Maximum Range

KNOWN

324 Rotor/6600 Engine RPM

Clean Configuration

FAT = -30°C

Pressure Altitude = 8000 feet

Gross Weight = 8500 pounds

Roof Mounted System

METHOD

Locate (-30°C FAT, 8000 Feet) Chart (figure 7-6 Sheet 3 of

24)

Find Intersection of 8500 LB Gr Wt Line With the Max Range Line

Read Speed for Maximum Range:

Move Right, Read TAS = 105.3 Knot

Move Left, Read IAS = 102.3

Read Calibrated Torque Required @ 314 Rotor/6400 Engine RPM

Move Down, Read Torque = 41.2 PSI

Correct Torque Required for 6600 Engine RPM

From Table for Sheet 3 (8000 Ft -30°C) @ 8500 Lb Gross Weight

For 90 KTAS, Torque Correction = 3.5 PSI

For 110 KTAS, Torque Correction = 5.7 PSI

Interpolate for 105.3 KTAS

Torque Correction = 5.2 PSI

Corrected Torque Required = 41.2 PSI + 5.2 PSI = 46.4 PSI

To Determine Fuel Flow

Enter Figure

7-6, Sheet 3 of 24 At 46.4 PSI Torque:

Move Down Read Fuel Flow = 614 Lb/Hr

7-8

TM 55-1520-210-10

TABLE 7-1 TORQUE CORRECTION

(Sheet 2 of

TORQUE CORRECTION - PSI

(-30°C FAT)

SHEET 1

SHEET 2

SHEET 3

SHEET 4

GW-LB

KTAS

2000

4000

6000

8000

10000

12000

14000

5500

2.4

2.2

2.1

1.9

1.8

2.8

2.6

2.4

2.2

3.5

3.4

3.2

3.0

2.9

110

5.9

5.5

5.2

4.9

4.5

6500

3.0

2.8

2.6

2.4

2.2

2.1

1.9

3.3

3.2

3.1

2.9

2.6

2.5

2.4

2.3

4.3

4.1

3.9

3.7

3.5

3.4

2.9

110

7.3

6.9

6.4

6.1

5.6

5.3

4.5

4.6

7500

3.1

2.9

2.6

2.5

2.3

1.7

1.4

3.5

3.3

3.0

2.8

2.7

2.2

4.5

4.3

4.1

3.9

3.4

3.3

2.9

2.7

110

7.4

7.0

6.5

6.2

5.3

4.7

8500

3.0

2.9

2.7

2.6

2.3

1.8

1.1

0.8

3.5

3.4

3.3

3.1

2.8

2.6

1.8

1.1

4.6

4.4

4.0

3.7

3.5

3.2

1.9

0.8

110

7.5

7.1

6.4

6.0

5.7

5.5

2.6

0.6

9500

3.1

3.0

2.9

2.1

1.7

1.1

0.1

-1.8

3.8

3.5

3.4

2.8

1.9

-0.6

-2.3

4.9

4.2

3.5

2.0

-2.4

-1.5

110

7.7

6.6

6.7

6.0

5.9

2.5

-4.8

1.4

[-15°C FAT]

SHEET 5

SHEET 6

SHEET 7

SHEET 8

GW-LB

KTAS

2000

4000

6000

8000

10000

12000

14000

5500

1.3

1.2

1.1

1.0

1.9

1.7

1.5

1.3

2.6

2.5

2.3

2.2

2.1

1.9

110

3.0

2.9

2.6

2.4

2.3

2.0

6500

1.5

1.4

1.3

1.2

1.1

1.0

0.5

2.2

2.1

1.9

1.7

1.6

1.5

1.3

3.0

2.9

2.7

2.5

2.4

2.2

2.1

1.8

110

3.5

3.3

3.1

2.8

2.7

2.3

2.2

1.8

7500

1.6

1.4

1.3

1.2

0.7

0.3

2.2

2.0

1.9

1.8

1.6

0.6

3.2

2.9

2.8

2.6

2.4

2.1

2.0

0.9

110

3.6

3.3

3.2

2.7

2.5

2.2

2.1

-0.5

8500

1.6

1.5

1.4

1.1

0.7

0.5

-0.9

2.3

2.2

2.1

1.9

1.7

1.2

0.8

-1.4

3.3

3.1

2.8

2.6

2.2

1.6

1.3

-3.2

110

3.6

3.3

2.8

2.7

2.3

0.8

-0.2

-7.5

9500

1.6

1.4

0.8

0.9

0.4

-0.1

-0.8

-7.5

2.3

2.0

0.8

-0.2

-1.2

-6.6

3.2

3.1

2.6

1.2

-0.8

-2.9

-6.8

110

3.2

3.1

2.7

-0.7

-3.8

-7.2

-6.9

7-9

TM 55-1520-210-10

TABLE 7-1 TORQUE CORRECTION

(Sheet 3 of

TORQUE CORRECTION - PSI

[O°C FAT]

SHEET 9

SHEET 10

SHEET 11

SHEET 12

GW-LB

KTAS

2000

4000

6000

8000

10000

12000

14000

5500

1.1

1.0

0.9

0.8

1.2

1.1

1.0

0.9

0.8

9 0

1.4

1.3

1.2

1.1

1.0

110

2.5

2.3

2.1

2.0

1.9

1.6

6500

1.4

1.3

1.1

1.2

1.1

0.9

0.7

0.6

1.4

1.3

1.2

1.1

0.9

0.8

1.6

1.5

1.4

1.2

0.9

110

2.9

2.7

2.5

2.4

2.1

2.0

1.8

1.6

7500

1.3

1.2

1.1

0.9

0.7

0.4

1.4

1.3

1.1

1.0

0.8

0.2

0.0

1.6

1.4

1.3

1.2

0.9

0.3

0.0

110

3.0

2.7

2.5

2.3

2.1

1.9

0.5

-0.1

8500

1.4

1.3

1.1

0.7

0.4

-0.5

-3.0

1.5

1.3

1.2

0.9

0.8

0.1

-1.5

-3.8

1.7

1.5

1.0

0.8

0.1

-3.8

-5.9

110

3.0

2.5

2.1

1.8

0.0

-4.9

-8.8

9500

1.3

1.0

0.8

0.5

0.4

-0.8

-6.9

1.4

1.2

1.1

0.3

0.0

-2.0

-7.3

1.6

1.3

1.2

0.3

-0.3

-5.3

-8.5

110

2.8

2.6

2.4

0.4

-0.4

-6.3

-15.4

(15°C FAT)

SHEET 13

SHEET 14

SHEET 15

SHEET 16

GW-LB

KTAS

2000

4000

6000

8000

10000

12000

14000

5500

0.7

0.6

0.7

0.6

0.5

0.9

0.8

0.7

0.6

0.5

1.0

1.1

0.9

0.8

0.7

110

0.9

0.8

6500

0.8

0.7

0.8

0.7

0.6

0.4

0.2

1.0

0.9

0.6

0.5

0.4

0.1

1.2

1.1

1.0

0.9

0.8

0.6

0.3

110

1.1

1.0

0.9

0.8

0.6

-0.3

7500

0.9

0.8

0.7

0.4

0.1

-1.0

1.1

1.0

0.7

0.5

0.2

-0.2

-1.7

1.2

1.1

1.0

0.6

0.5

-0.1

-4.2

110

1.1

1.0

0.9

1.1

0.7

0.1

-1.2

-6.7

8500

0.9

0.8

0.6

0.5

0.0

-0.5

-1.3

-7.3

0.9

0.8

0.6

0.5

-0.3

-0.9

-2.0

-7.1

1.1

1.2

0.8

-0.1

-2.0

-5.0

-7.9

110

1.0

1.1

0.8

-1.5

-4.0

-8.2

-19.6

9500

0.8

0.6

0.4

0.0

-1.4

-4.9

0.7

0.6

0.2

-0.2

-2.2

-5.2

1.2

0.8

0.4

0.0

-5.4

-7.3

110

1.2

0.9

-0.2

-1.5

-8.7

-15.2

7-10

TM 55-1520-210-10

TABLE 7-1 TORQUE CORRECTION

(Sheet 4 of

TORQUE CORRECTION - PSI

[30°CFAT]

SHEET 17

SHEET 18

SHEET 19

SHEET 20

GW-LB

KTAS

2000

4000

6000

8000

10000

12000

14000

5500

0.5

0.6

0.5

0.3

0.8

0.7

0.6

0.5

0.3

0.5

0.4

0.3

0.2

0.3

0.1

110

0.8

0.7

0.6

6500

0.6

0.7

0.5

0.3

0.4

0.0

0.7

0.6

0.5

0.4

0.3

-0.2

0.6

0.4

0.3

0.4

0.1

-0.6

110

1.0

0.9

0.8

1.0

0.6

0.5

-0.9

7500

0.9

0.7

0.6

0.5

0.4

-0.1

-0.6

-1.6

0.8

0.5

0.4

0.3

-0.3

-0.9

-2.0

0.3

0.4

0.1

0.2

-0.7

-2.7

-5.1

110

0.9

1.0

0.8

0.7

-1.1

-2.8

-7.4

8500

0.7

0.6

0.5

0.1

0.0

-1.6

-6.3

0.5

0.4

0.0

-0.1

-2.1

-6.0

0.4

0.3

0.2

-0.4

-0.7

-5.7

-7.9

110

1.2

1.0

0.7

-0.6

-1.1

-8.0

-16.3

9500

0.5

-0.1

-1.0

-2.2

-8.3

0.4

0.5

-0.3

-1.3

-2.7

-7.7

0.1

0.2

-0.8

-3.9

-6.6

-9.3

-1.3

110

0.8

-5.4

-9.7

-21.5

[45°C FAT]

SHEET 21

SHEET 22

SHEET 23

SHEET 24

GW-LB

KTAS

2000

4000

6000

8000

10000

12000

14000

5500

0.5

0.6

0.5

0.4

0.3

0.2

0.4

0.5

0.4

0.3

0.1

0.2

0.1

0.5

0.3

0.2

0.3

0.1

110

0.3

0.4

0.3

0.0

6500

0.6

0.5

0.4

0.3

0.2

-0.1

-0.3

0.5

0.4

0.3

0.2

0.1

-0.3

-0.6

0.3

0.2

0.4

0.3

0.1

-0.4

-1.3

110

0.3

0.4

0.3

0.0

-1.1

-2.5

7500

0.6

0.4

0.3

0.0

-0.1

-1.5

-5.9

0.3

0.2

0.3

0.2

-0.2

-2.1

-5.7

0.3

0.4

0.1

-0.4

-0.6

-5.0

-6.9

110

0.4

0.5

0.3

0.0

-0.9

-1.5

-7.9

-14.7

8500

0.5

0.3

0.2

-0.2

-1.4

-3.6

7.2

0.3

0.2

0.1

-0.3

-1.9

-3.9

8.0

0.5

0.1

0.0

-0.8

-4.4

-6.4

11.0

110

0.6

0.0

-0.3

-1.8

-7.2

-11.7

9500

0.4

-0.1

-0.4

-1.9

-7.7

0.2

-0.4

-0.6

-2.6

-7.5

0.3

-0.7

-1.4

-6.3

-8.8

110

0.1

-1.6

-2.8

-10.0

-18.8

7-11

TM 55-1520-210-10

Chapter 8

Normal Procedures

Section 1. MISSION PLANNING

8-1. Mission Planning. Mission planning begins when

prescribed in Chapter

5 OPERATING LIMITS AND

the mission is assigned and extends to the preflight

RESTRICTIONS.

check of the helicopter. It includes but is not limited to

checks of operating limits and restrictions; weight

8-4.

Performance.

Refer to chapter

7 or 7.1

balance and loading; performance; publication; flight plan

PERFORMANCE DATA to determine the capability of

and crew and passenger briefings. The pilot in

the helicopter for the entire mission. Consideration shall

command shall ensure compliance with the contents of

be given to changes in performance resulting from

this manual that are applicable to the mission.

variation in loads temperatures and pressure altitudes.

Record the data on the Performance Planning Card for

8-2.

Operating Limits and Restrictions.

The

use in completing the flight plan and for reference

minimum maximum normal and cautionary operational

throughout the mission.

ranges represent careful aerodynamic and structural

calculation substantiated by flight test data.

These

8-5. Crew and Passenger Briefings. A crew

limitations shall be adhered to during all phases of the

briefing shall be conducted to ensure a thorough

mission. Refer to chapter 5 OPERATING LIMITS AND

understanding of individual and team responsibilities.

RESTRICTIONS for detailed information.

The briefing should include but not be limited to copilot

crew chief mission equipment operator, and ground crew

8-3. Weight Balance and Loading. The helicopter

responsibilities and the coordination necessary to

shall be loaded cargo and passengers secured and

complete the mission In the most efficient manner. A

weight and balance verified in accordance with

review of visual signals Is desirable when ground guides

chapter 6 WEIGHT BALANCE AND LOADING. This

do not have direct voice communications link with the

helicopter requires a weight and balance clearance in

crew.

accordance with AR 95-1. The helicopter weight and

center-of-gravity conditions shall be within the limits

Section 11. CREW DUTIES

86. Crew Duties.

e. Passenger Briefing. The following is an outline

that should be used in accomplishing required passenger

a. Responsibilities. The minimum crew required to

briefings. Items that do not pertain to a specific mission

fly the helicopter is a pilot. Additional crewmembers as

may be omitted.

required may be added at the discretion of the

commander. The manner in which each crewmember

(1) Crew Introduction.

performs his related duties is the responsibility of the

pilot in command.

(2) Equipment.

b. Pilot. The pilot in command is responsible for all

(a) Personal to include ID tags.

aspects of mission planning preflight and operation of the

helicopter. He will assign duties and functions to all

other crewmembers as required. Prior to or during

(b) Professional.

preflight the pilot will brief the crew on the mission

performance data procedures taxi and load operations.

c. Copilot (when assigned). The copilot must be

familiar with the pilots duties and the duties of the other

(3) Flight Data.

crew positions.

The copilot will assist the pilot as

directed.

(a) Route.

d. Crew Chief (when assigned). The crew chief will

perform all duties as assigned by the pilot.

Change 17

8-1

TM 55-1520-210-10

(b) Altitude.

(i)

Refueling.

(j)

Weapons.

(d) Weather.

(k)

Protective masks.

(4) Normal Procedures.

(l)

Parachutes.

(a) Entry and exit of helicopter.

(m) Ear protection.

(b) Seating.

(n)

ALSE.

(c)

Seat belts.

(5) Emergency procedures.

(d)

Movement m helicopter.

(a)

Emergency exits.

(e)

Internal communications.

(b)

Emergency equipment.

(f)

Security of equipment.

(c)

Emergency landing/ditching procedures.

(g)

Smoking.

8-7. Danger Areas. Refer to Figure -1.

(h) Oxygen.

Section III. OPERATING PREDURES AND MANEUVERS

8-8. Operating Procedures and Maneuvers. This

covered in Section Vl, ADVERSE ENVIRONMENTAL

section deals with normal procedures and includes all

CONDITIONS.

steps necessary to ensure safe and efficient operating of

the helicopter from the time a preflight begins until the

8-10. Checklist. Normal procedures are given primarily

flight is completed and the helicopter is parked and

in checklist form and amplified as necessary in

secured. Unique feel, characteristics and reaction of the

accompanying paragraph form when a detailed

helicopter during various phases of operation and the

description of a procedure or maneuver is required. A

techniques and procedures used for taxiing, takeoff,

condensed version of the amplified checklist omitting all

climb, etc., are described including precautions to be

explanatory text is contained in the Operator’s Checklist

observed.

Your flying experience is recognized;

TM 55-1520210-CL. To provide for easier cross-

therefore basic flight principles are avoided. Only the

referencing the procedural steps in CL are numbered to

duties of the minimum crew necessary for the actual

coincide with the corresponding numbered steps in this

operation of the helicopter are included

manual.

8-9. Additional Crew. Additional crew duties are

8-11. Checks. The checklist may include items for day,

covered as necessary in Section II, CREW DUTlES.

night, and instrument flight with annotative indicators

Mission equipment checks are contained in Chapter 4,

immediately preceding the check to which they are

MISSION EQUIPMENT. Procedures specifically related

pertinent; N for night operation only; I for instrument

to instrument flight that are different from normal

operations only; and 0 to indicate a requirement if the

procedures are covered in this section following normal

equipment is installed When a helicopter is flown on a

procedures. Descriptions of functions operations and

mission requiring intermediate stops it is not necessary

effects of controls are covered in Section V, FLIGHT

to perform all of the normal checks. The steps that are

CHARACTERISTICS and a repeated in this section only

C essential for safe helicopter operations on intermediate

when required for emphasis. Checks that must be

stops are designated as "thru-flight" checks. An asterisk

performed under adverse environmental conditions such

(*) indicates that performance of steps is mandatory for

as desert and cold weather operations supplement

all "thru-flights". The asterisk (-) applies only to checks

normal procedure checks in this section and are

performed prior to takeoff..

Change 17

8-2

TM 55-1520-210-10

Cabin top - Check windshields, wipers, FAT

WARNING

probe, WSPS, for condition.

Do not preflight until armament

systems are safe.

Radio compartment - Check security of all

equipment. Check battery, If installed. Secure door.

812. Before Exterior Checks.

Antennas - Check condition and security.

1. Covers, locking devices, tiedowns, and cables

Removed, except aft main rotor tiedown.

Pitot tube

Check security and

unobstructed.

2. Publications - Check in accordance with DA

PAM

738-751 and locally required forms and

Cabin lower area

- Check condition of

publications.

windshield, antennas, WSPS and fuselage. Check for

loose objects inside winch might Jam controls.

3. AC circuit breakers - IN.

Cargo suspension mirror - Check security

BAT switch ON. Check battery voltage. A

and cover installed. Uncover and adjust if cargo

minimum of 24 volts should be indicated on the DC

operations are anticipated.

voltmeter for a battery start.

8-15. Area 2.

Lights--ON. Check landing, search, anti-

collision, position, interior lights and NVG lighting as

1. Fuselage - Check as follows:

required for condition and operation as required; position

Static port - Check unobstructed.

landing and search lights as desired; then OFF.

b. Copilot seat, seat belt and shoulder harness

6. Fuel - Check quantity. Caps secure.

- Check condition and security; secure belt and harness

if seat is not used during flight.

Fuel sample Check for contamination

Copilot door

Check condition and

before first flight of the day. If the fuel sumps, and filter

security.

have not been drained by maintenance personnel, dram

a sample as follows:

Cabin doors - Check condition and security.

a. Sumps - Drain sample and check.

Landing gear

- Check condition and

b. MAIN FUEL switch - ON.

security; ground handling wheels removed.

Filter - Dram sample and check.

Auxiliary fuel tanks - Drain sample and

Radio and electrical compartments - Check

check

condition, circuit breakers m and components secure.

e. MAIN FUEL switch - OFF.

Secure access doors.

Cargo hook Check as required, if use is

O* g. Armament systems -Check weapon(s) safe.

anticipated, refer to Chapter 4, MISSION EQUIPMENT,

Check condition and security.Refer to Chapter

for checks of the system.

MISSION EQUIPMENT, for checks of the system.

9. BAT switch - OFF.

2. Engine compartment - Check fluid lines and

connections for condition and security. Check general

10.Flight Controls - Check freedom of movement of

condition. Cowling secure

cyclic and collective; center cyclic, collective down.

816.

Area 3.

8-13. Exterior Check. (Fig 8-2).

1. Tailboom - Check as follows:

Skin - Check condition.

8-14. Area 1.

Driveshaft cover - Check secure.

Synchronized elevator - Check condition

1. Main rotor blade - Check condition.

and security.

d. Antennas - Check condition and security.

2. Fuselage - Check as follows:

e. Tail skid - Check condition and security.

Change 16

TM 55-1520-210-10

2. Tail rotor Check condition and free movement on

8-19.

Area 6.

flapping axis. The tail rotor blades should be checked as

the main rotor blade is rotated. Visually check all

Man rotor system

- Check condition and

components for security.

security; check level of fluid in dampers, blade grips, and

pillow blocks.

3. Main rotor blade - Check condition, rotate in

normal direction

90 degrees to fuselage, tiedown

2. Transmission area - Check as follows:

removed.

Transmission and hydraulic filler caps

8-17.

Area 4.

Secure.

Main driveshaft

- Check condition and

1. Tail rotor gearboxes (90 and 42 degrees) -

security.

Check general condition, oil levels, filler caps secure.

Engme air intake - Check unobstructed.

Engine and transmission cowling - Check

2. Tailboom - Check as follows;

condition and security.

Antennas - Check condition and security.

Skin - Check condition.

Antennas - Check condition and security.

f. Pitot static tube - Check security and unob-

Synchronized elevator - Check condition

structed.

and security

8-2t

Interior Check - Cabin.

3. Engine exhaust/smoke generator

- Check

condition. Refer to Chapter 4, MISSION EQUIPMENT,

1. Transmission oil level - Check.

for systems check.

2. Cabin area - Check as follows:

4. Oil cooling fan and heater compartments

Check condition of fan, flight control and cables, tail rotor

Cargo

- Check as required for proper

servo for leaks and security and battery if installed;

loading and security.

check for installation of structural support; check

tailboom attachment bolts; check heater for condition

Loose equipment

- Stow rotor blade

and security if installed; check area clear of obstructions;

tiedown, pitot tube cover, tailpipe cover and other

secure doors.

equipment.

8-18.

Area 5.

Mission equipment - Check condition and

security. Refer to Chapter 4, MISSION EQUIPMENT, for

1. Engine compartment - Check fluid lines and

equipment checks.

connections for condition and security. Check fluid

levels and general condition; cowling secure.

Passenger seats and belts

- Check

condition and security.

2. Hydraulic fluid sight gage - Check.

First aid kits - Check secure.

3. Fuselage - Check as follows:

Fire extinguisher - Check secure.

Armament systems - Check weapon(s)

safe. Check condition and security. Refer to Chapter-4,

3. Crew and passenger briefing - Complete as

MISSION EQUIPMENT, for systems check.

required

Cabin doors - Check condition and security.

Landing gear

- Check condition and

8-21.

Before Starting Engine.

security; ground handling wheels removed.

Static port -Check unobstructed.

1. Overhead switches and circuit breakers - Set as

Pilot door -Check condition and security.

follows:

Pilot seat, seat belt and shoulder harness -

Check condition and security.

a. Smoke generator operating switch -

Check

condition and security. Refer to Chapter 4, MISSION

Fire extinguisher

Check secure.

EQUIPMENT, for systems check.

8-4

Change 16

TM 55-1520-210-10

b. DC circuit breakers-in, except for armament

0 c. DISP CONTROL panel-Check ARM/STBY/

and special equipment.

SAFE switch is SAFE; check that JETTISON switch is

down and covered.

O c. DOME LT switch-As required.

d. GOV switch-AUTO.

d. PITOT HTR switch-OFF.

e. DE-ICE switch-OFF.

*e. EXT LTS switches-Set as follows:

✩ f. FUEL switches-Set as follows:

(1) ANTI COLL switch-ON.

(1) MAIN FUEL switch-ON.

(2) POSITION lights switches-As required:

O (2) START FUEL switch-ON.

STEADY or FLASH for night; OFF for day.

(3) All other switches-OFF.

f. MISC switches-Set as follows:

g. CAUTION panel lights-TEST and RESET.

(1) CARGO REL switch-OFF.

h. HYD CONT switch-ON.

(2) WIPERS switch-OFF.

i. FORCE TRIM switch-ON.

g. CABIN HEATING switches-OFF.

j. CHIP DET switch-BOTH.

h. INST LTG switches-As required.

8. Flight controls-Check freedom of movement

I. AC POWER switches-Set as follows:

through full travel: center cyclic and pedals; collec-

tive pitch full down.

(1) PHASE switch-AC.

9. Altimeters-Set to field elevation.

(2) INVTR switch-OFF.

✩ 8-22. Starting Engine

j. DC POWER switches-Set as follows:

1. Fireguard-Posted if avaliable.

(1) MAIN GEN switch-ON and cover down.

2. Rotor blades-Check clear and untied.

(2) VM selector-ESS BUS.

3. Ignition key lock switch-On.

(3) NON-ESS BUS switch-As required.

4. Throttle-Set for start. Position the throttle as

near as possible (on decrease side) to the engine

(4) STARTER GEN switch-START.

idle stop.

✩ (5) BAT switch-ON.

5. Engine-Start as follows:

a. Start switch-Press and hold; start time. Note

✩ 2. Ground power unit-Connect for GPU start.

DC voltmeter indication. Battery starts can be made

O 3. Smoke gage-Check.

when voltages less than 24 volts are indicated, pro-

vided the voltage is not below 14 volts when crank-

4. FIRE warning indicator light-Test.

ing through 10 percent N1 speed.

5. Press to test caution/warning lights-Check as

b. Main rotor-Check that the main rotor is turning

required.

as N1 reaches 15 percent. If the rotor is not turning,

abort the start.

6. Systems instruments-Check engine and trans-

O c. START FUEL switch-OFF at 40 percent N1.

mission systems for static indications, slippage

marks, and ranges.

d. Start switch-Release at 40 percent N1 or after

40 seconds, whichever occurs first. Refer to chapter

7. Center pedestal switches-Set as follows:

5 for starter limitations.

a. Avionics equipment-Off; set as desired.

e. Throttle-Slowly advance past the engine idle

stop to the engine idle position. Manually check the

b. External stores jettison handle-Check safetied.

engine idle stop by attempting to close the throttle.

8-5

TM 55-1520-210-10

N168 to

72 percent. Hold a very slight

7. Health Indicator Test (HIT) Check Perform as required.

pressure against the engine idle stop during the check. A

Refer to HIT/EGT Log in helicopter log book. Normal HIT

slight rise in N1 may be anticipated after releasing pressure on

Check not required if utilizing in-flight HIT checks unless

throttle.

engine maintenance has taken place since last return flight.

8-24. Deleted.

8-25. Deleted.

The copilot attitude indicator should be

8-26. Deleted.

caged and held momentarily as inverter

power is applied.

8-27. Deleted.

6. INVTR switch - MAIN ON.

8-28. Hover/Taxi Check. Perform the following checks at a

hover:

7. Engine and transmission oil pressures - Check.

1. Engine and transmission instruments - Check.

8. GPU - Disconnect.

2. Flight Instruments - Check as required.

8-23. Engine Runup.

a. VSI and altimeter Check for indication of climb

1. Avionics - On.

and descent.

2. STARTER GEN switch- STBY GEN.

b. Slip Indicator Check ball free in race.

3. Systems - Check as follows:

c. Turn needle heading indicator and magnetic

compass Check for turn indication left and right.

a. FUEL.

d. Attitude Indicator Check for indication of nose

high and low and banks left and right.

b. Engine.

e. Airspeed Indictor Check airspeed.

c. Transmission.

3. Power Check as required. The power check is

d. Electrical.

performed by comparing the indicated torque required to hover

with the predicted values from performance charts.

(1) AC - 112 to 118 volts.

8-29. Deleted.

(2) DC - 27 volts at 26°C and above.

volts from 0°C to 26°C. 28.5 volts below 0°C.

4. RPM--6600. As throttle is increased, the low rpm

audio and warning light should be off at 6100 to 6300 rpm.

5. Deleted.

6. Avionics and flight instruments Check and set as

required.

NOTE

HIT Checks while operating in adverse

conditions (e.g., dust, desert, coastal beach

area, dry riverbeds) may be deferred

(maximum of 5 flight hours) at the discretion

of the pilot in command until a suitable

location is reached.

Change 17 8-6

TM 55-1520-210-10

8-30.

Before Take-off, Immediately prior to take-

helicopter attitude and collective pitch as required to

or the following checks shall be accomplished.

establish a climb at the desired rate and airspeed.

Continuous coordinated application of control pressures

1. RPM - 6600.

is necessary to maintain trim heading flight path airspeed

and rate of climb. This technique is desirable when OGE

2. Systems - Check engine, transmission, electrical

hover capability exists. Take-off may be made from the

and fuel systems indications.

ground by positioning the cyclic control slightly forward of

neutral prior to increasing collective pitch.

3. Avionics - As required.

Level Acceleration Align the helicopter with

the desired take-off course at a stabilized hover of

4. Crew passengers and mission equipment

approximately three feet (skid height). Apply forward

Check

cyclic pressure smoothly and gradually while

simultaneously increasing collective pitch to begin an

8-31.

Take-off.

acceleration at approximately 3 to 5 feet skid height.

Adjust pedal pressure as necessary to maintain the

desired heading. Maximum torque available should be

applied (without exceeding helicopter limits) prior to

accelerating through effective transitional lift. Additional

During take-off and at any time the

forward cyclic pressure will be necessary to allow for

helicopter skids are close to the ground,

level acceleration to the desired climb airspeed.

negative pitch attitudes (nose low) of 10’

Approximately five knots prior to reaching the desired

or more can result in ground contact of

climb airspeed gradually release forward cyclic pressure

the WSPS lower cutter the forward cg.

and allow the helicopter to begin a constant airspeed

high gross weight,

high

density

climb to clear the obstacle. Care must be taken not to

altitude, transitional lift setting, and a tail

decrease airspeed during the climb out since this may

wind increases the probability of ground

result m the helicopter descending. After the obstacle is

contact.

cleared adjust helicopter attitude and collective pitch as

required to establish a climb at the desired rate and

8-32.

Deleted.

airspeed. Continuous coordinated application of control

pressures is necessary to maintain trim heading flight

8-33.

Maximum Performance.A

take-off

that

path airspeed and rate of climb. Take-off may be made

demands maximum performance from the helicopter

from the ground by positioning the cyclic control slightly

necessary because of various combinations of hear

forward of neutral prior to increasing collective pitch.

helicopter loads limited power and restricted

c Deleted.

performance due to high density altitudes barriers that

Comparison of Techniques.

Refer to

must be clean and other terrain features. The decision

Chapter 7, Performance Data for a comparison of take-

to use either of the following take-off techniques must be

off distances. Where the two techniques yield the same

based on evaluation of the conditions and helicopter

distance over a fifty-foot obstacle the coordinated climb

performance The copilot (when available) can assist the

technique will give a shorter distance over lower

pilot maintaining proper rpm by calling out rpm and

obstacles and the level acceleration technique will give a

torque power changes are made thereby allowing the

shorter distance over obstacles higher than fifty feet.

pilot more attention outside the cockpit.

The two techniques give approximately the same

distance over a fifty-foot obstacle when the helicopter

Coordinated Climb. Align the helicopter

can barely hover OGE. As hover capability is decreased

with the desired take-off course at a stabilized hover

the level acceleration technique gives increasingly

approximately three feet (skid height). Apply forward

shorter distances than the coordinated climb technique.

cyclic pressure smoothly and gradually which

In addition to the distance comparison the main

simultaneously increasing collective pitch to begin

advantages of the level acceleration technique are: (1) It

coordinated acceleration and climb.

Adjust pedal

requires less or no time in the avoid area of the height

pressure as necessary to maintain the desired heading.

velocity diagram;

(2) performance is more repeatable

Maximum torque available should be applied (without

since reference to attitude which changes with loading

exceeding helicopter limits) as the helicopter attitude is

and airspeed is not required; (3) at the higher climb out

establish that will permit safe obstacle clearance. The

airspeeds

(30 knots or greater) reliable indicate

climb out continued at that attitude and power setting

airspeeds are available for accurate airspeed reference

until t obstacle is cleared. After the obstacle is cleared

from the beginning of the climb out therefore minimizing

adjust

the possibility of descent. The main advantage of the

Change 17

8-7

TM 55-1520-210-10

coordinated climb technique is that the climb angle is

c. Landing from a Hover.

Refer to FM

1-203

established early in the take-off and more distance and time

Fundamentals of Flight 840. Engine Shutdown.

are available to abort the take-off if the obstacle cannot be

cleared Additionally large attitude changes are not required to

establish climb airspeed.

8-34.

Slingload. The slingload take-off requiring the

If throttle is inadvertently rolled to the

maximum performance (when OGB hover is not possible) is

OFF position do not attempt to roll it back

similar to the level acceleration technique except the take-off is

begun and the acceleration made above 15 feet. Obstacle

on.

heights include the additional height necessary for a 15-foot

1. Throttle Engine idle for two minutes.

sling load.

2. FORCE TRIM switch ON.

8-35. Climb. After take-off select the speed necessary to

clear obstacles. When obstacles are cleared adjust the

airspeed as desired at or above the maximum rate of climb

NOTE

airspeed. Refer to Chapter 7 for recommended airspeeds.

Steps 3 through 8 are to be completed after

8-36. Cruise. When the desired cruise altitude is reached

the last flight of the day if the system

adjust power as necessary to maintain the required airspeed.

operation was not verified during the

Refer to Chapter 7 for recommended airspeeds power settings

mission.

and fuel flow.

3. PITOT HTR Check. Place the PTOT HTR

switch in the ON position. Note loadmeter increase then OFF.

8-37. Descent. Adjust power and attitude as necessary to

attain and maintain the desired speed and rate during descent.

Refer to Chapter

7 for power requirements at selected

4. INVTR switch

OFF. Check for INST

INVERTER caution light illumination. Switch to SPARE check

airspeeds and rates of descent All checks of mission

caution light OFF.

equipment that must be made in preparation for landing

should be accomplished during descent.

5. AC voltmeter Check 112 to 118 volts.

8-38. Before landing. Prior to landing the following checks

6. MAIN GEN switch

OFF.

The DC

shall be accomplished:

GENERATOR caution light should illuminate and the standby

generator loadmeter should indicate a load

1. RPM 6600.

7. Deleted

2. Crew passengers and mission equipment--

Check.

8-39. Landing.

a. Approach Refer to the Height Velocity Diagram.

Figure 9-3 for avoid area during the approach.

b. Run-on Landing. A run-on landing may be used

during emergency conditions of hydraulic power failure and

some flight control malfunctions, and environmental

conditions. The approach is shallow and flown at-an airspeed

that provides safe helicopter control. Airspeed is maintained

as for normal approach except that touchdown is mode at an

airspeed above effective transitional lift After ground contact is

made, slowly decrease collective pitch to minimize forward

speed. If braking action is necessary, the collective pitch may

be lowered as required for quicker stopping.

Change 17 8-8

TM 55-1520-210-10

8. MAIN GEN SWITCH ON and guard dosed The DC

g. BAT.

GENERATOR caution light should be out and the main

generator loadmeter should indicate a load

13. Ignition keylock switch Remove key as required.

9. STARTER GEN switch START.

8-41. Before Leaving The Helicopter.

10. Throttle - Off.

1. Walk-around-complete, checking for damage, fluid

leaks and levels.

11. Center Pedestal switches Off.

2. Mission equipment Secure.

a. FUEL.

3. Complete DA Forms 240812 and 13. An entry in DA

Form 240813 is required if any of the following conditions were

b. Avionics.

experienced:

12. Overhead switches Off.

a. Flown in a loose grass environment.

a. INVTR.

b. Operated in a salt4aden environment.

b. PITOT HTR.

c. Exposed to radioactivity.

c. LTS.

d. Operated in rain, ice, or show.

d. MISC.

e. Operated in a volcanic ash environment.

e. CABIN HEATING.

4. Secure helicopter.

INST LTG.

Section IV. INSTRUMENT FLIGHT

8-42 Instrument Flight - General. The helicopter is qualified

flight as for visual flight Navigation and communication

for operation in instrument meteorological conditions. Flight

equipment are adequate for instrument flight Refer to FM

handling qualities, stability characteristics, and range are the

1240, Instrument Flying and Navigation for Army Aviators.

same

for

instrument

Section V. FLIGHT CHARACTERISTICS

8-43. Flight Characteristics.

flapping becomes more excessive for any given maneuver at

progressively lower load factors.

8-44. Operating Characteristics. The flight characteristics of

this helicopter in general are similar to other single rotor

a. If bumping occurs during a slope landing, reposition

helicopters.

the cyclic to stop the bumping and reestablish a hover.

8-45. Mast Bumping.

b. If bumping occurs during startup or shutdown, move

cydic to minimize or eliminate bumping.

WARNING

c. As collective pitch is reduced after engine failure or

Abrupt inputs of fight controls cause

loss of tail rotor thrust cyclic must be position to maintain

excessive main rotor flapping, which may

positive "G forces during autorotation. Touchdown should be

result in mast bumpin and must be

accomplished prior to excessive rotor rpm decay.

avoided.

8-45.1. Hub Spring Contact.

Mast bumping (flapping-stop contact) is the main yoke

contacting the mast It may occur during slope landings, rotor

a. With the addition of the Hub Spring the likelihood that

startup/coastdown, or when the flight envelope is exceeded. If

mast bumping will occur is reduced. A 2 per rev. vibration will

mast bumping is encountered in flight land as soon as

be noticed when the hub spring makes contact with the plate

possible.

At moderate to high airspeeds it becomes

assembly on the hub. With the hub spring modification,

increasingly easy to approach less than +0.5G by abrupt

contact is made at rotor flapping angles greater than

forward cyclic inputs or rapid collective reduction. Variance, in

degrees and becomes more pronounced as the angle

such things as sideslip, airspeed, gross weight, density

increases. Without the Hub Spring, contact is made at 11

altitude, center of gravity and rotor speed, may increase main

degrees (contact between yolk and mast i.e., mast bumping).

rotor flapping and increase the probability of mast bumping.

Rotor flapping is a normal part of maneuvering and while

excessive flapping can occur during flight of one G or greater,

Change 17 8-9

TM 55-1520-210-10

Due to the difference In contact limitations

d. Extreme low, and most medium frequency

(4 degrees compared to 11 degrees) it is likely that this

vibrations are caused by the rotor or dynamic controls

vibration (2 per rev ) will be felt while flying within the

Various malfunctions In stationary components can

flight envelope Gusting winds, landings with slope

affect the absorption or damping of the existing

angles, greater than 4 degrees and hoisting operations

vibrations and Increase the overall level

are several situations that increase main rotor flapping

angles, thus increasing the possibility of hub spring

e. A number of vibration are present which are

contact While the hub spring will not prohibit mast

considered a normal characteristic Two per revolution is

bumping, it will aid In controlling rotor flapping angles,

the next most prominent of these, with four or six per

and provide an extra margin of safety. Installation of the

revolution the next most prominent There Is always a

hub spring does not change In any way the approved

small amount of high-frequency vibration present that

fight envelope. Should hub spnng contact occur during

may be detectable. Expedience Is necessary to learn

normal operations, no special inspections or

the normal vibration levels. Sometimes the mistake is

maintenance actions are required Anytime operating

made of concentrating on feeling one specific vibration

limitations or the flight envelope is exceeded and hub

and concluding that the level is higher than normal.

spnng contact is encountered, a mast bump inspection

will be performed

8-53.

Low G Maneuvers.

8-46.

Collective Bounce. Collective bounce

is a pilot Induced vertical oscillation of the collective

WARNING

control system when an absolute friction (either pilot

applied or control rigged) is less than seven pounds It

may be encountered in any flight condition by a rapid

Intentional flight below

+0.SG is

buildup of vertical bounce at approximately three cycles

prohibited.

per second. The seventy of the oscillation is such that

effective control of the helicopter may become difficult to

WARNING

maintain The pilot should apply and maintain adequate

collective friction In all flight conditions

Abrupt inputs of flight controls cause

8-47.

Blade Stall. Refer to FM

1-203, Fundamentals

excessive main rotor flapping, which

of Flight

may result in mast bumping and must

8-48.

Setting with Power. Refer to FM 1-203,

be avoided.

Fundamentals of Flight

8-49.

Maneuvering Flight. Acton and response of

a. Because of mission requirements, it may be

the controls during maneuvering flight are normal at all

necessary to rapidly lower the nose of the helicopter. At

times when the helicopter is operated within the

moderate to high airspeeds, It becomes increasingly

limitations set forth In this manual

easier to approach zero or negative load factors by

8-50.

Hovering Capabilities. Refer to Chapter 7

abrupt forward cyclic inputs. The helicopter may exhibit

8-51.

Flight With External Loads. The airspeed with

a tendency to roll to the right-simultaneously with the

external cargo is limited by controllability

forward cyclic Input.

8-52.

Types of vibration.

a. The source of vibration of various frequencies

b. Such things as sideslip, weight and location of

are the rotating and moving components on the

external stores and airspeed will affect the seventy of the

helicopter, other components vibrate in response to an

right roll. Variances In gross weight longitudinal cg, and

existing vibration.

rotor rpm may affect the roll characteristics The right roll

b. Rotor vibrations felt during in-flight or ground

occurs throughout the normal operating airspeed range

operations are divided In general frequencies as follows.

and becomes more violent at progressively lower load

(1) Extreme low frequency - Less than one per

factors. When it is necessary in rapidly lower the nose of

revolution (pylon rock).

the helicopter, it is essential that the pilot monitor

(2) Low frequency - One or two per revolution

changes In roll attitude as the cyclic is moved forward.

(3) Medium frequency - Generally, four, five, or

six per revolution

c. If the flight envelope is inadvertently exceeded,

(4) High frequency - Tall rotor frequency or

causing a low "G" condition and right roll, move cyclic aft

higher

to return rotor to positive thrust condition, then roll level,

c. Most vibrations are always present at low

continuing flight if mast bumping has not occurred.

magnitudes The main problem is deciding when a

vibration level has reached the point of being excessive.

S-54. Rollover Characteristics. Refer to FM 1-203,

Fundamentals of Flight

810 Change 17

TM 55-1520-210-10

8-54.1

Operation

Differences

With

Guidance for Autorotational Flight.

Composite Main Rotor Blade.

aircraft equipped with CMRB, additional collective pitch

application may be required to maintain rpm dunng

autorotatonal maneuvering flight Collective must be

WARNING

increased simultaneously or slightly before increasing the

bank angle and/or pitch rate Rotor speed will tend to

Abrupt rolling maneuvers coupled

overspeed more rapidly and with less warning than Is

with aft cyclic inputs which induce a

charactenstc of metal main rotor blades. Additionally,

high pitch rate must not be continued

more collective application is required to control and/or

beyond the point of significantly

stop the rotor speed increase

increased one per/rev vibration

c. Guidance for Cyclic Flares Current advanced

onset.

If notably increased one

airfoils, as used on the CMRB, can cause a more raid

per/rev

vibrations occur during

rotor rpm build up dunng cyclic flare A larger collective

maneuvering flight, the severity of

input is necessary to maintain rpm within limits for this

the maneuver must be reduced or

rotor than for the metal blade rotor

control feedback and loss of aircraft

control may result.

Run-up and Shutdown Characteristics On

some UH- 1H helicopters with CMRBs, on rotor run-up

Guidance

for

Maneuvering

Flight.

and/or shutdown an audible, nonmetallic thump is heard

Increasing bank angle up to the limit will Induce

This Is normal and not a cause for any maintenance

correspondingly increasing vibration levels of the one

action or inspection. The noise is coming from the main

and two per/rev type due to hub spnng contacts. As the

bolt hole area and is caused by the combination of

bank angle limit of the aircraft is approached, the two

tolerance and torque on the joint The CMRB has an ant-

per/rev vibration increase will be the first and most

fretting pad protecting the main bolt hole area The ant-

notable vibration As the bank angle Is further increased,

fretting pad acts like a lubricant (like Teflon) and allows

a sudden increase In the one per/rev vibration will occur

the joint to relieve itself as the centrifugal force is

The one per/rev vibration will have a pounding

reduced with rpm, thus the noise The metal blade does

characteristic A slight increase in bank angle beyond this

the same thing except It does not have the ant-fretting

point could result In control feed back and exceeding the

pad Therefore, the high function In the joint allows the

flight envelope Aircraft damage and loss of aircraft

joint to relieve Itself very slowly, and no audible noise is

control may result if bank angle is further Increased The

heard This noise has also been heard when the UH-1H

aircraft bank angle limit can be reached, at the lighter

is on ground handling wheels (rotors not turning) and the

gross weights before encountering the one per/rev

helicopter Is subject to an Impact loading when the

vertical vibration, however, as gross weight Is increased,

aircraft is be towed over a sharp bump or hanger sill This

the above condition (one per/rev pounding and

noise Is also normal

feedback) will occur at reduced bank angles.

Change 17 8-10.1/(810.2 blank)

TM 55-1520-210-10

Section VI. ADVERSE ENVIRONMENTAL CONDITIONS

8-55.

General. This section provides information

main transmission driveshaft may congeal to a point that

relative to operation under adverse environmental

the couplings cannot operate properly.

conditions (snow Ice and rain turbulent air extreme cold

Transmission. Check for proper operation

and hot weather desert operations mountainous and

by turning the main rotor opposite to the direction of

altitude operation) at maximum gross weight. Section H

rotation while observer watches the driveshaft to see

check list provides for operational requirements of this

there is no tendency for the transmission to wobble

section.

while the driveshaft is turning. If found frozen apply heat

(do not use open flame, avoid overheating boot) to thaw

the spherical couplings before attempting to start engine.

Extreme care should be exercised

under

adverse

environmental

conditions when using NVG.Such

conditions deflect light and could

Prior to starting engine, on aircraft

significantly decrease or destroy

with Improved particle separators

the effectiveness of NVG to the

and parked without covers installed,

extent of creating unsafe flight

the upper half of separator should be

conditions. Use of NVG should be

removed

and

inspected

discontinued under such conditions

maintenance personnel for ice and/or

and assure that the NVG searchlight

snow. Any accumulation of these

and/or landing light and NVG position

elements should be removed to

lights may be extinguished.

prevent damage to engine.

8-56.

Cold Weather Operations. Operation of the

helicopter in cold weather or an arctic environment

c. Check.

presents no unusual problems if the operators are aware

of those changes that do take place and conditions that

(1) Before exterior check O’C (32’F) and lower.

may exist because of the lower temperatures and

Perform check as specified m Section III.

freezing moisture.

Inspection.The pilot must be more thorough

(2) Exterior check O’C (32’F) to -54’C (-65’F).

in the preflight check when temperatures have been at or

Perform the following checks. Check that all surfaces

below O’C (32’F). Water and snow may have entered

and controls are free of Ice and snow Contraction of the

many parts during operations or in periods when the

fluids in the helicopter system at extreme low

helicopter was parked unsheltered. This moisture often

temperatures causes indication of low levels. A check

remains to form ice which will immobilize moving parts or

made Just after the previous shutdown and carried

damage structure by expansion and will occasionally foul

forward to the walk around check is satisfactory If no

electric circuitry.

Protective covers afford protection

leaks are m evidence. Filling when the system is cold-

against ram, freezing ram., sleet, and snow when

soaked will reveal an over-full condition immediately after

installed on a dry helicopter pnor to the precipitation.

flight with the possibility of forced leaks at seals.

Since it is not practicable to completely cover an

unsheltered helicopter those parts not protected by

(a) Main rotor - Check free of Ice frost and

covers and those adjacent to cover overlap and joints

snow.

require closer attention especially after blowing snow

or freezing rain. Remove accumulation of snow and

(b) Main driveshaft - Check for freedom of

ice pnor to flight. Failure to do so can result m

movement.

hazardous flight due to aerodynamic and center of

gravity disturbances as well as the introduction of snow

water and ice into internal moving parts and electrical

all loose snow that could be pulled into and block the

systems. The pilot should be particularly attentive to the

engine intake during starting.

main and tail rotor systems and their exposed control

linkages.

(d) Oil cooling fan compartment - Check

oil cooling fan blades for Ice.

(3) Interior check - All flights O’C (32’F) to -

At temperatures of-35’C (-31’F) and

54’C (-65’F). Perform check as specified m Section III.

lower, the grease in the spherical

couplings of the

Change 17

8-11

TM 55-1520-210-10

(4) Engine starting check O’C (32’F) to -54’C (-

c. To minimize the effects of turbulence

65’F). As the engine cools to an ambient temperature

encountered in flight the helicopter should be flown at an

below

0’C

(32’F) after engine shutdown condensed

airspeed corresponding to

maximum endurance

moisture may freeze engine seals. Ducting hot air from

airspeed. There will be a corresponding increase in

an external source through the air inlet housing will free a

control movements at the reduced airspeed

frozen rotor. If temperature is 44’C (-47’F) or below the

pilot must be particularly careful to monitor engine and

8-62.

Thunderstorms.

transmission instruments for high oil pressure. During

cold weather starting the engine oil pressure gage will

a. To minimize the effects of thunderstorms

indicate maximum (100 psi). The engine should be

encountered in flight perform the following:

warmed up at engine idle until the engine oil pressure

indication is below 100 psi. The time required for

(1) Adjust torque to maintain maximum

warmup is entirely dependent on the starting temperature

endurance airspeed.

of the engine and lubrication system.

(2) Check that all occupants are seated with

seat belts and harnesses tightened.

(5) Engine runup check - Perform the check as

(3) PITOT HTR switch - ON.

outlined in section III.

(4) Avionics

Reduce volume on any

equipment affected by static

(5) Interior lights - Adjust to full bright at night to

WARNING

minimize blinding effect of lightning.

Control system checks should be

b. In the Storm.

performed with extreme caution when

helicopter is parked on snow and ice.

(1) Maintain a level attitude and constant power

There is reduction in ground friction

setting. Airspeed fluctuations should be expected and

holding the helicopter * stationary.

disregarded

Controls are sensitive and response

(2) Maintain original heading turning only when

is immediate.

necessary.

(3) The altimeter is unreliable due to differential

barometric pressures within the storm. An indicated gain

Engine Starting Without External Power

Supply. If a battery start must be attempted when the

or loss of several hundred feet is not uncommon-and

should be allowed for in determining minimum safe

helicopter and battery have been cold-soaked, preheat

the engine and battery if equipment is available and time

altitude.

permits. Preheating will result in a faster starter cranking

speed which tends to reduce the hot start hazard by

8-63.

Lightning Strikes.

assisting the engine to reach a self-sustaining speed (40

percent NI) m the least possible time. Electrical load

Although the possibility of a lighting strike is

may be reduced by leaving inverter lights and other

remote, with increasing use of all-weather capabilities the

helicopter could inadvertently be exposed to lightning

electrical equipment off during start.

damage. Therefore static tests have been conducted to

determine lightning strike effects on rotors

8-57.

Before Leaving the Helicopter. Open vents to

permit free circulation of air install protective covers as

Simulated lightning tests indicate that

required.

lighting strikes may damage helicopter rotors. The

degree of damage will depend on the magnitude of the

8-58.

Snow. Refer to FM 1-202 Environmental Flight.

charge and the point of contact. Catastrophic structural

failure is not anticipated. However, lightning damage to

8-59.

Desert and Hot Weather Operations. Refer to

hub bearing, blade aft section, trim tabs, and blade

FM 1-202 Environmental Flight.

tips

was demonstrated.

Also, adhesive bond

separations occurred between the blade spar and aft

8-60.

Turbulence and Thunderstorms.

section between the spar and leading edge abrasion

strip. Some portions of blade aft sections deformed to

8-61.

Turbulence.

the extent that partial or complete separation of the

a. In turbulence check that all occupants are

damaged section could be expected. Such damage can

seated with seat belts and harnesses tightened.

aerodynamically produce severe structural vibration and

b. Helicopter controllability

the primary

serious control problems which, If prolonged, could

consideration; therefore if control becomes marginal exit

endanger the helicopter and crew.

the turbulence as soon as possible.

8-12 Change 17

TM 55-1520-210-10

WARNING

When operating at outside air

temperatures of 40’F (5’C) or below

Avoid flight in or near thunderstorms

icing of the engine air inlet screens

especially in areas of observed or

can be expected. Ice accumulation

anticipated lightning discharges.

on inlet screens can be detected on

non-purging and some selfpurging

c. If lightning damage occurs, indications such as

particle

separator

systems

control problems or vibration changes, especially

illumination of the ENGINE INLET AIR

abnormal noise may or may not be evident.

cateye on the instrument panel or the

ENGINE INLET AIR caution panel

NOTE

segment

light.

Continued

Abnormal operating noises almost

accumulation of ice will result in

always accompany rotor damage, but

partial or complete power loss. It

loudness or pitch are not valid

should be noted that illumination of

indications of the degree of damage

the ENGINE INLET AIR caution light

sustained.

indicates blockage at the inlet screen

only and does not reveal icing

d. If lightning strike occurs or is suspected, the

conditions in the particle separator or

following precautions are recommended to minimize

on the FOD screen.

further risk.

To preclude the possibility of icing on

(I)

Reduce airspeed as much as practical to

aircraft equipped with non-purging or

maintain safe flight.

selfpurging particle separators, it

is recommended that the right and

(2) Avoid abrupt control inputs.

left engine air inlet filters be removed

from the cowling when it is

8-64.

Ice and Rain.

anticipated that the helicopter will be

In heavy rain, a properly adjusted wiper can

flown under atmospheric conditions

be expected to clear the windshield adequately

conductive to icing. (Do not remove

throughout the entire speed range. However, when poor

the top filter.)

visibility is encountered while cruising in rain, it is

recommended that the pilot fly by reference to the flight

NOTE

instruments and the copilot attempt to maintain visual

reference. Rain has no noticeable effect on handling or

The use of engine de-ice on aircraft

performance of the helicopter. Maintenance personnel

modified with the improved particle

are required to perform a special inspection after the

separator swirl tubes) should be limited

helicopter has been operated in ram.

to environmental conditions in which

OAT is 4’C or below.

NOTE

If icing conditions become unavoidable the

If the windshield wiper does not start in

pilot should actuate the pitot heat, windshield defroster

LOW or MED position, turn the control

and de-ice switches.

to HIGH. After the wiper starts, the

d. Flight tests in closely controlled icing conditions

control may be set at the desired

have indicated that the pilot can expect one or all of the

position.

following to occur.

(1) Obscured forward field of view due to ice

Continuous flight in light icing conditions is

accumulation on the windscreens and chin bubbles. If

not recommended because the ice shedding induces

the windshield defrosters fail to keep the windshield clear

rotor blade vibrations, adding greatly to the pilots work

of ice, the side windows may be used for visual

load If icing conditions are encountered during flight

reference during landing.

every effort should be made to vacate the icing

(2) One-per-rotor-revolution vibrations ranging

environment On aircraft modified with the improved

from mild to severe caused by asymmetrical ice

particle separator, the upper step screen may be

shedding from the main rotor system. The seventy of the

removed prior to flight if icing conditions are probable.

vibration will depend upon the temperatures and the

amount of ice

Change 17 8-13

TM 55-1520-210-10

accumulation on the blades when the ice shed occurs.

required above the cruise torque setting used prior to

Flight test experience has shown that the possibility of an

entering icing conditions it may not be possible to (

asymmetric ice shed occurring increases as the outside

maintain autorotational rotor speed within operational

air temperature decreases.

limits, should an engine failure occur.

(3) An increase m torque required to maintain a

H. Ice shed from the rotor blades and/or other

constant airspeed and altitude due to ice accumulation

rotating components presents a hazard to personnel

on the rotor system.

during landing and shutdown. Ground personnel should

remain well clear of the helicopter during landing and

(4) Possible degradation of the ability to

shutdown, and passengers and crewmembers should

maintain auto-rotational rotor speed within operating

not exit the helicopter until the rotor has stopped turning.

limits.

8-65.

High or Gusty Wind.

e. Severe vibrations may occur as a result of main

rotor asymmetrical ice shedding. If icing conditions are

a. High or gusty wind operations require no special

encountered while in flight, land as soon as practical_ All

procedures or techniques while m flight however, special

ice should be removed from the rotor system before

parking precautions are necessary to ensure that the

attempting further flight.

main rotor blades do not flex downward contacting the

tail rotor driveshaft during rotor coast down.

f. Control activity cannot be depended upon to

remove ice from the main rotor system. Vigorous control

b. To reduce the possibility of main rotor/tailboom

move-ments should not be made in an attempt to reduce

contact during engine shutdown, land the helicopter on

low frequency vibrations caused by asymmetrical

an upwind heading. During engine shutdown, displace

shedding of ice from the main rotor blades. These

cyclic into the wind, adding cyclic as necessary as rotor

movements may induce a more asymmetrical shedding

rpm decreases.

of Ice, further aggravating helicopter vibration levels.

If a

5 psi (or greater) torque pressure

increases is

8-14

Change 17

55-1520-210-10

Chapter

Emergency Procedures

Section l. HELICOPTER SYSTEMS

9-1. Helicopter Systems. This section describes the

4. AIRSPEED ADJUST as required.

helicopter systems emergencies that may reasonably be

expected to occur and presents the procedures to be

d. The term EMER SHUTDOWN is defined as engine

followed. Emergency operation of mission equipment is

stoppage without delay.

contained in this chapter insofar as its use affects safety of

flight. Emergency procedures are given in checklist form

1. THROTTLE - OFF.

when applicable. A condensed version of these procedures

is contained in the condensed checklist TM 55-1520-210

2. FUEL switches - OFF.

CL.

3. BAT switch - OFF.

9-2. Immediate Action Emergency Steps. Those

steps that must be performed immediately in an emergency

CAUTION

situation are underlined. These steps must be performed

without reference to the checklist. When the situation

The maximum engine torque available for

permits, non-underlined steps will be accomplished with

any ambient condition will be reduced by

use of the checklist.

6 to

8 PSI when the GOV AUTO/EMER

switch is placed in the EMER position.

NOTE

e. The term EMER GOV OPNS is defined as manual

The urgency of certain emergencies

control of the engine RPM with the GOV AUTO/EMER

requires immediate and instinctive action

switch in the EMER position. Because automatic

by the pilot. The most important single

acceleration, deceleration, and overspeed control are not

consideration is aircraft control. All

provided with the GOV switch in the EMER position,

procedures

are subordinate to this

throttle and collective coordinated control movements must

requirement.

be smooth to prevent compressor stall, overspeed,

overtemperature, or engine failure.

9-3. Definition Of Emergency Terms. For the

1. GOV - switch - EMER.

purpose of standardization the following definitions shall

apply:

Throttle - adjust as necessary to control RPM.

a. The term LAND AS SOON AS POSSIBLE is defined

3. Land as soon as possible.

as executing a landing to the nearest suitable landing area

without delay. The primary consideration is to assure the

survival of occupants.

9-4. Emergency Exits. Emergency exits are shown in

figure 9-1. Emergency exit release handles are yellow and

b. The term LAND AS SOON AS PRACTICABLE is

black striped.

defined as executing a landing to a suitable airfield,

a. Cockpit Doors.

heliport, or other landing area as the situation dictates.

(1) Pull handle.

c. The term AUTOROTATE is defined as adjusting the

flight controls as necessary to establish an autorotational

descent. See figure 9-2 and FM 1-203.

(2) Push door out.

1. COLLECTIVE ADJUST as required to maintain

b. Cabin Door Windows.

rotor RPM.

(1) Pull handle.

PEDALS ADJUST as required.

(2) Lift window inward.

3. THROTTLE ADJUST as required.

Change 15

9-1

55-1520-210-10

9-5. Emergency Equipment.

WARNING

Do not close the throttle. Do

not

respond to the rpm audio and/or warning

Toxic fumes of the extinguishing agent

light illumination without first confirming

may cause injury, and liquid agent may

engine malfunction by one or more of the

cause frost bite or low-temperature burns.

other indications. Normal indications

signify the engine is functioning properly

Refer to figure 9-1 for fire extinguisher and first aid kit

and that there is a tachometer generator

locations.

failure or an open circuit to the warning

system, rather than an actual engine

9-6. Minimum Rate of Descent. See figure 9-2.

malfunction.

9-7. Maximum Glide Distance. See figure 9-2.

c. Partial power condition:

9-8. Engine Oil Temperature High. If the engine oil

Under partial power conditions, the engine may operate

temperature exceeds operating limits as specified in

relatively smoothly at reduced power or it may operate

Chapter 5, land as soon as possible.

erratically with intermittent surges of power. In instances

where a power loss is experienced without accompanying

9-9. Engine Malfunction-Partial or Complete

power surging, the helicopter may sometimes be flown at

Power Loss.

reduced power to a favorable landing area. Under these

conditions, the pilot should always be prepared for a

a. The indications of an engine malfunction, either a

complete power loss. In the event a partial power condition

partial or a complete power loss are left yaw, drop in

is accompanied by erratic engine operation or power

engine rpm, drop in rotor rpm, low rpm audio alarm,

surging, and flight is to be continued, the GOV switch may

illumination of the rpm warning light, change in engine

be moved to the EMER position and throttle adjusted in an

noise.

attempt to correct the surging condition. If flight is not

possible, close the throttle completely and complete an

b. Flight characteristics:

autorotational landing.

(1) Control response with an engine inoperable is

d. Complete power loss:

similar to a descent with power.

(1) Under a complete power loss condition, delay

(2) Airspeed above the minimum rate of descent

in recognition of the malfunction, improper technique or

values (figures 9-2) will result in greater rates of descent

excessive maneuvering to reach a suitable landing area

and should only be used as necessary to extend glide

reduces the probability of a safe autorotational landing.

distance.

Flight conducted within the caution area of the height-

velocity chart (fig 9-3) or (fig 9-3.1) exposes the helicopter

(3) Airspeeds below minimum rate of descent

to a high probability of damage despite the best efforts of

airspeeds will increase rate of descent and decrease glide

the pilot.

distance.

(2) From conditions of low airspeed and low

(4) Should the engine malfunction during a left

altitude, the deceleration capability is limited, and caution

bank maneuver, right cyclic input to level the aircraft must

should be used to avoid striking the ground with the tail

be made simultaneously with collective pitch adjustment. If

rotor. Initial collective reduction will vary after an engine

the collective pitch is decreased without a corresponding

malfunction dependent upon the altitude and airspeed at

right cyclic input, the helicopter will pitch down and the roll

the time of the occurrence. For example, collective pitch

rate will increase rapidly, resulting in a significant loss of

must not be decreased when an engine failure occurs at a

altitude.

hover in ground effect; whereas, during cruise flight

conditions, altitude and airspeed are sufficient for a

significant reduction in collective pitch, thereby, allowing

rotor rpm to be maintained in the safe operating range

during autorotational descent. At high gross weights, the

rotor may tend to overspeed and require collective pitch

application to maintain the rpm below the upper limit.

Collective pitch should never be applied to reduce rpm

below normal limits for extending glide distance because of

the reduction in rpm available for use during autorotational

landing.

9-2

Change 11

55-1520-210-10

NOTE

The engine will tend to overspeed as collective pitch is

decreased and will underspeed as collective pitch is

If time permits, during the autorotative

increased. If the droop compensator fails, make minimum

descent, transmit a "May Day" call, set

collective movements and execute a shallow approach to

transponder to emergency, jettison exter-

the landing area. If unable to maintain the operating rpm

nal stores, and lock shoulder harness.

within limits:

9-10. Deleted.

EMER GOV OPNS.

9-11. Engine Malfunction - Hover.

9-15. Engine Compressor Stall. Engine compressor

stall (surge) is characterized by a sharp rumble or loud

Autorotate.

sharp reports, severe engine vibration and a rapid rise in

exhaust gas temperature (EGT) depending on the severity

9-12. Engine Malfunction

- Low Altitude/Low

of the surge. Maneuvers requiring rapid or maximum power

applications should be avoided. Should this occur.

Airspeed or Cruise.

1. Collective - Reduce.

1. Autorotate.

2. DE-ICE and BLEED AIR switches - OFF.

EMER GOV OPNS.

3. Land as soon as possible.

9-13. Engine Restart

- During Flight. After an en-

gine failure in flight, resulting from a malfunction of fuel

9-16. Inlet Guide Vane Actuator Failure - Closed

control unit, an engine start may be attempted. Because the

or Open.

exact cause of engine failure cannot be determined in flight,

the decision to attempt the start will depend on the altitude

and time available, rate of descent, potential landing areas,

a. Closed. If the guide vanes fail in the closed position,

and crew assistance available. Under ideal conditions

a maximum of 20 to 25 psi of torque will be available

approximately one minute is required to regain powered

although N1 may indicate normal. Power applications above

flight from time the attempt start is begun. If the decision is

20 to 25 psi will result in deterioration of N2 and rotor rpm

made to attempt an in-night start:

while increasing N1. Placing the GOV switch in the EMER

position will not provide any increase power capability and

1. Throttle - Off.

increases the possibility of an N1 overspeed and an engine

over-temperature. Should a failure occur, accomplish an

2. STARTER GEN switch - START.

approach and landing to the ground with torque not

exceeding the maximum available. If possible, a running

3. FUEL switches - ON.

landing is recommended.

4. GOV switch - EMER.

b. Open. If the inlet guide vanes fail in the open

position during normal flight, it is likely that no indications

5. Attempt start

wiII be evidenced. In this situation, increased acceleration

times will be experienced. As power applications are made

a. Starter switch - Press.

from increasingly lower N1 settings, acceleration times will

correspondingly increase.

b. Throttle - Open slowly to 6400 to 6600 rpm as

N1 passes through

8 percent Control rate of throttle

9-17. Engine Overspeed. Engine overspeed will be

application se necessary to prevent exceeding EGT limits.

indicated by a right yaw, rapid increase in both rotor and

engine rpm, rpm warning light illuminated, and an increase

c. Starter Switch-Release as N1 passes through

in engine noise. An engine overspeed may be caused by a

40 percent After the engine is started and powered flight is

malfunctioning N2 governor or fuel control. Although the

reestablished, continue with manual control. Turn the

initial indications of high N2 rpm and rotor rpm are the

START FUEL switch OFF and return the STARTER GEN

same in each case, actions that must be taken to control

switch to STANDBY.

rpm are distinctly different. If the N2 governor malfunctions,

throttle reduction will result in a corresponding decrease in

6. Land as soon as possible.

N2 rpm. In the event of a fuel control malfunction, throttle

reduction will have no effect on N2 rpm. If an overspeed is

9-14. Droop Compensator Failure. Droop

experienced:

compensator failure will be indicated when engine rpm

fluctuates excessively during application of collective pitch.

Change 5

9-3

TM 55-1520- 210-10

ColIective-lncrease to load the rotor in

(a) Pedal input has no effect on helicopter

trim.

an attempt to maintain rpm below the maximum

(b) Nose of the helicopter turns to the right

operating limit.

(left sideslip).

Throttle-Reduce until normal operating rpm

axis.

is attained. Continue with manual throttle control. If

(d) Nose down tucking will also be

reduction of throttle does not reduce rpm as required:

present.

WARNING

Land even If manual throttle corrects

At airspeeds below 30 to 40 knots,

the overspeed since there Is a chance

the

sideslip

may

become

of an_ Impending engine failure due

uncontrollable, and the helicopter will

to the debris generated by the Initial

begin to revolve on the vertical axis

N2 failure.

(right or left depending on power,

gross weight, etc.).

FMFRGOV OPNS.

(2) Hover.

9-18.

Transmissions and Drive Systems.

Helicopter heading cannot be controlled with pedals.

b. Procedures.

9-19.

Transmission Oil-Hot or Low Pressure. If the

(1) In- Right.

transmission oil temperature XMSN OIL Hot caution light

(a) if safe landing area is not immediately

illuminates, limits on the transmission oil temperature

available and powered flight is possible, continue flight to

gage are exceeded; XMSN OIL PRESS caution light illu-

a suitable landing area at above minimum rate of

minates, or limits on the transmission oil pressure gage

descent airspeed. Degree of roll and sideslip may be

are exceeded (low or high)-

varied by varying throttle and/or collective.

(b) When landing area is reached,

Land as soon as possible.

AUTORO TATE using an airspeed above minimum rate

of descent

FMFR SHUTDOWN - After lending.

CAUTION

WARNING

The flare and the abrupt use of

collective will cause the nose to

rotate left, but do not correct with

Do not dose throttle during this

throttle.

Although application of

emergency procedure. Descent and

throttle will result In rotation to the

landing must be made with normal

right, addition of power Is a very

engine operating RPM.

strong response measure and Is too

Should transmission oil pressure drop to zero psi, a valid

sensitive for the pilot to manage

cross reference cannot be made with the oil temperature

property at this time. DO NOT ADD

indicators. The oil temperature gage and transmission

POWER ATTHIS TIME. Slight rotation

oil hot warning lights are dependent on fluid for valid

at time of impact at zero ground

indications.

speed should not cause any real

9-20.

Tall Rotor Malfunctions. Because the many

problem.

different malfunctions that can occur, it is not possible to

provide a solution for every emergency. The success in

at a ground speed above effective transitional lift utilizing

coping with the emergency depends on quick analysis of

throttle as necessary to maintain directional control.

the condition.

(d) If landing area is not suitable for a run-

on lancing a minimum ground run autorotation must be

9-21.

Complete Loss of Tall Rotor Thrust This situ-

performed, enter autorotation descent (throttle off) start

ation involves a break in the drive system, such as a se-

to decelerate at about 75 feet altitude so that forward

vered driveshaft, wherein the tail rotor stops turning or

ground speed is at a minimum when the helicopter

tail rotor controls fail with zero thrust a Indications.

reaches 10 to 20 feet, execute the touchdown with a

(1) In-Flight.

rapid collective pull just prior to touchdown in a level

altitude with minimum ground speed.

9-4 Change 17

TM 55-1520- 210-10

(2) Hover.

(b) Delete.

AUTOROTATE.

9-23.

Loss of Tail Rotor Components. The seventy

of this situation is dependent upon the amount of weight

9-22.

Fixed Pitch Settings. This is a malfunction

lost. Any loss of this nature will result m a forward center

involving a loss of control resulting in a fixed-pitch

of gravity shift, requiring aft cyclic.

setting. Whether the nose of the helicopter yaws left or

right is dependent upon the amount of pedal applied at

a. Indications:

the time of the malfunction, a varying amount of tail rotor

thrust will be delivered at all times during flight.

(1) Varying degrees of right yaw depending on

power applied and airspeed at time of failure.

a. Reduced power (low torque).

(2) Forward CG shift.

(1) Indications: The nose of the helicopter will

turn right when power is applied.

(3) Abnormal vibrations.

(2) Procedure: Reduced power situations:

b. Procedures:

(a) If helicopter control can be maintained

(1) Enter authoritative descent (power off).

in powered flight, the best solution is to maintain control

with power and accomplish a run-on landing as soon as

(2) Maintain airspeed above minimum rate of

practicable.

descent airspeed.

(b) If

helicopter control cannot be

(3) If run-on landing is possible, complete

maintained, close the throttle immediately and

autorotation with a touchdown airspeed as required for

accomplish an autorotatlonal landing.

directional control.

b. Increased power (high torque).

(4) If run-on landing is not- possible, start to

decelerate from about 75 feet altitude, so that forward

(1) Indications: The nose of the helicopter will

groundspeed is at a minimum when the helicopter

turn left when power is reduced.

reaches 10 to

20 feet; execute the termination with a

rapid collective pull just prior to touchdown in a level

(2) Procedure.

attitude

(a) Maintain control with power and

with minimum ground speed.

airspeed between 40 and 70 knots.

9-24. Loss of Tail Rotor Effectiveness. This is a

(b)

If needed, reduce rpm (not below

situation involving a loss of effective tail rotor thrust

6000) to control sideslip.

without a break in the drive system. The condition is

most likely to occur at a hover or low airspeed as a result

landing area where a run-on landing can be

of one or more of the following.

accomplished.

(d) On final, reduce rpm to

6000 and

a. Out-of-ground effect hover.

accomplish a run-on landing.

b. High pressure altitude/high temperature.

c. Adverse wind conditions.

c. Hover.

d. Engine/rotor rpm below 6600/324.

c. Improperly rigged tail rotor.

(1) Indication. Helicopter heading cannot be

f. High gross weight.

controlled with pedals.

(1) Indications:

The first indication of this

(2) Procedure.

condition will be a slow starting right turn of the nose of

the helicopter which cannot be stopped with full left pedal

(a) Fixed Pedal-Land.

application. This turn rate will gradually increase until It

becomes uncontrollable or, depending upon conditions,

the aircraft aligns itself with the wind.

Change 17 9-5

TM 55-1520-210-10

(2) Procedures: Lower collective to regain

can be taken by the pilot is to land the helicopter.

control and as recovery is effected adjust controls for

Consideration must be given to jettison external stores

normal flight.

pnor to landing.

9-25.

Main Driveshaft Failure. A failure of the main

9-30.

Fire-Engine Start. The following procedure is

driveshaft will be indicated by a left yaw (this is caused

applicable during engine start, if EGT limits are

by the drop in torque applied to the main rotor), increase

exceeded, or if it becomes apparent that they will be

in engine rpm, decrease m rotor rpm, low rpm audio

exceeded. Flames emitting from the tailpipe are

alarm (unmodified system), and illumination of the rpm

acceptable if the EGT limits are not exceeded.

warning light. This condition will result m complete loss

of power to the rotor and a possible engine overspeed. If

Start switch - Press. The starter switch

a failure occurs:

must be held until EGT is in the normal operating range.

Autorotate.

Throttle - Off. The throttle must be closed

immediately as the starter switch is pressed.

EMER SHUTDOWN.

FUEL switches - OFF.

9-26.

Clutch Fails to Disengage. A clutch failing to

disengage in flight will be indicated by the rotor rpm

9-31.

Fire-Ground.

decaying with engine rpm as the throttle is reduced to the

engine idle position when entering autorotatlonal

EMER SHUTDOWN

descent. This condition

results in total loss of

autorotational capability. If a failure occurs, do the

9-32.

Fire-Flight. If the fire light illuminates and/or fire

following:

is observed during flight, prevailing circumstances (such

as VFR, IMC, night, altitude, and landing areas

Throttle - On.

available), must be considered in order to determine

whether to execute a power-on, or a power-off landing.

Land as soon as possible.

a. Power-On.

9-27. Clutch Fails to Re-engage. During recovery

from autorotational descent clutch malfunction may

Land as soon as possible.

occur and will be indicated by a reverse needle split

(engine rpm higher than rotor rpm):

EMER SHUTDOWN after landing.

Autorotate.

b. Power-Off.

EMER SHUTDOWN.

Autorotate.

9-28.

Collective Bounce. If collective bounce occurs.

EMER SHUTDOWN.

Relax pressure on collective. (Do not ’stiff

arm’ the collective.)

9-33.

Electrical Fire-Flight. Prior to shutting off all

Male a significant collective application

electrical power, the pilot must consider the equipment

either up or down.

that is essential to a particular flight environment that will

Increase collective friction.

be encountered, e.g., flight instruments, and fuel boost

pumps. In the event of electrical fire or suspected

9-29.

Fire. The safety of helicopter occupants is the

electrical fire in flight:

primary consideration when a fire occurs; therefore, it is

imperative that every effort be made by the flight crew to

BAT, STBY. and MAIN GEN switches -

put the fire out. On the ground it is essential that the

OFF

engine be shut down, crew and passengers evacuated

and fire fighting begun immediately. If time permits, a

Land as soon as possible.

’May Day’ radio call should be made before the electrical

power is OFF to expedite assistance from fire fighting

If landing cannot be made soon as possible and flight

equipment and personnel. If the helicopter s airborne

must be continued, the defective circuits may be

when a fire occurs, the most important single action that

identified and isolated as follows:

9-6

Change 17

TM 55-1520-210-10

Circuit breakers - Out. As each of the

the earth flying, approach and

following steps is accomplished, check for indications of

landing or while the aircraft is not in

the source of the fire.

level flight.

This prevents any

possibility of a surge in hydraulic

MAIN GEN switch - ON.

pressure and the resulting loss of

control.

STARTER GEN switch - STBY GEN.

P37. Hydraulic Power Failure. Hydraulic power failure

BAT switch - ON.

will be evident when the force required for control

movement increases; a moderate feedback m the

Circuit breakers - In. One at a time in the

controls when moved is felt, and/or the HYD PRESSURE

priority required, GEN BUS RESET first.

When

caution light illuminates. Control movements will result

malfunctioning circuit is identified, pull the applicable

m normal helicopter response. In the event of hydraulic

circuit breaker out.

power failure:

9-34.

Overheated Battery.

Airspeed - Adjust as necessary to attain

the most comfortable level of control movements.

WARNING

HYD CONT circuit breaker

Out. If

hydraulic power is not restored:

HYD CONT circuit breaker - In.

Do not open battery compartment or

HYD CONT switch - OFF.

attempt to disconnect or remove

Land as soon as practicable at an area that

overheated battery. Battery * fluid

will permit a run-on landing with power. Maintain

will cause burns and overheated

airspeed at or above effective transitional lift until

battery may cause thermal burns and

touchdown.

may explode. If an overheated battery

is suspected or detected.

9-38.

Control Stiffness.

A failure within the

irreversible valve may cause extreme stiffness in the

BAT switch - OFF.

collective or two of the four cyclic control quadrants. If

the failure is in one of the two cyclic irreversible valves,

Land ac soon as possible.

caution is necessary to avoid over controlling between

the failed and operational quadrants.

EMFR SHUTDOWN after landing.

HYD CONT switch - OFF then ON.

9-35.

Smoke and Fume Elimination. Smoke and/or

toxic fumes entering the cockpit and cabin can be

Check for restoration of normal flight control

exhausted as follows:

movements.

Repeat as necessary.

Doors. windows. and vents - Open

If control response is not restored:

HYD CONT switch - OFF.

If normal operation is not restore!

Do not jettison doors in flight

Land as soon as practicable at an area that

will permit a run-on landing with power. Maintain

9-36.

Hydraulic.

airspeed at or above effective transitional lift until

touchdown.

WARNING

9-39.

Flight Control Servo Hardover.

During actual or simulated hydraulic

a. Cyclic hardover is caused by a sequencing valve

failure, do not pull or push circuit

failure within the Irreversible valve on either or both cyclic

breakers or move the HYD CONT

servos. Cyclic servo hardover will cause the cyclic to

switch during takeoff, map of

move full night forward, full left rear, full left forward, or

full right rear.

Change 17

9-7

TM 55-1520-210-10

b. Collective hardover is caused by a sequencing

9-42.

Fuel System.

valve failure within the Irreversible valve on the collective

servo. The collective will move to the full up or full down

9-43.

Fuel Boost Pump Failure.

position.

If both FUEL BOOST caution lights come on:

c. A failure of any flight control servo may render

the helicopter uncontrollable unless the following action

Check fuel pressure.

is taken.

If fuel pressure is zero:

HYD CONT select - Select opposite

position.

Descend to a pressure altitude of 4600 feet

or less if possible.

LAND AS SOON AS POSSIBLE at an area

that will permit a run-on landing with power. Maintain

Land as soon as practicable. No attempt

airspeed at or above effective translational lift at

should be made to troubleshoot the system while in

touchdown.

flight.

9-40.

Flight Control/Main Rotor System

9-44.

Electrical System

Malfunctions.

9-45.

Main Generator Malfunction. A malfunction of

a. Failure of components within the flight control

the main generator will be indicated by zero indication of

system may be indicated through varying degrees of

the Main Generator Loadmeter and DC GENERATOR

feedback, binding, resistance, or sloppiness. These

caution light illumination. An attempt may be made to

malfunctions are normally in isolated controls, i.e. cyclic,

put the generator back on line as follows:

cyclic/collective, or anti-torque. These conditions should

not be mistaken for hydraulic power failure.

GEN and BUS RESET circuit breaker - In.

b. Imminent failure of main rotor components may

MAIN GEN switch - RESET then ON. Do

be indicated by a sudden increase in main rotor vibration

not hold the switch in the RESET POSITION. If the main

and/or unusual noise.

Severe changes in lilt

generator is not restored or If it goes off again:

characteristics and/or balance condition can occur due to

blade strikes, s kin separation, shift or loss of balance

MAIN GEN switch - OFF.

weights or other material. Malfunctions may result in

severe main rotor flapping. In the event of a main rotor

NOTE

system malfunction, proceed as follows:

Check that the standby generator

loadmeter is indicating a load Flight may

WARNING

be continued using the standby

generator.

Danger exists that the main rotor

system could collapse or separate

9-46.

Landing and Ditching.

from the aircraft after landing. A

decision must be made whether

9-47.

Landing In Trees. A landing in trees should be

occupant egress occurs before or

made when no other landing area is available. Select a

after the rotor has stopped.

landing area containing the least number of trees of

minimum height Decelerate to a zero ground speed at

Land as soon as possible.

tree-top level and descend into the trees vertically,

applying collective pitch as necessary for minimum rate

EMER SHUTDOWN after landing.

of descent. Prior to the main rotor blades entering the

trees, ensure throttle is OFF and apply all of the

9-41.

Mast Bumping.

remaining collective pitch.

If mast bumping occurs:

Reduce severity of maneuver.

Land as soon as possible.

9-8

Change 17

TM 55-1520-210-10

9-48.

Ditching-Power on. If it becomes necessary to

ditch the helicopter, accomplish an approach to an

approximate 3-foot hover above the water and proceed

as follows:

Cockpit doors - Jettison at a hover.

Cabin doors - Open.

Crew (except pilot) and passengers - Exit.

Hover a safe distance away from personnel.

Throttle-Off and autorotate. Apply full

collective pitch prior to the main rotor blades entering the

water. Maintain a level attitude as the helicopter sinks

and until it begins to roll, then apply cyclic in direction of

the roll.

Pilot-Exit when the main rotor is stopped.

9-49.

Ditching-Power Off. If ditching is imminent,

accomplish engine malfunction emergency procedures.

Decelerate to zero forward speed as the helicopter nears

the water.

Apply all of the collective pitch as the

helicopter enters the water. Maintain a level attitude as

the helicopter sinks and until it begins to roll, then apply

cyclic m the direction of the roll. Exit when the main rotor

is stopped.

Cockpit doors--Jettison

Cabin Doors - open.

Exit when main rotor has stopped

Change 17 9-8.1/(9-8.2 blank)-

55-1520-210-10

Table 9-1 Emergency Procedures for Caution Segments

Light

Corrective Action

MASTER CAUTION

Check the CAUTION panel for the condition. If

master caution only (no segment light), land

as soon as possible.

AUX FUEL LOW

INT AUX FUEL transfer switches-OFF,

DC GENERATOR

Check GEN AND BUS RESET circuit breaker

in MAIN GEN switch RESET then ON. Switch

to STBY GEN.

INST INVERTER

Switch to other inverter,

EXTERNAL POWER

Close door.

XMSM OIL PRESS

Land as soon as possible. (Ref to para 9-19)

XMSM OIL HOT

Land as soon as possible. (Ref to para 9-19)

ENGINE INLET AIR

Land as soon as practicable.

CHIP DETECTOR

Land as soon as possible.

LEFT FUEL BOOST

Land as soon as practicable.

RIGHT FUEL BOOST

Land as soon as practicable.

20 MINUTE FUEL

Land as soon as practicable.

IFF

Information/System Status

ENGINE OIL PRESS

Land as soon as possible.

ENGINE CHIP DET

Land as soon as possible.

GOV EMER

Information/System Status

ENGINE ICE DET

Land as soon as possible.

ENGINE FUEL PUMP

Land as soon as possible.

ENGINE ICING

Land as soon as possible.

FUEL FILTER

Land as soon as practicable.

HYD PRESSURE

Land as soon as practicable.

SPARE

Land as soon as possible.

Change

9-9

TM 55-1520-210-10

Appendix A

References

AR 50-4

TM 9-1005-224-12

TM 750-244-1-5

Safety Studies and Reviews of

Operator and Organizational

Procedures for the Destruction of

Nuclear Weapon Systems

Maintenance Manual Including

Aircraft and Associated Equipment

Repair Parts and Special Tool List:

to Prevent Enemy Use

AR 50-5

Machine Gun 7.62-MM M60, and

Nuclear Surety

Mount, Tripod, Machine Gun M122

DA Pam 738751

Functional Users Manual for the

AR 70-50

TM 9-1345-201-12

Army Maintenance Management

Designating and Naming Military

Operators and Organizational

System-Aviation (TAMMS-A)

Aircraft, Rockets, and Guided

Maintenance Manual: Mine Dis-

Missiles

persing Subsystem, Aircraft: M56

DOD FLIP

and M132

DOD Flight Information Publication

AR 95-1

(Enroute)

Army Aviation: Flight Regulations

TM 11-5810-262-OP

Loading Procedures, TSEC Equip

FM 1-202

Deleted

TM 11-5810-262-12&P

Environmental Flight

AR 95-27

TM 55-1500-342-23

FM 1-203

Operational Procedures for Aircraft

Army Aviation Maintenance

Fundamentals of Flight

Carrying Dangerous Materials

Engineering Manual-Weight and

Balance

FM 1-204

AR 385-40

Night Flight Techniques and

Accident Reporting and Records

TM 55-1500-334-25

Procedures

Conversion of Aircraft to Fire

TB 55-9150-200-24

Resistant Hydraulic Fluid

FM 1-240

Engine and Transmission Oils,

Instrument Flying and Navigation

Fuels

TM 55-1520-210-CL

for Army Aviators

and Additives for Army Aircraft

Operators and Crewmembers

Checklist--H-IH/V Helicopters

FM 10-68

TB MED 501

Aircraft Refueling-

Noise and Conservation of Hearing

TM 57-220

Technical Training of Parachutists

FM 10-1101

TM 9-1005-224-10

Petroleum Handling Equipment

Operators Manual for M60,

and Operation

7.62-MM Machine Gun (NSN

1005-00-605-7710)

Change 17 A-1/(A-2 blank)

Appendix B

55-1520-210-10

Abbreviations and Terms

BRIL

Brilliance

Direct Current

Alternating Current

BRT

DCP

ADF

Bright

Dispenser Control Panel

Automatic Direction Finder

AGL

Celsius

Direction Finding

Above Ground Level

CARR

DECR

Carrier

Decrease

Attack Imminent

CAS

DELTA A

ALT

Calibrated Airspeed

Incremental Change

Alternator

CCW

DET

ALT

Counter Clockwise

Detector

Altitude/Altimeter

ALTM

CDI

Directional Gyro

Altimeter

Course Deviation Indicator

DIS

Disable

Amplitude Modulation

Center of Gravity

DISP

AMP

Dispense

Ampere

Centerline

DSCRM

ANT

CMPS

Discriminator

Antenna

Compass

ECM

ATTD

CNVTR

Electronic Countermeasures

Attitude

Converter

EGT

AUTO

COLL

Exhaust Gas Temperature

Automatic

Collision

ELEC

AUX

COMM

Electrical

Auxiliary

Communication

EMER

AVGAS

COMPT

Emergency

Aviation Gasoline

Compartment

END

BAT

CONT

Endurance

Battery

Control

ENG

BDHI

CONT

Engine

Bearing Distance Heading Indicator

Continuous

ESS

BFO

CONV

Essential

Beat Frequency Oscillator

Converter

EXH

Exhaust

Butt Line

Clockwise

B - 1

55-1520-210-10

EXT

GEN

INOP

Extend

Generator

Inoperative

EXT

GND

INST

Exterior

Ground

Instrument

GOV

INT

Fahrenheit

Governor

Internal

GPU

INT

FAT

Ground Power Unit

Interphone

Free Air Temperature

GRWT

INV

FITG

Gross Weight

Inverter

Fitting

INVTR

Gross Weight

Inverter

Frequency Modulation

HDG

FOD

Heading

Infrared

Foreign Object Damage

IRT

FPS

High Frequency

Indicator Receiver Transmitter

Feet Per Second

HIT

ISA

FREQ

Health Indicator Test

International Standard Atmosphere

Frequency

HTR

KCAS

Heater

Knots Calibrated Airspeed

Fuselage Station

HYD

kHz

Hydraulic

Kilohertz

Foot

IAS

KIAS

FT/MIN

Indicated Airspeed

Knots Indicated Airspeed

Feet Per Minute

ICS

Interphone Control Station

Kilometer

FUS

Fuselage

IDENT

KTAS

Identification

Knots True Airspeed

FWD

Forward

IFF

Identification Friend or Foe

Knots

Increment of Equivalent Flat Plate

IGE

kva

Drag Area

In Ground Effect

Kilovolt-Ampere

Gravity

Inch

Kilowatt

INCR

Guard

Increase

Left

GAL

IND

Gallon

Indication/Indicator

Pounds

INHG

LDG

Guard

Inches of Mercury

Landing

B-2

TM 55-1520-210-10

APPENDIX C

TABULAR PERFORMANCE DATA

Use of the TABULAR CHARTS is illustrated by the following examples:

TABULAR PERFORMANCE DATA (Pages C-2 through C-4)

KNOWN:

Pressure Altitude (PA) = 1000 FEET

Free Air Temperature (FAT) = +25

WANTED:

Maximum GW for Hover OGE.

Torque Required for Hover OGE.

Torque Required for Hover IGE (2 FEET).

METHOD:

Enter PA at 1,000 Feet, and Move Right to +25 C.

The Top Number (912) is the Maximum GW to Hover OGE.

(= 9,120 POUNDS.)

The Middle Number (45) is the Torque required to Hover OGE at the Maximum GW to Hover OGE (9,120).

(= 45 PSI.)

The Bottom Number (37) is the Torque required at a 2 Foot Hover at the Maximum

GW to Hover OGE (9,120). (- 37 PSI.)

TABULAR PERFORMANCE DATA (Page C-5)

KNOWN:

Pressure Altitude (PA) = 1000 FEET

Free Air Temperature (FAT) = +25

WANTED:

Maximum Torque available (30 MINUTES).

METHOD:

Enter PA at 1,000 Feet, and Move Right to +20 C and +30 C.

Interpolate between 48.0 and 42.7 PSI, the Maximum Torque available will be between. (45.4)

Torque Values outlined in Tabular Data are Calibrated Values and should be converted to indicated before

use in the cockpit.

Change 17 C-1

TM 55-1520-210-10

Index

This Index is organized alphabeti-

cally by paragraph number topics.

AC Circuit Breaker Panel, 2-64

Before Leaving Helicopter Proce-

Complete Loss of Tail Rotor-

AC Power Indicators and Con-

dures-Machine Gun M60D, 4-4

Thrust, 9-21

trols,

2-63

Before Starting Engine, 8-21

Controls and Indicators,

2-26

AC Power Supply System, 2-61

Before Takeoff, 8-30

Control Stiffness,

9-38

Additional Crew,

8-9

Before Takeoff/Before Landing

Control Switch,

2-34

ADF Set AN/ARN-59,

3-19

Procedures-Machine Gun M60D,

Course

Deviations

Indicators

ADF Set AN/ARN-83,

3-18

4-3

1D-453 and ID-1347 1, 3-22

Air Induction System,

2-18

Before Takeoff-M52 Smoke Gen-

Crew and Passenger Briefings,

Airspeed Indicators, 2-76

erator Subsystem, 4-17

8-5

Airspeed Limitations,

5-11

Before Takeoff Procedures-M56

Crew Compartment Diagram, 2-8

Altitude Encoder/Pneumatic Al-

and M132 Mine Dispersing Sub-

Crew Duties, 8-6

timeter AAU-32/A, 3-28

system,

4-8

Cruise, 8-36

Anti-Collision Light, 2-66

Before Takeoff, 4-30

Cruise Conditions,

7-25,

Appendix A, References,

1-4

Before Takeoff-Rescue Hoist,

7.1-25

Appendix B, Abbreviations and

4-24

Cruise, Description,

7-23

Terms, 1-5

Blackout Curtains,

2-48

7.1-23

Approved Commercial Fuel, Oils,

Blade Stall, 8-47

Cruise, Use of Charts,

and Fluids, 2-88

Blood Bottle Hangars,

2-49

7-24

7.1-24

Armament Subsystem M23,

4-1

Cyclic Control System.

2-29

Armament Subsystem M56 and

Cyclic Hardover,

9-39

Cargo Center-of-Gravity Limits

M132 Mine Dispersing,

4-6

6-20

Army Aviation Safety Program,

Cargo Hook, 4-34

Danger Areas. 8-7

1-7

Cargo Loading,

6-14

Data Basis, 7-6

, 7.1-6

Attitude Indicators, 2-80

Center-of-Gravity Limitations,

5-8

Data Case, 2-47

Auxiliary Fuel System,

2-27

Center-of-Gravity Limits, 6-20

DC and AC Power Distribution,

Avionics Equipment Configura-

Checklist, 8-10

2-54

tion, 3-2

Checks, 8-11

DC Power Indicators and Con-

Chip Detectors, T9-1

trols,

2-59

Battery,

2-57

Circuit Breaker Panel,

2-60

DC Power Supply System, 2-55

Before-Exterior Checks, 8-12

Classification of Helicopter,

6-2

DD Form

365A-Basic Weight

Before Landing,

838

Climb,

8-35

Checklist, 6-5

Before Landing-M52 Smoke Gen-

Climb-Descent, Conditions,

DD Form 365 C-Basic Weight and

erator Subsystem,

4-19

7-31

7.1-31

Balance Records,

6-6

Before Landing Procedures-M56

Climb-Descent, Descriptions,

DD Form

365 F-Weight and

and M132 Mine Dispersing Sub-

7-29

7.1-29

Balance Clearance Form F, 6-7

system,

4-10

Climb-Descent, Use of Chart,

Definitions of Abbreviations,

Before Leaving the Helicopter,

7-30

7.1-33

7-10

7.1-10

8-41

Clutch Fails to Disengage, 9-26

Definitions of Emergency Terms,

Before Leaving the Helicopter,

Clutch Fails to Re-Engage, 9-27

9-3

8-57

Cockpit and Cabin Doors, 2-9

Descent, 8-37

Before Leaving the Helicopter-

Cockpit Map Lights, 2-70

Description, Introductory, 1-3

M52 Smoke Generator Subsys-

Cold-Weather Operations,

8-56

Desert and Hot-Weather Opera-

tem, 4-20

Collective Bounce,

8-46

tions,

8-59

Before Leaving Helicopter Proce-

Collective Bounce,

9-28

Designator Symbols, 1-10

dures-M56 and M132 Mine Dis-

Collective Control System,

2-30

Destruction of Army Materiel to

persing Subsystem,

4-11

Prevent Enemy Use_}1-8

Dimensions, 2-3

Change 8

Index 1

55-1520-210-10

Direction Finder Set ARN-89, 3-45

T9-1

Fuel Flow Description, 7-32

Direction Finder Set ARN-149,

Engine Oil Supply System, 2-20

7.1-35

3-45.1

Engine Overspeed, 9-17

Fuel Flow, Use of Chart

Distance Measuring Equipment

Engine Restart-During Flight, 9-13

7-33

7.1-36

(DME) AN/ARN-124,3-24.1

Engine Run-Up, 8-23

Fuel Supply System, 2-25

Ditching-Power Off, 9-49

Engine Shutdown, 8-40

Fuel Supply, 9-42

Ditching-Power On, 9-48

Engine Shutdown Procedures,

Fuel System Servicing, 2-87

Dome Lights, 2-69

4-33

Fuselage, 2-5

Doppler Navigation Set ASN-128,

Environmental Restrictions, 5-13

3-47

Exceeding Operational Limits, 5-3

Gearboxes, 2-40

Drag, Conditions, 7-28

Exterior Check, 8-13

General Arrangement, 2-2

7 . 1 - 2 8

Exterior Check (Area 1), 8-14

General Avionics, 3-1

Drag, Description, 7-26

Exterior Check (Area 2), 8-15

General Conditions, 7-8

7.1-26

Exterior Check (Area 3), 8-16

7.1-8

Drag, Use of Chart, 7-27

Exterior Check (Area 4), 8-17

General Description, 2-1

7 . 1 -

2 7

Exterior Check (Area 5), 8-18

General Introduction, 1-1

Driveshafts, 2-41

Exterior Check (Area 6), 8-19

Governor RPM Switch, 2-22

Droop Compensator, 2-23

External Cargo Rear-View Mirror,

Gyromagnetic Compass Set, 3-23

Droop Compensator Failure, 9-14

2-50

External Power Receptacle, 2-56

Heated Blanket Receptacles, 2-46

Electrical Circuit, 2-38

Heating and Defrosting System,

Electrical Fire Flight, 9-33

Fire, 9-29

2-53

Electrical System 9-44

Fire Detector Warning System,

Height Velocity, 5-14

Emergency Equipment 2-13

2-83

Helicopter Station Diagram 6-3

Emergency Equipment, 9-5

Fire-Engine start, 9-30

Helicopter Systems, 9-1

Emergency Exits, 9-4

Fire-Flight, 9-32

High- Performance Hoist, 4-27

Emergency Procedures-Elect-

Fire-Ground, 9-31

HF Radio Set AN/ARC-102, 3-17

cal-M56 and M 132 Mine Dispersing

First Aid Kits, 2-15

HF Radio Set AN/ARC-220, 3-17.1

Subsystem, 4-12

Fixed-Pitch Settings, 9-22

High or Gusty Wind, 8-65

Flight Characteristics, 8-43

Emergency Procedures-Fire-M56

Flight Control/Main Rotor System

Hoist Restrictions, 5-15

and M132 Mine Dispersing Subsys-

Malfunctions, 9-40

Hoist Systems, 4-21

tem. 4-13

Flight Control/Main Rotor System

Hover Conditions, 7-19

Emergency Procurers-Machine

Malfunctions, 9-48

Hover, Control Margin, 7-18

Gun M60D, 4-5

Flight Control System, Description,

7.1-18

Emer Gov Opns, 9-10

2-28

Hovering Capabilities, 8-50

Engine, 2-16

Flight With External Loads, 8-51

Engine, 9-8

FM Radio Set, 3-12

Engine Compartment Cooling, 2-17

FM Radio Set AN/ARC-44, 3-15

Engine Compressor Stall. 9-15

FM Radio Set AN/ARC-54, 3-14

Hover/Taxi Check, 8-28

Engine Fuel Control System. 2-19

FM Radio Set AN/ARC-1 31, 3-13

Hover, Use of Chart, 7-17

Engine Fuel Pump Malfunction.

Force Trim System, 2-32

7.1 -17

T9-1

Forms and Records, 1-9

Hovering Turns, 8-25

Engine Inlet Filter Clogged/Engine

Free-Air Temperature Indicator

Hydraulic, 9-36

Inlet Air Caution Light Illumination,

(FAT), 2-81

Hydraulic Filter, 2-36

T9-1

Fuel, 6-8

Hydraulic Power Failure, 9-37

Engine Instruments and Indicators.

Fuel Boost Pump Failure, 9-43

Hydraulic Pressure Caution Light,

2-24

Fuel Caution Light, 9-43.1

2-37

Fuel Filter Contamination, 9-46.

Engine Limitations, 5-7

T9-1

Hydraulic System, Description,

Engine Malfunction-Hover,

9-11

Fuel Flow, Conditions, 7-34

2-33

Engine Malfunction-Low Altitude/

7.1-37

Low Airspeed or Cruse, 9-12

Ice and Rain, 8-64

Engine Malfunction-Partial or Com-

Ignition Starter System, 2-21

plete Power Loss, 9-9

Immediate Action Emergency

Engine Oil-Hot or Low Pressure

Steps, 9-2

Index 2

Change 18

TM 55-1520-210-10

Index, 1-6

Medium-Frequency Vibrations, 8-52

Preflight Procedures-Rescue

Indicators and Caution Lights, 2-42

Minimum Crew Requirements, 5-4

Hoist, 4-23

In-Flight Procedures, 4-31

Minimum Rate of Descent, 9-6

Preparation of General Cargo,

In-Flight Procedures-Hoist

Mission Planning; 8-1

6-15

Operator, 4-32

Mode 4 Operation (APX-72 and

Pressure Altimeter, 2-79

In-Flight Procedures-Hoist

APX-100) 3-27

Prohibited Maneuvers, 5-12

Operator-Rescue Hoist, 4-26

Proximity Warning System

In-Flight Procedures-Pilot-Rescue

Normal, 8-32

YG-1054, 3-29

Hoist, 4-25

In-Flight Procedures-M52

Oil, 6-9

Radar Altimeter-AN/APN-209,

Smoke Generator Subsystem,

Oil Debris Detection System

3-31

4-18

(ODDS), 2-19

Radar Warning Set, 3-30

In-Flight Procedures-M56 and

Operating Characteristics, 8-44

Radio Receiving Set

M132 Mine Dispersing Subsystem,

Operating Limits and Restrictions,

ARN-123(V),3-46

4-9

8-2

RDU Auxiliary Input/Output

Inlet Guide Vane Actuator

Operating Limits and Restrictions,

Port Settings, Table 3-1

Failure-Closed or Open, 9-16

General, 5-2

Receiver Transmitter Radio

Instruments and Controls, 2-12

Operating Limits and Restrictions,

RT-1167/ARC-164(V),

3-322

Instruments Flight-General, 8-42

Purpose, 5-1

Rescue Hoist, 4-22

Instrument Lights, 2-71

Operating Procedures, 4-29

Reservoir and Sight Glass, 2-35

Instrument Markings, 5-5

Operating Procedures and

Rollover Characteristics, 8-54

Interior Check-Cabin, 8-20

Maneuvers, 8-8

Rotor Limitations, 5-6

Inverters, 2-82

Overheated Battery, 9-34

RPM High-Low Limit Warning

Overhead Console Panel Lights,

System, 2-85

Landing, 8-39

2-72

Landing and Ditching, 9-48

Safety-M56 and M132 Mine

Landing from a Hover, 8-29

Parachute Operations, 4-35

Dispersing Subsystem, 4-14

Landing Gear System, 2-7

Pedestal Lights, 2-73

Satellite Signals Navigation

Landing in Trees, 9-47

Performance,

8-4

Set AN/ASN-175, 3-24.2

Landing Light, 2-67

Performance Data General,

Searchlight, 2-68

Lightning Strikes, 8-63

7-3,

7.1-3

Servicing, 2-86

Limits, 7-4

Performance Data Purpose,

Settling with Power, 8-48

Loading and Unloading of Other

7-1,

7.1-1

Sideward and Rearward

Than General Cargo, 6-18

Performance Discrepancies,

Hovering Flight, 8-26

Loading Charts, 6-4

7-9

7.1-9

Signal Distribution Panel

Loading Procedures, 6-17

Personnel Compartment and

C-1611/A/C, 3-4

Loss of Tail Rotor Components, 9-23

Litter Provision, 6-10

Signal Distribution Panel

Loss of Tail Rotor Effectiveness, 9-24

Personnel Loading and Unloading,

C-6533/ARC, 3-5

Low G Maneuvers, 8-53

6-11

Signal Distribution Panel

Personnel Moments, 6-12

SB-329/AR, 3-3

M52 Smoke Generator Subsystem,

Personnel Seats, 2-11

Slingload, 8-34

4-15

Pilot/Copilot Seats, 2-10

Smoke and Fume Elimination,

Main and Standby

Pilot Heater, 2-45

9-35

Starter-Generator, 2-58

Portable Fire Extinguisher, 2-14

Snow, 8-58

Main Driveshaft Failure, 9-25

Position Lights, 2-65

Spare Lamp Kit, 2-75

Main Generator Malfunction, 9-45

Preflight Procedures, 4-28

Specific Conditions, 7-7

Main Rotor, 2-43

Preflight Procedures-M56 and

7.1-7

Maneuvering Flight, 8-49

M132 Mine Dispersing Subsystem,

Standby Compass, 2-82

Marker Beacon Receiver, 3-24

4-7

Starting Engine, 8-22

Mast Bumping, 9-41

Preflight Procedures-M52

Mast Bumping, 8-45

Smoke Generator Subsystem,

Tailboom, 2-6

Master Caution System, 2-84

4-16

Tail Rotor, 2-44

Maximum Glide Distance, 9-7

Preflight Procedures-Machine

Tail Rotor Control System,

Maximum Performance, 8-33

Gun M60D, 4-2

2-31

Change 18 Index 3

55-1520-210-10

Tail Rotor Malfunctions, 9-20

Transmission Oil-Hot or Low

Ventilating System, 2-52

Takeoff,

8-31

Pressure, 9-19

Vertical Velocity Indicator, 2-78

Takeoff, Conditions, 7-22

Transmission Oil Level Light,

VHF Navigation Set

7.1-22

2-74

AN/ARN-30E,

3-21

Takeoff Descriptions 7-20

Transponder Set AN/APX-72,

VHF Navigation Set

7.1-20

3-25

AN/ARN-82, 3-20

Takeoff to Hover, 8-24

Transponder Set AN/APX-100,

VHF Radio Set

Takeoff, Use of Charts.

3-28

AN/ARC-73,

3-11

7-21, m

7.1

-21

Turn-and-Slip, Indicator, 2-77

VHF Radio Set

Temperature Conversion,

Turbulence, 8-61

AN/ARC-116, 3-9

7.1-11

Turbulence and Thunderstorms,

VHF Radio Set

Tiedown . . Devices, -6-19

8-60

AN/ARC-134,

3-10

Thunderstorms, 8-82

Turbulence Limitations, 5-10

Voice Security Equipment

Torque Available, Chart

Turning Radius, 2-4

TSEC/KY-58, 3-16.1, 3-39

Differences, 7-13

Types of Vibration, 8-52

TSEC/KY-100,

3-17.2

Torque Available, Conditions,

7-15

7.1-15

UHF Radio Set AN/ARC-51BX,

Warnings, Cautions, and Notes

Torque Available, Description

3-6

1-2

7-12

7.1-12

UHF Radio Set AN/ARC-51X,

Weight/Balance and Loading,

Torque Available, Use of chart

3-7

8-3

UHF Radio Set AN/ARC-55B,

Weight/Balance and Loading,

Towing,

5-15

3-8

Data 6-13

Transmission,

2-39

Use of Charts, 7-5

Weight/Balance and Loading,

Transmission, and Drive

Use of Fuel, 2-89

General, 8-1

Systems Malfunctions’, 9-18

Use of Words Shall, Should,

Weight Limitations, 5-9

May, 1-11

Windshield Wiper, 2-51

Wire Strike Protection System

(WSPS), 2-12.1

Index 4

Change 18

PIN:

022124-018

The Metric System and Equivalents

Linear Measure

Liquid Measure

1 centiliter = 10 milliters = .34 fl. ounce

1 centimeter = 10 millimeters = .39 inch

1 deciliter = 10 centiliters = 3.38 fl. ounces

1 decimeter = 10 centimeters = 3.94 inches

1 liter = 10 deciliters = 33.81 fl. ounces

1 meter = 10 decimeters = 39.37 inches

1 dekaliter = 10 liters = 2.64 gallons

1 dekameter = 10 meters = 32.8 feet

1 hectoliter = 10 dekaliters = 26.42 gallons

1 hectometer = 10 dekameters = 328.08 feet

1 kiloliter = 10 hectoliters = 264.18 gallons

1 kilometer = 10 hectometers = 3,280.8 feet

Square Measure

Weights

1 sq. centimeter = 100 sq. millimeters = .155 sq. inch

1 centigram = 10 milligrams = .15 grain

1 sq. decimeter = 100 sq. centimeters = 15.5 sq. inches

1 decigram = 10 centigrams = 1.54 grains

1 sq. meter (centare) = 100 sq. decimeters = 10.76 sq. feet

1 gram = 10 decigram = .035 ounce

1 sq. dekameter (are) = 100 sq. meters = 1,076.4 sq. feet

1 dekagram = 10 grams = .35 ounce

1 sq. hectometer (hectare) = 100 sq. dekameters = 2.47 acres

1 hectogram = 10 dekagrams = 3.52 ounces

1 sq. kilometer = 100 sq. hectometers = .386 sq. mile

1 kilogram = 10 hectograms = 2.2 pounds

1 quintal = 100 kilograms = 220.46 pounds

Cubic Measure

1 metric ton = 10 quintals = 1.1 short tons

1 cu. centimeter = 1000 cu. millimeters = .06 cu. inch

1 cu. decimeter = 1000 cu. centimeters = 61.02 cu. inches

1 cu. meter = 1000 cu. decimeters = 35.31 cu. feet

Approximate Conversion Factors

To change

Multiply by

To cbange

inches

centimeters

2.540

ounce-inches

newton-meters

.007062

feet

meters

.305

centimeters

inches

.394

yards

meters

.914

meters

feet

3.280

miles

kilometers

1.609

meters

yards

1.094

square inches

square centimeters

6.451

kilometers

miles

.621

square feet

square meters

.093

square centimeters

square inches

.155

square yards

square meters

.836

square meters

square feet

10.764

square miles

square kilometers

2.590

square meters

square yards

1.196

acres

square hectometers

.405

square kilometers

square miles

.386

cubic feet

cubic meters

.028

square hectometers

acres

2.471

cubic yards

cubic meters

.765

cubic meters

cubic feet

35.315

fluid ounces

milliliters

29,573

cubic meters

cubic yards

1.308

pints

liters

.473

milliliters

fluid ounces

.034

quarts

liters

.946

liters

pints

2.113

gallons

liters

3.785

liters

quarts

1.057

ounces

grams

28.349

liters

gallons

.264

pounds

kilograms

.454

grams

ounces

.035

short tons

metric tons

.907

kilograms

pounds

2.205

pound-feet

newton-meters

1.356

metric tons

short tons

1.102

pound-inches

newton-meters

.11296

Temperature (Exact)

⁰F Fahrenheit

5/9 (after

Celsius

°c

temperature

subtracting 32)

temperature

ARMY MODEL UH-1H/V HELICOPTERS. OPERATOR’S MANUAL (1988) - page 5