Rolls-Royce Engine 250–C18, 250–C18A, 250–C18B, 250–C18C. Operation and Maintenance Manual (2003)

A. The effect of anti-icing air flow on engine performance is as follows:

Anti-icing Air Flow On Engine Performance

Type of Operation

Approximate Effect on Performance Available to Pilot at

Power Levels Above 40,000 N₁ Speed*

Constant TOT 1280° F (693° C) Max Con-

A 30 hp decrease and a 1000 rpm (1.95%) decrease in N₁

tinuous

(gas producer) speed

Constant N₁ speed 100% (51,120 rpm)

A 7 hp decrease and a 45° F (25° C) increase in TOT

Constant hp (270) and constant collective

A 300 rpm (0.59%) increase in N₁ speed and a 60° F (33° C)

pitch (load) operation

increase in TOT

*These values are for Standard Day Sea Level conditions and will vary with changes in ambient temperature and

altitude. The effects at lower powers and speeds will be only slightly different but still immediate and definite.

Compressor Bleed Air System

The compressor bleed air system permits rapid engine response. The system consists of a compressor

discharge pressure sensing port on the scroll, tubing from the sensing port to the bleed valve, a

compressor bleed control valve (Ref. FIG. 14, and 15 ), and a bleed air manifold on the compressor

case.

Elongated slots between every other vane at the compressor fifth stage, bleeds compressor air into a

manifold which is an integral part of the compressor case. The manifold forms the mounting flange for

the compressor bleed control valve when the compressor case halves are assembled.

Compressor discharge air pressure sensing, for bleed control valve operation, is obtained at a sensing

port on the compressor scroll. The bleed control valve is normally open; it is closed by compressor

discharge pressure. Ref. 16 for bleed control valve opening and closing speeds.

10.

Water-Alcohol System

The Model 250-C18B engine is the same as a Model 250-C18 and the Model 250-C18C is the same as

a Model 250-C18A except that water-alcohol (W/A) augmentation systems have been added. The

systems are added to provide additional takeoff power when operating in high ambient temperatures.

Ref. FIG. 17 and 18 for additional information.

A. Water-Alcohol System Components. The only engine-furnished components of the system are

two injection nozzles which are airframe mounted. Other components of the system are airframe

furnished.

(1) The water-alcohol augmented engine must be equipped with compressor discharge air tubes

PN 6856799 or 6874944. Also, the system requires a 200-mesh filter upstream of the

injection nozzles.

B. Water-Alcohol Injection Nozzles. Each nozzle is designed to flow a nominal 0.625 gpm (2.36 L pm)

at a pressure drop of 50 psi (345 kpa) on a 95°F (35°C) standard day. Flow rates are based on a

water-alcohol mixture of one part by volume methyl alcohol and two parts by volume purified water.

The water and alcohol shall conform to the following standards:

(1) Water. Purified water obtained by the distillation process or water meeting the following

requirements:

Purified Water Requirements

Chemical Requirement

Test Method*

Total solids, ppm

15.0 max

ASTM D-1069-66

Dissolved solids, ppm

10.0 max

ASTM D-1069-66

Total hardness, epm

0.2 max

ASTM D-1126-65

6.5-7.5

ASTM D-1293-65

* Refer 1966 American Society of Testing Materials Standards, Part 23.

Page 22

WARNING: THE MAXIMUM OIL CONSUMPTION LIMIT IS 0.05 U.S. GALLONS PER HOUR (1

QUART IN FIVE HOURS). OPERATION IN EXCESS OF THIS LIMIT IS NOT

PERMITTED. EXCESSIVE OIL CONSUMPTION CAN BE INDICATIVE OF A SERIOUS

INTERNAL OIL LEAK. AN INTERNAL OIL LEAK CAN RESULT IN AN UNDETECTED

INTERNAL OIL FIRE, WHICH WILL RESULT IN A DISASTROUS TURBINE FAILURE.

11. Engine Specifications/Ratings - Engine specifications, limits, and performance ratings are as follows:

Engine Specifications/Ratings

Design power output

317 shp

Design speeds:

Gas producer

100% (51,120 rpm)

Power turbine

100% (35,000 rpm)

Power output shaft

6,000 rpm

Maximum measured gas temperature stabilized (TOT)

1380° F (749° C)

Dimensions:

Length

40.4 in. (1026 mm)

Height

22.5 in. (572 mm)

Width

19.0 in. (483 mm)

Engine weight (dry)

141 lb

(63.96 kg) (250-C18, -C18A)

141.2 lb (64.05 kg) (250-C18B, -C18C)

Maximum oil consumption

0.05 U.S. gal/hr or 1 qt in 5 hours (0.9 liter in 5

hrs)

Performance ratings*

See Tables 1 and 2

* The performance ratings in Table 1 also apply to 250-C18B and 250-C18C engines.

Table 1

250-C18B and 250-C18C Performance Ratings (Standard Sea Level 95° F Ambient Static Conditions)

Ram Power

Measure

Output Shaft-

N1, Gas Pro-

Rating Torque

N2, Power

Specific Fuel Con-

Rated Gas

fower (min)

ducer Speed

at Output

Turbine Speed

Output Shaft

sumption (max)

Temperature

Rating

% rpm

rpm

lb/shp- hr mg/W⋅h

Shaft (max)

° F

° C

ft-lb

N⋅m

Takeoff

317

236

100.9

51,600

100

35,000

100

6,000

0.697

423.97

293

397

1380

749

Max Cont

270

201

97.3

49,760

100

35,000

100

6,000

0.706

429.44

249

338

1280

693

(M. C.)

Cruise A

243

181

95.2

48,650

100

35,000

100

6,000

0.725

441.00

249

338

1226

663

(90% M.C.)

Cruise B

203

151

91.8

46,950

100

35,000

100

6,000

0.762

463.50

249

338

1148

620

(75% M.C.)

Ground Idle

62.6

32,000

75-

26,250-

75-

4,500-

61 lb/hr

27.67kg/

750±100

399

105

36,750

±55

105

6,300

Flight Auto-

0 max

62.6

32,000

98.3- 34,417-

98.3-

5,900-

61 lb/hr

27.67kg/

725±100

385

rotation

106

37,100

106

6,360

±55

Page 27

Table 2

250-C18 and 250-C18C Performance Ratings (Sea Level 95° F Ambient Static Conditions)

Ram Power Rating Torq-

Measured Rated Gas

ue at Output Shaft (max)

Output Shaft

Temperature (max)

Output Shaft (min)

(rpm)

° F

°C

Rating

lb-ft

N⋅m

Takeoff*

(Augmented)

310

231

100

6,000

293

397

1380

749

* Augmented takeoffs are limited to ambient temperatures above 40° F (4° C) and shall not exceed five minutes

duration. The above rating is based on a water-alcohol flow rate of 1.25 gallons per minute (gpm) (4.73 l/min)

delivered to the injection nozzles at a pressure differential of 50 psi (345) kPa across each nozzle.

12.

Fuel Specification

WARNING: TO PREVENT ENGINE FUEL SYSTEM CONTAMINATION, WHICH COULD CAUSE

ENGINE FLAMEOUT, AN EXTERNAL LOW PRESSURE FUEL FILTER SHOULD BE

USED ON ANY AIRCRAFT REFUELING FROM REMOTE FUELING SITES (DRUMS

ETC).

CAUTION: NOT ALL NO. 1 DIESEL FUELS, JP-1, OR ARCTIC DIESEL FUELS WILL MEET THE

PRIMARY FUEL SPECIFICATIONS. IN DETERMINING WHETHER OR NOT A GIVEN

FUEL MEETS THESE SPECIFICATIONS, THE BURDEN OF PROOF RESTS WITH

THE OPERATOR AND HIS SUPPLIER.

Primary Fuel

MIL-T-5624, grade JP-4 and JP-5

MIL-T-83133, grade JP-8

ASTM D-1655, Jet B

ASTM D-1655, Jet A or A1

JP-1 fuel conforming to ASTM D-1655,

Jet A

Arctic Diesel Fuel DF-A (VV-F-800B)

conforming to ASTM D-1655, Jet A or

Jet A1

Diesel #1 fuel conforming to ASTM

D-1655, Jet A

CAUTION: MIL-G-5572 FUEL CONTAINING TRICRESYLPHOSPHATE (TCP) ADDITIVE

SHALL NOT BE USED.

Emergency Fuel

MIL-G-5572E, all grades (aircraft boost

pump on; maximum of 6 hours operation

per overhaul period of turbine)

WARNING: AT AMBIENT TEMPERATURES BELOW 40° F (4° C), SOME TYPE OF ANTI-ICE

PROTECTION IS REQUIRED, SUCH AS AN ANTI-ICE ADDITIVE OR A MEANS

OF AIRFRAME FUEL ICE ELIMINATION. ENGINE FLAMEOUT COULD RESULT

FROM FAILURE TO USE ANTI-ICE PROTECTION. (REFER TO THE AIRCRAFT

MANUAL FOR THEIR RECOMMENDATIONS.)

NOTE: JP-4, JP-5 and JP-8 type fuels conforming to MIL-T-5624 or MIL-T-83133A or

later contain an anti-ice additive which conforms to MIL-I-27686 or later and do not

require additional anti-ice additives unless specified by the airframe manufacturer.

Cold Weather

To ensure consistent starts below 4° C

(40° F) the following fuels may be neces-

sary:

MIL-T-5624, grade JP-4

Page 28

Cold Weather - continued

ASTM D-1655, Jet B

AVGAS/Jet A, Jet A1, or JP-5 mixture

(Refer to Cold Weather Fuels, Section II

para10, for mixing/use of cold weather

fuel.)

NOTE: Jet A, A1, JP-5, or JP-8 fuels are not restricted from use at ambient temperatures below 0°F

(-18°C); however, special provisions for starting must be made. (Refer to Aircraft Flight

Manual.) Once started, engine operation on Jet A, Jet A1, JP-5, or JP-8 will be satisfactory in

outside air temperatures down to -25°F (-32°C).

NOTE: Prolonged and uninterrupted operation with only AVGAS mixture will induce lead buildup on

turbine parts. This lead buildup can cause a gradual power reduction; consequently, this

AVGAS mixture should be used only for cold weather operation. During operation with normal

Jet A type fuel, the lead will slowly dissipate.

A. Prist anti-ice additive( MIL-I-27686E) is approved for use in the model 250-C18 series engines if

used in accordance with the additive manufacturer’s instructions and if approved by the airframe

manufacturer.

13.

Oil Specification

A. The 250 series engines are qualified and certified for use with only certain MIL-PRF-7808G,

subsequent MIL-PRF-23699 series, and DOD-85734 series lubricating oils. Vendor brands of

MIL-PRF-7808 series, MIL-PRF-23699 series and DOD-85734 series lubricating oils which have

been engine tested and approved for use in the Model 250 engine are listed para C. Refer to

paragraph B. for the type of oil recommended at specific temperatures.

WARNING: ONLY DISCRETIONARY MIXING OF OILS WITHIN AN OIL SERIES IS PERMITED

WITHOUT A TIME PENALTY. USE OF MIXED OILS FROM DIFFERENT SERIES IN

AN ENGINE IS LIMITED TO FIVE HOURS TOTAL RUNNING TIME DURING ONE

OVERHAUL PERIOD. ADEQUATE MAINTENANCE RECORDS MUST BE

MAINTAINED TO ENSURE THAT THE FIVE HOUR LIMIT IS NOT EXCEEDED.

FAILURE TO COMPLY WITH OIL MIXING RESTRICTIONS CAN RESULT IN ENGINE

FAILURE.

CAUTION: IF BRANDS OF OILS ARE CHANGED, IT IS RECOMMENDED THIS CHANGE BE

ACCOMPLISHED GRADUALLY USING A ‘‘TOP-OFF’’ METHOD OR BY DRAINING

AND REFILLING. IN THE TOP-OFF METHOD, OIL OF THE NEW BRAND IS ADDED

AS OIL IS CONSUMED BY THE ENGINE. IN THE EVENT OIL BRANDS ARE

CHANGED BY DRAINING AND REFILLING THE LUBRICATION SYSTEM, WATCH

FOR POSSIBLE BYPASS INDICATIONS. THESE INDICATIONS COULD BE AN

INDICATION OF CARBON OR COKE, WHICH WAS FORMED DURING PREVIOUS

OPERATION, BEING DISLODGED DURING OPERATION FOLLOWING THE CHANGE.

CAUTION: IF HEAVY CARBON OR COKE DEPOSITS ARE FOUND ON THE ENGINE FILTER

DURING REGULAR INSPECTIONS, IT IS RECOMMENDED THE FILTERS BE

REPLACED; CONTINUE TO MONITOR BYPASS INDICATORS.

CAUTION: TO DECREASE THE LIKELIHOOD FOR CARBON OR COKE DEPOSITS BEING

DISLODGED DURING THE CHANGEOVER TO ‘‘3RD GENERATION’’ OILS (E.G.

MOBIL JET 254), THESE CHANGEOVERS SHOULD ONLY BE MADE WHEN THE

ENGINE IS NEW OR REPAIRED, TO THE EXTENT THE LUBRICATION PASSAGES

AND SUMPS HAVE BEEN CLEANED AND FLUSHED

Page 29

CAUTION:

WHILE CONSIDERABLE LABORATORY DATA IS AVAILABLE TO DEMONSTRATE

THE COMPATIBILITY OF ONE SYNTHETIC TURBINE OIL WITH OTHER TURBINE

OILS MEETING THE SAME SPECIFICATION (EXPERIENCE ALSO DEMONSTRATES

THIS PROPERTY), THE INDISCRIMINATE MIXING OF APPROVED OILS DURING

THE OPERATIONAL USE OF THE OIL IS NOT RECOMMENDED. HOWEVER, THERE

MAY BE CIRCUMSTANCES WHERE EMERGENCY TOP-OFF, INADVERTENT

MIXING, OR CHANGEOVER BY ‘‘TOP-OFF’’ TO ANOTHER BRAND MAY OCCUR.

THESE ARE ACCEPTED PRACTICES.

CAUTION:

FAILURE TO COMPLY WITH OIL MIXING RESTRICTIONS CAN RESULT IN ENGINE

FAILURE.

CAUTION:

REMOVE AND INSPECT THE OIL FILTER AFTER THE FIRST 25 HOURS OF ENGINE

OPERATION IF THE TYPE OF OIL (MIL-PRF-7808, MIL-PRF-23699, OR DOD-

85734) IS CHANGED. REPEAT THE FILTER INSPECTION EACH 25 HOURS AS

REQUIRED UNTIL EXCESSIVE CARBON PARTICLE ACCUMULATION SUBSIDES.

CAUTION:

THE FILTER INSPECTION IS TO DETERMINE IF COKE, WHICH WAS FORMED

DURING PREVIOUS OPERATION, IS BEING DISLODGED DURING THE FIRST

OPERATION FOLLOWING THE OIL CHANGE.

CAUTION:

IF HEAVY CARBON DEPOSITS ARE OBSERVED ON THE ENGINE FILTER, IT IS

SUGGESTED THAT THE ENGINE OIL BE CHANGED AGAIN. THE OIL IS TO BE

DRAINED WHEN THE OIL IS HOT TO OBTAIN THE MAXIMUM BENEFIT. THE 25

HOUR OIL MONITORING IS TO CONTINUE UNTIL THE NEXT OIL CHANGE PERIOD.

CAUTION:

USE OF OILS WHICH ARE NOT INCLUDED IN THE APPROVED OILS LISTING, OR

FAILURE TO DRAIN OIL WITHIN THE PRESCRIBED INTERVAL GIVEN IN TABLE 604,

72-00-00, ENGINE-INSPECTION/CHECK WILL BE CONSIDERED AS MISUSE

UNDER ITEM (4) OF THE WARRANTY POLICY.

NOTE:

Because of availability, reduced coking, and better lubricating qualities at higher

temperatures, qualified MIL-PRF-23699 oils are preferred for use in Model 250 engines.

Check the aircraft oil quantity within 15 minutes of engine shutdown to avoid a false

indication of excessive oil consumption. If the 15 minutes has been exceeded, motor the

engine for 30 seconds with the starter before checking tank quantity. Motoring normally

scavenges oil from the gearbox back to the aircraft oil tank. Check the airframe flight

manual; some installations may require engine to be operated for at least a minute at

ground idle to assure proper scavenging of the engine gearbox.

Always refer to the airframe flight manual for proper oil servicing instructions; specific

requirements may vary for different models.

Cold Weather Lubrication

The types of oil recommended at specific ambient temperatures are as follows:

Ambient Temperature

Oil Series

0°C (32°F) and above

MIL-PRF-23699C or subsequent

preferred

0°C (32°F) to -40°C (-40°F)

MIL-PRF-23699C or subsequent

preferred or MIL-PRF-7808G or

subsequent

-40°C (-40°F) and below

MIL-PRF-7808G or subsequent only

-40°C (-40°F) to135°C (275°F)

DOD- 85734

Page 30

C. Approved Oils

Manufacturer’s Designation & Address

MIL-PRF-7808 Series

MIL-PRF-23699 Series (cont)

(Formerly MIL-L-7808)

(Formely MIL-L-23699)

American PQ Lubricant 689

Caltex RPM Jet Engine Oil 5

American Oil & Supply Co.

Caltex Petroleum Corporation

238 Wilson Avenue

380 Madison Avenue

Newark, New Jersey 07105

New York, New York 10017

Brayco 880

Castrol Aero Jet5

Castrol Inc.

Specialty Products Division

1001 West 31st Street

16715 Von Karman Ave, Suite 230

Dowers Grove, IL 60515

Irving, California 92714

EXXON Turbo Oil 2389

Cheveron Jet Engine Oil 5

EXXON Company, U.S.A.

Chevron International Oil Company

P.O. Box 2180

555 Market Street

Houston, Texas 77252-2180

San Francisco, California 94105

Mobil Avrex S Turbo 256

EXXON Turbo Oil 2380

Mobil OIl Corporation

EXXON Company, USA

3225 Gallows Road

P.O. Box 2180

Fairfax, Virginia

22037

Houston, Texas 77252-2180

Mobil RM-184A and

Hatcol 3211

Mobil RM-201A

Hatcol Corporation

Mobil Oil Corporation

King George Post Road

3225 Gallows Road

Fords, New Jersey 08863

Fairfax, Virginia

22037

Stauffer Jet 1

Mobil Jet Oil II

Stauffer Chemical Co.

Mobil Oil Corporation

380 Madison Avenue

3225 Gallows Road

New York, New York 10017

Fairfax, Virginia

22037

Stauffer Jet II (Castrol 205)

Stauffer Chemical Company

MIL-PRF-23699 Series

380 Madison Avenue

(Formerly MIL-L-23699)

New York, New York 10017

Aeroshell/Royco Turbine Oil 500

Turbonycoil 600 (TN600)

Royal Lubricants Company, Inc.

NYCO S.A.

River Road, P.O. Box 518

66, Champs-Elysees-51

East Hanover, New Jersey 07936

Rue De Ponthieu

75008 Paris

American PQ Lubricant 6700

American Oil and Supply Co.

238 Wilson Avenue

Newark, New Jersey 07105

Brayco 899

Castrol Inc.

Specialty Products Division

16715 Von Karman Ave., Suite 230

Los Angeles, California 90032

Page 31

Manufacturer’s Designation & Address

MIL-PRF-23699F Series

High Thermal Stability (HTS)

DOD-85734 Series

Aeroshell/Royco Turbine Oil 560

Aeroshell/Royco Turbine Oil 555

Royal Lubricants Company, Inc.

River Road, P.O. Box 518

River Road , P.O. Box 518

East Hanover, New Jersey 07936

Aeroshell Turbine Oil 560

NOTE: Long term use of Aeroshell/Royco

Shell International Petroleum Co., Ltd.

555 oil may increase the probability of

International Aviation Sales Division

silicone rubber seal leakage in the

Shell Centre

accessory gearbox.

London, SEI 7NA, England

EXXON ETO 2197 (BPTO 2197)

Aeroshell Tubine Oil 555

Air BP

Shell International Petroleum Co., Ltd

BP Exploration & Oil, Inc

International Aviation Sales Division

Maple Plaza II-1N

Shell Centre

Six Campus Drive

London, SEI 7NA, England

Parsippany, NJ 07054

Mobil Jet Oil 254 and

NOTE: Long term use of Aeroshell 555 oil

Mobil Jet Oil 291

may increase the probability of silicone

Mobil Oil Corporation

rubber seal leakage in the accessory

3225 Gallows Road

gearbox.

Fairfax, Virginia 22037

14.

Engine Trend Check Analysis

The trend check analysis provides a method for the operator to monitor engine health. The trend

check will also allow the operator to more effectively predict when preventative maintenance is

required and schedule some maintenance actions that were formerly unscheduled.

Rolls-Royce Engine Company encourages all operators on a voluntary basis to utilize performance

trending to supplement their regular maintenance program. It should be noted that the use of

performance trending does not change the requirement to operate the engine within established

limits and according to applicable publications. Aircraft manufacturer engine trending procedures

that are published in the applicable FAA approved flight manuals can be used in lieu of the

procedure given in this manual if they are Rolls-Royce approved. (Refer to Aircraft Manufacturer

Trend Check-Alternate Procedure, Section II.)

The analysis given in the Trend Check Procedure, Section II, Engine Inspection/Check provides

the necessary guidance, procedures, check lists, correction Table’s and graphic examples required

to set up an engine trend check program. A trend check program can be initiated at any point in an

engine’s life. The effectiveness of the trending program is dependent on the quality of the

uncorrected data. Anything that causes the inflight data to be in error will reflect adversely on the

effectiveness of the program.

Consideration should be made for tolerances on the accuracy of aircraft installed instruments.

Instrument error could affect measured performance by approximately the following:

(1)

4% below actual power available for every +5° C error in outside air temperature (OAT). Use a

precision mercury type thermometer in the immediate vicinity of the OAT probe. Shade both

thermometers for a minimum of 15 minutes before taking a reading. Compare accuracy of

installed OAT gauge.

(2)

1% below actual power available for every 300 feet error in pressure altitude. Determine

pressure altitude by averaging the readings of altimeters of known accuracy on the flight deck.

Page 32

ENGINE OPERATION

Engine Operating Precautions

WARNING: THE PRIMARY APPLICATION OF THIS TURBOSHAFT ENGINE IS TO

POWER A HELICOPTER OR ROTOCRAFT. A HEIGHT-VELOCITY DIAGRAM, AS

REQUIRED BY REGULATION AND PREPARED BY THE AIRFRAME

MANUFACTURER, IS PUBLISHED IN THE AIRCRAFT FLIGHT MANUAL

PERFORMANCE SECTION FOR NORMAL CATEGORY ROTORCRAFT. THE

OPERATOR MUST BECOME FAMILIAR WITH THIS DIAGRAM TO DETERMINE WHAT

ALTITUDES AND AIRSPEEDS ARE REQUIRED TO SAFELY MAKE AN

AUTOROTATIONAL LANDING IN CASE OF POWER LOSS OR ENGINE FAILURE.

THE ALTITUDE-AIRSPEED COMBINATIONS WHERE A SAFE AUTOROTATIONAL

LANDING MAY NOT BE POSSIBLE ARE REPRESENTED BY THE SHADED OF

CROSS-HATCHED AREA OF THE DIAGRAM.

WARNING: SNOW OR ICE SLUGS CAN CAUSE THE ENGINE TO FLAME OUT. BE SURE

AVAILABLE PREVENTIVE EQUIPMENT IS INSTALLED AND IN PROPER WORKING

ORDER WHEN FLYING IN CONDITIONS WHERE SNOW OR ICE BUILDUP MIGHT

OCCUR.

WARNING: CONSULT THE AIRCRAFT FLIGHT MANUAL FOR REQUIRED EQUIPMENT AND

PROCEDURES FOR FLIGHT IN FALLING/BLOWING SNOW.

WARNING: SAND AND DUST WILL ERODE COMPRESSOR VANES AND CAUSE THEM TO FAIL.

WARNING: SALT LADEN HUMIDITY AND CHEMICALS WILL CORRODE COMPRESSOR BLADES

AND VANES AND CAUSE THEM TO FAIL.

A. Observe the following precautions to reduce the danger of personnel injury or damage to the

engine.

(1) Before operating the engine, check the air inlet for foreign objects. (Refer to Compressor Inlet

Air Blockage, Section III.)

(2) If the engine does not operate within the limits of Operating Limits, para 2, take the designated

action.

(3) If the aircraft is frequently operated in dusty or sandy areas, periodic erosion inspection is

recommended. (Refer to Erosion Inspection, Section III.)

(4) If a flameout has been experienced as the possible result of snow, ice, or water ingestion refer

to Snow Ingestion Inspection, Section III.

(5) If the aircraft is being operated following an extended period of inactivity, refer to Special

Inspections, Section III, Table 9 for recommended action.

(6) If the engine is operated in a salt water environment it must be subjected to a water wash.

(Refer to Compressor Salt Water Contamination Removal, Section III.)

(7) If the installed engine will be shut down for more than five calendar days the compressor must

receive an application of preservative. (Refer to Compressor Preservation, Section III.)

Engine Operating Limits

WARNING: TO PREVENT SERIOUS ENGINE MALFUNCTION OR CRUCIAL LOSS OF POWER, DO

NOT OPERATE THE ENGINE IN EXCESS OF ANY SPECIFIED LIMIT.

NOTE: Operators may be faced with an engine that meets all specification power requirements in a

certified test cell; but, apparently fails to meet the minimum installed power required by the

aircraft flight manual. Please refer to the Aircraft Manual for other system troubleshooting.

NOTE: Operators should be aware that the FAA requires the Rolls-Royce Authorized Maintenance

Centers (AMC) to deliver engines of at least “specification horsepower” only after complete

engine overhaul.

Page 1

Power Turbine Speed Restrictions

The following N₂ speed restrictions are applicable to engines having the power and accessories gearbox

assemblies with the following serial numbers: CAG 20183, 20185, 20193 through 20265, 20508, 21001

through 21395, 21600 through 21706, and 21800 through 21803. The restrictions shall be lifted only

after the gearbox has been reworked in accordance with Rolls-Royce Commercial Engine Bulletin 250

CEB-90.

A. Adjust N₁ speed at ground idle so N₂ speed does not exceed 71% rpm.

B. Avoid steady state operation at any flight or ground condition, other than ground idle or practice

autorotation, at engine N₂ speeds below 98% or above 102% rpm.

Temperature

WARNING: HOT STARTS OR AFTERFIRES AFTER SHUTDOWN CAN CAUSE TURBINE BLADE

AND WHEEL DAMAGE RESULTING IN ENGINE FAILURE.

A. Refer to Table 1 for the measured gas temperature limits and the action to be taken when they are

exceeded.

TABLE 1

Measured Gas Temperature Limits (TOT)

Temperature Range

Time

Maintenance Action

Steady State

749°C (1380° F)

Takeoff (5 min.)

If steady-state time or condition

limits are exceeded, inspect tur-

bine.

(2)

749°C (1380° F)

30 Minute Power (1)

693°C (1280° F)

Max Continuous and Below

During Starting and Shutdown

Up to 749° C (1380° F)

No limit

None

749-927° C

(1380-1700° F)

Over 10 sec (3)

Inspect turbine (2)

927-999° C (1700-1830° F)

Not allowed (3)

Inspect turbine (2)

Over 999° C (18300° F)

Not allowed

Remove turbine for heavy mainte-

nance or overhaul.

NOTE: Refer to Section III, Troubleshooting (item 4) when start temperature consistently exceeds

843° C (1550° F).

During Power Transient

Up to 693° C (1280° F)

No limit (Transient only)

None

693-749° C (1280-1380° F)

Until stabilized (5 min max)

None

749-843° C (1380-1550° F)

0 to 6 sec (intentional use of tem-

None

peratures in excess of 749°C

(1380° F) is not recommended)

749-843° C (1380-1550° F)

Over 6 sec

Inspect turbine (2)

843-927° C (1550-1700° F)

Not allowed (3)

Inspect turbine (2)

Over 927° C (1700° F)

Not allowed (3)

Remove turbine for heavy mainte-

nance or overhaul.

(1) Applicable only in multi-engine helicopters when meeting one engine inoperative climb requirements.

(2) Refer to the Special Inspections Section III, Table 9, Item 11 or 13. Also, record temperature and duration

in the Engine Log Book (pink pages, Turbine Assembly Part IV, Inspection Record).

Page 3

(3) Momentary peak temperature of 927°C (1700°F) is permitted for no more than one second.

NOTE: The time-at-temperature limits are not additive. The repeated, intentional use of transient

temperature limits can result in reduced turbine life and is not recommended.

Torque

A. If max torque limit of 365 hp (273 kW)-320 lb ft (434 N^.m) is exceeded for more than 10 seconds,

the gearbox must be removed and sent to an Authorized Maintenance Center to be overhaul

inspected. Refer to FIG. 2 for torquesensor oil pressure-to-shaft power relationship and to Table 2

for torque limits.

TABLE 2

Output Shaft Torque Limit

Torque

Pressure

Power

Time Limit

lb ft

N^.m psi

kPa hp

320

434

109

752

365

273

10 sec

293

397

100

689

335

250

30 min

249

337

586

284

212

Continuous

Oil Pressure and Temperature

If the oil pressure is not within the following limits, refer to Section III, Table 6, Troubleshooting.

a. 97% N₁ speed and above

110-130 psig (758-896 kPa)

78 to 97% N₁ speed

90-130 psig (621-896 kPa)

c. Below 78% N₁ speed

50 psig min (345 kPa)

d. During start

a positive indication must be obtained

when 59% (idle) is reached.

NOTE: During cold weather operation, 150 psig (1034 kPa) main oil pressure is allowable

following an engine start. When the 130 psig (896 kPa) limit is exceeded, operate engine

at minimum power until normal oil pressure limits are attained.

NOTE: If the engine has been operated with less than the required oil pressure, except for

momentary fluctuation, inspect the oil system in accordance with Low Oil Pressure

Operation, Section III.

Oil temperature shall be within the following range. (If the maximum limit is exceeded, refer to Oil

Temperature Limit Exceeded, Section III, for corrective action.)

a. Minimum starting

MIL-PRF-7808F or later

-54°C

(-65°F)

MIL-PRF-23699

-40°C

(-40°F)

b. Maximum

107°C

(225°F)

c. Minimum flight operation

0°C

(32°F)

(Providing engine oil pressure is within the specified limits of para 7 a.)

Pressure Altitude And Ambient Temperature

A. The engine will start and operate satisfactorily at conditions of ambient pressure and temperature

as shown in FIG. 3.

Page 4

Engine Operating Procedures

WARNING: TO PREVENT ENGINE FUEL STARVATION AND SUBSEQUENT FLAMEOUT, ANY

AIRCRAFT REQUIRING FUEL BOOST PUMP(S) SHOULD USE THESE PUMPS AT

ALL TIMES DURING FLIGHT OR AS DIRECTED IN THE AIRCRAFT FLIGHT MANUAL.

WARNING: TO PREVENT CRUCIAL DELAY IN REGAINING POWER IF AN ENGINE FLAMEOUT

IS ENCOUNTERED, AIRCRAFT EQUIPPED WITH AN AUTO-RELIGHT SYSTEM

SHOULD KEEP THAT SYSTEM ACTIVATED AT ALL TIMES WHILE THE AIRCRAFT IS

IN FLIGHT.

A. Start and Ground Idle

The following procedures pertain to operation of the engine at: start and ground idle; power range;

practice autorotation, descent and landing; stopping; and during an emergency.

WARNING: TO ENSURE ADEQUATE WARNING OF POSSIBLE EMERGENCY ENGINE

OPERATING CONDITIONS, VERIFY THAT THE ENGINE WARNING SYSTEMS

(ENGINE-OUT HORN, FILTER BYPASS LIGHT, AND CHIP DETECTOR LIGHT) ARE

OPERABLE BEFORE EACH FLIGHT.

WARNING: OVERTEMPERATURE STARTS OR AFTERFIRES AFTER SHUTDOWN WILL CAUSE

CRACKS IN THE 1ST-STAGE WHEEL RIM. THESE CRACKS CAN EVENTUALLY

CAUSE A SECTION OF THE WHEEL TO BREAK OUT AND EXIT THE ENGINE WITH

POTENTIALLY DISASTROUS RESULTS.

NOTE: For the ultimate safety of all personnel who come in close proximity with the engine in the

future, it is the responsibility of the pilot and maintenance personnel to record and take

recommended corrective action when an overtemperature occurs.

CAUTION: BEFORE THE ENGINE IS OPERATED, MAKE CERTAIN THE COMPRESSOR

INLET IS FREE OF DEBRIS. ALSO, MAKE CERTAIN THE COMPRESSOR

ROTOR IS NOT FROZEN, IF THE AIRCRAFT IS IN A FREEZING ATMOSPHERE.

Preflight Inspections. Before starting the engine, make a preflight inspection. (Refer to Preflight

and Postflight Inspections, Section III, Table 7.)

(1) Two starting procedures are provided for the engine. The first procedure is for normal starts in

ambient temperatures above 4°C (40°F). (Refer to Normal Start Procedure sub-para 2.) The

second procedure is for starts in ambient temperatures between plus 4° and minus 54°C (39°

and minus 65°F). (Refer to Cold Weather Start Procedure, sub-para 3.)

(2) Normal Start Procedure. Start the engine as follows:

(a) Rotate the twist grip to FUEL OFF and turn all switches off.

(b) Position the aircraft collective pitch (load) control in the minimum position.

NOTE: It is recommended that the residual TOT be no more than 150°C (302°F) when

the throttle is opened and light off is attempted. Residual TOT can be readily

reduced to or below 150°C (302°F) by motoring engine with the starter.

CAUTION: DURING A START, THE TWIST GRIP MUST NEVER BE ROTATED OUT OF

THE FUEL OFF POSITION UNTIL AFTER THE STARTER AND IGNITION

EXCITER HAVE BEEN ENERGIZED AND THE DESIRED CRANKING SPEED

HAS BEEN ATTAINED. TO DO SO MIGHT RESULT IN AN EXPLOSIVE

LIGHTOFF OR OVERTEMPERATURE START.

Page 7

CAUTION: AN ENGINE FIRE (WITH THE RESULTANT FLAME EMANATING FROM THE

TAILPIPE), CAN OCCUR DURING START IF THE COMBUSTION CHAMBER

BECOMES OVERLOADED WITH FUEL BEFORE IGNITION TAKES PLACE.

TO EXTINGUISH THE FIRE, CONTINUE TO MOTOR THE ENGINE USING

THE STARTER WITH THE THROTTLE FULLY CLOSED AND THE MAIN

FUEL SWITCH OFF.

CAUTION: MONITOR OIL PRESSURE DURING START. DAMAGE TO ROTOR

BEARINGS CAN RESULT IF A POSITIVE INDICATION OF OIL PRESSURE

IS NOT OBTAINED BY THE TIME IDLE SPEED IS REACHED.

(d) Energize the starter motor and ignition exciter.

CAUTION: A START SHOULD NOT BE ATTEMPTED AT N₁ SPEEDS BELOW 12%.

STARTING AT N₁ SPEEDS LESS THAN 12% INCREASES THE

POSSIBILITY OF EXCEEDING ENGINE TEMPERATURE LIMITS.

CAUTION: FOR ENGINES INCORPORATING LOW ENERGY EXCITERS,

OPERATING TIME LIMITS ARE AS FOLLOWS: 2 MINUTES ON, 3

MINUTES OFF; 2 MINUTES ON, 23 MINUTES OFF.

CAUTION: HIGH ENERGY IGNITION EXCITERS ARE QUALIFIED FOR

CONTINUOUS DUTY OPERATION. HOWEVER, USE OF THE

IGNITION SYSTEM ON A CONTINUOUS BASIS IS NOT

RECOMMENDED BECAUSE OF DEGRADATION OF THE SPARK

IGNITER.

(e) As N₁ rpm accelerates through 12-15% N₁, move the twist grip to the IDLE position to

begin fuel flow.

NOTE: Do not wait for N₁ peak out. Introduce fuel immediately upon reaching desired

N₁ speed. Delay in moving the throttle to the idle detent may diminish battery

capacity early in the start cycle.

NOTE: It is recommended that residual TOT be no more than 150°C (302°F) when the

throttle is opened and lightoff is attempted. Residual TOT can be readily

reduced to or below 150°C (302°F) by motoring the engine with the starter.

CAUTION: IF THE N₂ TURBINE IS NOT ROTATING BY 25% N₁ SPEED ABORT THE

START. A SECOND OR THIRD START ATTEMPT MAY BE MADE; IF THE

CONDITION STILL EXISTS REFER TO SECTION III, TROUBLESHOOTING

TABLE 6, ITEM 58.

CAUTION: IF THE ENGINE HAS BEEN SHUT DOWN FOR MORE THAN 15 MINUTES,

STABILIZE AT IDLE SPEED FOR ONE MINUTE BEFORE INCREASING

POWER.

(f)

De-energize the starter and ignition exciter when 58% N₁ speed is reached. The start is

completed when a stabilized N₁ speed of 59-65% is reached. Completion of the start

normally occurs 25 to 60 seconds after starter engagement. A positive indication of oil

pressure must be obtained by this point in the start. If it is not, shut down the engine and

check to be sure that oil is available at the power and accessories gearbox inlet. Mon-

itor the measured gas temperature; do not exceed the limits of Table 1.

NOTE: If a stagnated start is experienced, shut down then repeat start procedure.

NOTE: If overtemperature is experienced, turn the twist grip to FUEL OFF and motor

the engine without ignition for ten seconds.

NOTE: The start should be complete in one minute; however, if N₁ and N₂ are

accelerating and TOT is within limits, the start may be continued longer than

one minute.

NOTE: Monitor N₁, and TOT when turning generator switch ON. If N₁ decays below 60

percent, or TOT approaches 810°C (1490°F), turn generator OFF and increase

N₁ speed with throttle to 70 percent, then reset generator to ON.

Page 8

(3)

Cold Weather Start Procedure. Some general practices recommended for improved cold

weather operation of the 250-C18 series engines are as follows:

(a) When the aircraft is parked, use appropriate covers over the inlet ducts, exhaust stacks,

etc.

(b) At temperatures below 40°F (4°C), use JP-4 or commercial Jet B fuel if available. As an

alternate, use the AVGAS-jet fuel mixture described in Cold Weather Fuels, para 10.

NOTE: Use fuel containing an anti-ice additive whenever engine operations are

conducted below 4°C (40°F).

CAUTION: DO NOT USE AN OPEN FLAME HEATER TO PREHEAT THE ENGINE OR

BATTERY.

auxiliary power source for faster more satisfactory starts, if equipment is available and

conditions allow,.

(d) If the aircraft has been cold soaked at temperatures below minus 18°C (0°F) and a

battery start must be made, preheat the engine fuel control area and battery if equipment

is available and conditions allow.

(e) If the aircraft has been cold soaked and a battery start must be made without preheating

the battery, remove and store the battery until it is required if conditions allow. Store the

battery in an area where it can be maintained or warmed to a temperature above ambient

outside conditions or to approximately 21°C (70°F).

(f)

If stagnated starts are encountered, enrich the starting fuel flow in accordance with the

start derichment adjustment procedure in Fuel Control Adjustments, Section III .

(4)

During cold weather, start the engine as follows:

(a) Rotate the twist grip to FUEL OFF and turn all switches off.

(b) Position the aircraft collective pitch (load) control in the minimum position.

CAUTION: DURING A START, TWIST GRIP MUST NEVER BE ROTATED OUT OF THE

FUEL OFF POSITION UNTIL AFTER THE STARTER AND IGNITION

EXCITER HAVE BEEN ENERGIZED AND THE DESIRED CRANKING SPEED

HAS BEEN ATTAINED. TO DO SO MIGHT RESULT IN AN EXPLOSIVE

LIGHTOFF OR OVERTEMPERATURE START.

CAUTION: AN ENGINE FIRE (WITH RESULTANT FLAME EMANATING FROM THE

TAILPIPE) CAN OCCUR DURING START IF THE COMBUSTION CHAMBER

BECOMES OVERLOADED WITH FUEL BEFORE IGNITION TAKES PLACE.

TO EXTINGUISH THE FIRE, CONTINUE TO MOTOR THE ENGINE USING

THE STARTER, WITH THE THROTTLE FULLY CLOSED AND THE MAIN

FUEL SWITCH OFF.

CAUTION: MONITOR OIL PRESSURE DURING START. DAMAGE TO ROTOR

BEARINGS CAN RESULT IF A POSITIVE INDICATION OF OIL PRESSURE

IS NOT OBTAINED BY THE TIME IDLE SPEED IS REACHED.

(d) Energize the starter motor and ignition exciter.

CAUTION: A START SHOULD NOT BE ATTEMPTED AT N₁ SPEEDS BELOW 12%.

STARTING AT N₁ SPEEDS LESS THAN 12% INCREASES THE POSSIBILITY

OF EXCEEDING ENGINE TEMPERATURE LIMITS.

CAUTION: FOR ENGINES INCORPORATING LOW ENERGY EXCITERS, OPERATING

TIME LIMITS ARE AS FOLLOWS: 2 MINUTES ON, 3 MINUTES OFF; 2

MINUTES ON, 23 MINUTES OFF.

CAUTION: HIGH ENERGY IGNITION EXCITERS ARE QUALIFIED FOR CONTINUOUS

DUTY OPERATION. HOWEVER, USE OF THE IGNITION SYSTEM ON A

CONTINUOUS BASIS IS NOT RECOMMENDED BECAUSE OF

DEGRADATION OF THE SPARK IGNITER.

(e) At the desired N₁ cranking speed, rotate the twist grip to the IDLE position. Use the

following guide for desired N₁ starting speed versus outside air temperature.

N₁ rpm %

Temperature ° F

(° C)

Above 45

0 to 44

-18 to +7

Below -1

-18

NOTE: Due to the variation in jet fuels available for commercial operation, in cold

weather the engine may experience a short delay before lightoff after the twist

grip is rotated to the IDLE position. This delay should be less than three

seconds regardless of the type of fuel used. If the lightoff delay exceeds three

seconds, return the twist grip to FUEL OFF and continue to motor the engine

with the starter for thirty seconds to remove excess fuel from the combustion

section.

(f)

De-energize the starter and ignition exciter when 58% N₁ speed is reached. The start is

completed when a stabilized N₁ speed of 59 to 65% is reached. Completion of the start

normally occurs 25 to 60 seconds after starter engagement.

CAUTION:

A POSITIVE INDICATION OF OIL PRESSURE MUST BE OBTAINED BY THIS

POINT IN THE START. IF IT IS NOT, SHUT DOWN THE ENGINE AND

CHECK TO BE SURE THAT OIL IS AVAILABLE AT THE POWER AND

ACCESSORIES GEARBOX INLET.

CAUTION:

MONITOR MEASURED GAS TEMPERATURE. DO NOT EXCEED THE

LIMITS OF TABLE 1. IF OVERTEMPERATURE IS EXPERIENCED, TURN

THE TWIST GRIP TO FUEL OFF AND MOTOR THE ENGINE WITHOUT

IGNITION FOR 10 SECONDS.

CAUTION:

IF THE MAIN ROTOR IS NOT ROTATING BY 25% N₁ SPEED ABORT THE

START. A SECOND OR THIRD START ATTEMPT MAY BE MADE; IF THE

CONDITION STILL EXISTS. REFER TO SECTION III, TROUBLESHOOTING,

TABLE 6, ITEM 58.

CAUTION:

IF THE ENGINE HAS BEEN SHUT DOWN FOR MORE THAN 15 MINUTES,

STABILIZE AT IDLE SPEED FOR ONE MINUTE BEFORE INCREASING

POWER.

NOTE:

In some instances N₁ may accelerate slowly through the 25-30% speed range

on a battery start after an engine has been cold soaked and not preheated. If

the start is not completed within the starter engagement time limits, shut down

the engine. Before attempting the next start, wait for the starter duty cycle limits

to pass or for one minute, whichever is longer. This wait will allow residual heat

from the previous start attempt to soak back into the engine and battery that

improve conditions for the next start attempt.

Page 10

Power Range

CAUTION: BE SURE THE N₂ SPEED RESTRICTIONS GIVEN IN POWER TURBINE SPEED

RESTRICTIONS, PARA 4 ARE OBSERVED.

CAUTION: DECREASING COLLECTIVE TO THE LOW POWER RANGE WILL RESULT IN AN

N₂/N_R INCREASE. IF THE RPM IS RESET WITH THE BEEP SWITCH, LOW

N₂/N_R RPM CAN RESULT WHEN COLLECTIVE IS INCREASED TO THE HIGH

POWER RANGE UNLESS THE BEEP SWITCH SETTING IS RETURNED TO

NEAR THE PREVIOUS BEEP POSITION.

(1) During operation in the power range place the twist grip in the maximum position and utilize

engine power with the collective pitch. Vary the pitch to avoid exceeding the measured gas

temperature and torque limits given in Tables 1 and 2 or the N₂ speed limit given in FIG. 1. It

is recommended that large collective increases be made over a 2 second time period to avoid

momentary N₂/N_R droop.

Augmented Takeoff

CAUTION: AUGMENTED TAKEOFFS ARE LIMITED TO AMBIENT TEMPERATURES ABOVE

4°C (40°F) AND SHALL NOT EXCEED FIVE MINUTES IN DURATION.

(1) Operation of Water-Alcohol System.

(a) Make a normal engine start. Idle the engine one minute before increasing power.

CAUTION: DO NOT MAKE RAPID POWER DECELERATIONS OR OPERATE N₂ AT

LESS THAN 95% SPEED WHILE USING WATER-ALCOHOL

AUGMENTATION.

(b) Rotate twist grip to full open and increase TOT to 693°C (1280°F) then turn on the

water-alcohol system. (Power will remain steady while the TOT will decrease.) Adjust

power to desired setting but do not exceed 749°C (1380°F) or the maximum torque limit.

NOTE: Acceleration time to augmented Takeoff power will require approximately two

seconds more than acceleration time to nonaugmented Takeoff power.

Practice Autorotation Descent And Landing

NOTE: If there is any doubt that the deceleration check was made during shutdown after the last

flight of the previous day, make the decel check before initiating a practice autorotation.

(Refer to Section III, Preflight and Postflight Inspections, Table 7, item 7.)

CAUTION: BEFORE INITIATING A PRACTICE AUTOROTATION, ENSURE THAT A

DECELERATION CHECK WAS MADE AFTER THE LAST FLIGHT OF THE

PREVIOUS DAY. FAILURE TO MAKE A DECELERATION CHECK COULD CAUSE

ENGINE FLAMEOUT.

(1) Practice autorotation landings are made as follows:

(a) For autorotation descent the twist grip may be in any position. However, if practice

autorotation landing (minimum engine power) is desired, rotate the twist grip to the IDLE

position.

(b) The twist grip must be rotated to maximum to make full engine power available upon

demand.

NOTE: N₂ instability may be encountered during practice autorotation. This is a normal

condition when in autorotation.

Air Restart

(1) The following air start procedures apply to either starts made during an emergency or to starts

made during normal restart conditions:

Page 11

CAUTION: IF ENGINE MECHANICAL FAILURE IS SUSPECTED, AN AIR RESTART SHOULD

NOT BE ATTEMPTED.

(a) Emergency Restart. When immediate power restoration is required, make an

emergency air restart by energizing the starter within 10 seconds after power loss occurs.

NOTE: N₁ will not decrease below minimum starting speed within the 10 seconds

because of rotational inertia plus possible ram effect. The Throttle or Power

Lever can be left in the open position since fuel flow during the start will be on

the normal acceleration schedule.

CAUTION: DUE TO THERMAL CHANGES WITHIN THE TURBINE, THE GAS

PRODUCER SECTION OF THE ENGINE MAY LOCK UP AFTER AN

IN-FLIGHT SHUTDOWN. THIS IS A TEMPORARY CONDITION WHICH

EXISTS AFTER THE ENGINE HAS BEEN SHUT DOWN FOR

APPROXIMATELY ONE MINUTE AND WHICH MAY CONTINUE FOR UP TO

TEN MINUTES FOLLOWING THE SHUTDOWN. THEREFORE, EXCEPT

DURING AN EMERGENCY, AIR STARTS SHOULD NOT BE ATTEMPTED

DURING THE TIME PERIOD BETWEEN ONE MINUTE AFTER SHUT-DOWN

AND TEN MINUTES AFTER SHUTDOWN.

(b) Normal Restart. Make a normal restart as follows:

With the throttle (Power Lever) in FUEL OFF, energize the starter and ignition

exciter.

At the desired N₁ speed (or above) position the throttle (Power Lever) in the full open

position. Use the following guide to determine desired N₁ starting speed versus

outside air temperature.

Starting Speed vs OAT

N₁ rpm %

Temperature ° F

(° C)

Above 45

0 to 44

-18 to +7

Below -1

-18

De-energize the starter at 58% N₁ speed.

Apply collective pitch as required.

Anti-icing Air

(1) Use anti-icing air when any of the following conditions are encountered:

(a) When flying into visible moisture at temperatures below 2°C (35°F) at the engine inlet.

(Consult the Aircraft Operating Manual for the ambient temperature at which anti-icing air

should be used.)

(b) During the drying run following compressor rinse or wash operations. (Refer to Section

III, Compressor Cleaning, or Compressor Salt Water Contamination Removal.)

1-2 minutes every 25 hours purges dirt and debris from the anti-ice air passages of the

compressor front support.

Stopping

NOTE: For the ultimate safety of all personnel who come in close proximity with the engine in the

future, it is the responsibility of the pilot and maintenance personnel to record and take

recommended corrective action when overtemperature occurs.

WARNING: OVERTEMPERATURE STARTS OR AFTERFIRES AFTER SHUTDOWN WILL

CAUSE CRACKS IN THE 1ST-STAGE WHEEL RIM. THESE CRACKS CAN

EVENTUALLY CAUSE A SECTION OF THE WHEEL TO BREAK OUT AND EXIT

THE ENGINE WITH POTENTIALLY DISASTROUS RESULTS.

(1) Stop the engine as follows:

Page 12

(a) Rotate the twist grip to the IDLE position.

WARNING: IDLE DWELL TIME PRIOR TO SHUTDOWN IS IMPORTANT TO PREVENT

HARMFUL ACCUMULATION OF CARBON IN THE ENGINE, WHICH CAN

RESULT IN ENGINE FAILURE.

(b) Maintain the engine at 59-65% N₁ speed for a minimum of two minutes prior to shutdown.

(d) Turn off all engine switches.

CAUTION: AN ENGINE FIRE (RECOGNIZED BY A RAPID INCREASE IN TOT) CAN

OCCUR DURING SHUTDOWN IF FUEL CUTOFF IS NOT COMPLETE. IF A

SHUTDOWN FIRE OCCURS, IMMEDIATELY ENGAGE THE STARTER AND

MOTOR THE ENGINE TO MINIMIZE THE TEMPERATURE ENCOUNTERED.

TO EXTINGUISH THE FIRE, CONTINUE TO MOTOR THE ENGINE USING

THE STARTER WITH THE THROTTLE FULLY CLOSED AND THE MAIN

FUEL SWITCH OFF. THE TEMPERATURE LIMITATIONS AND

MAINTENANCE ACTION IN TABLE 1 MUST BE OBSERVED.

(e) Monitor instrumentation to ensure that shutdown has occurred. To assure throttle cutoff,

hold the throttle in the closed position until N₁ speed is zero and TOT has stabilized.

NOTE: A deceleration check is recommended during the shutdown for the last flight of

each day. Refer to Fuel Control Operational Checks, Section III.

Alternate Shutdown

(1) Use the following alternate shutdown procedure when operational conditions such as high

winds require 100% N₂ (rotor speed) during the dwell period following flight.

WARNING: DWELL TIME AT MINIMUM POWER BEFORE SHUTDOWN IS IMPORTANT TO

PREVENT HARMFUL ACCUMULATION OF CARBON IN THE ENGINE. CARBON

BUILDUP CAN RESULT IN ENGINE FAILURE.

(a) Position the collective and cyclic controls at the minimum power settings consistent with

operational safety requirements.

(b) Stabilize the engine for a minimum of 2 minutes at minimum power.

NOTE: It is not necessary to pause at the Idle position except to perform the

deceleration check during shutdown for the last flight of each day.

(d) Turn off all engine switches.

CAUTION: AN ENGINE FIRE (RECOGNIZED BY A RAPID INCREASE IN TOT) CAN

OCCUR DURING SHUTDOWN IF FUEL CUTOFF IS NOT COMPLETE. IF A

SHUTDOWN FIRE OCCURS, IMMEDIATELY ENGAGE THE STARTER AND

MOTOR THE ENGINE TO MINIMIZE THE TEMPERATURE ENCOUNTERED.

TO EXTINGUISH THE FIRE, CONTINUE TO MOTOR THE ENGINE USING

THE STARTER WITH THE THROTTLE FULLY CLOSED AND THE MAIN

FUEL SWITCH OFF. THE TEMPERATURE LIMITATIONS AND

MAINTENANCE ACTION IN TABLE 1 MUST BE OBSERVED.

(e) Monitor instrumentation to ensure that shutdown has occurred. To ensure throttle cutoff,

hold the throttle in the closed position until N₁ speed is zero and TOT has stabilized.

NOTE: A deceleration check is recommended during the shutdown for the last flight of

each day. (Refer to Section III, Deceleration Check.)

Postflight Inspection

(1) Following the last flight of the day, conduct a postflight inspection.

(Refer to Preflight and

Postflight Inspections, Section III, Table 7.)

Page 13

Emergency

(1) If the power turbine governor should fail to function, resulting in a rapid N₂ speed increase,

reduce the throttle setting to control overspeed.

(2) Manipulate the collective pitch to control the helicopter.

(3) Monitor the N₂ speed and vary the throttle setting to maintain desired speed.

NOTE: The same power range is available using the throttle in an emergency as in normal

power turbine governing.

(4) The power turbine governor can also fail in a decrease fuel flow condition. This can be

recognized by decreased N₁ speed and decreased torque output with the throttle in the full

open position. In this event, initiate autorotation.

10.

Cold Weather Fuels

WARNING: AT AMBIENT TEMPERATURES BELOW 4°C (40°F), SOME TYPE OF ANTI-ICE

PROTECTION IS REQUIRED, SUCH AS AN ANTI-ICE ADDITIVE OR A MEANS OF

AIRFRAME FUEL ICE ELIMINATION. ENGINE FLAMEOUT COULD RESULT FROM

FAILURE TO USE ANTI-ICE PROTECTION. (REFER TO THE AIRCRAFT MANUAL

FOR THEIR REQUIREMENTS. REFER TO SECTION 1, FUEL SPECIFICATIONS FOR

APPROVED ANTI-ICE ADDITIVE.)

A. The fuels recommended for consistent cold weather starting, 4°C (40°F) and below, are as follows:

(1) JP-4 (MIL-T-5624)

(2) Jet B (ASTM D-1655)

(3) AVGAS/Jet A, A-1, or JP-5 mixture

NOTE: JP-4, JP-5 and JP-8 type fuels conforming to MIL-T-5624 or MIL-T-83133A or later

contain an anti-ice additive which conforms to MIL-I-27686 or later and do not require

additional anti-ice additives unless specified by the airframe manufacturer.

NOTE: Jet A, Jet A-1, or JP-5 may start the engine at temperatures below 4°C (40°F);

however, when cold soaked marginal starts may result due to viscosity changes.

NOTE: Once started, the engine will operate satisfactorily on JP-5, JP-8, Jet A and Jet A1

at fuel and outside air temperatures down to -32°C (-25°F).

11.

Mixing Alternate Cold Weather Fuels

CAUTION: AVGAS MUST NEVER BE MIXED WITH JP-4 OR COMMERCIAL JET B FUELS.

A. The alternate cold weather fuel mixture shall consist of one part by volume AVGAS and two parts

by volume commercial jet fuel. The AVGAS shall conform to MIL-G-5572C, grade 80/87, or grade

100/130 with 2.0 ml/gal max lead content. Do not use grade 100/130 with 4.6 ml/gal lead content.

(The 2.0 ml/gal lead, grade 100/130, AVGAS is known as 100L AVGAS in European areas.) The

commercial jet fuel may be kerosene; JP-5; or commercial Jet A conforming to MIL-T-5624, grade

JP-5 or ASTM D-1655, Jet A or A1.

CAUTION: THERE IS NO TIME LIMIT FOR ENGINE OPERATION USING THE AVGAS-JET FUEL

MIXTURE AS LONG AS 80/87 GRADE AVGAS IS USED AND THE 1:2 VOLUME RATIO

IS OBSERVED. USE OF 100/130 (100L) GRADE AVGAS-JET FUEL MIXTURE SHALL

BE RESTRICTED TO 300 HOURS IN ONE OVERHAUL PERIOD DUE TO THE HIGH

LEAD CONTENT OF THE FUEL.

NOTE: Use of 100/130 (100L) grade AVGAS and jet fuel mixture shall be restricted to 300 hours

in one overhaul period due to the high lead content of the fuel. Prolonged and

uninterrupted operation with the AVGAS mixture will induce lead buildup on turbine parts.

This lead buildup can cause a gradual power reduction; consequently, this AVGAS

mixture should be used only for cold weather operation. During operation with normal Jet

A or Jet B type turbine fuel, lead buildup will slowly dissipate.

Page 14

Rolls-Royce Engine 250–C18, 250–C18A, 250–C18B, 250–C18C. Operation and Maintenance Manual (2003) - page 2