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

CAUTION: AN OVER ADJUSTMENT OF THE START/ACCELERATION CCW SETTING

CAN CAUSE A DECREASE IN STARTING TIME TO A POSSIBLE HUNG

START.

(d) When the final start/acceleration adjuster position is established, lockwire the pointer in

accordance with FIG. 16.

(e) Check idle speed and deceleration time after the final start setting is determined. (Refer

to Fuel Control Idle Speed Setting, and Engine Deceleration Check.)

47. Gas Producer Fuel Control Fuel Strainer Cleaning.

A. Remove, clean, and reinstall the Bendix fuel control fuel strainer as follows: (Ref. FIG. 18)

(1) Remove lockwire from the plug.

NOTE: Thoroughly clean the exterior of the fuel control in the area of the plug to prevent

contaminants from getting into the port after it is opened.

(2) Remove the plug, spring, and filter assembly from the fuel control. Discard the O-ring.

(3) Remove the clip and spring pin. Separate the washer, spring ,and strainer assembly from the

filter sleeve.

1. Plug

2. O-ring

2A.Spring

3. Filter Assembly

4. Spring Pin

5. Washer

6. Spring

7. Strainer Assembly

8. Filter Sleeve

9. Clip

Fuel Control Strainer Removal

FIG. 18

NOTE: The fuel control strainer assembly must be replaced at periodic intervals. Inspect

removed strainer assembly for contamination prior to discarding.

(4) Clean the filter assembly parts ultrasonically if equipment is available. If equipment is not

available, agitate the parts in mineral spirits. Dry parts using clean shop air regulated to

approximately 15 psig (103 kPa). Air pressure should be applied to the exterior of the strainer.

Repeat the procedure if visual inspection with a bright light shows that the interior of the

strainer is not entirely free of contaminants.

Page 103

CAUTION: FUEL FLOW DIRECTION THROUGH THE STRAINER IS FROM THE INSIDE TO

THE OUTSIDE. ENSURE THAT THE INSIDE OF THE STRAINER IS FREE OF

CONTAMINATION.

CAUTION: DO NOT ATTEMPT TO OPEN A CLOGGED SCREEN WITH A SHARP

INSTRUMENT.

(5) The following cleaning procedure may be used as an alternate if the method described in step

(4) does not clean the strainer assembly satisfactorily.

WARNING: SULPHURIC ACID CAUSES SEVERE BURNS. DO NOT GET IN EYES, ON SKIN,

OR ON CLOTHING. DO NOT ADD WATER TO ACID WHILE IN A CONTAINER

BECAUSE OF VIOLENT REACTION. IN THE EVENT OF CONTACT WITH

SULPHURIC ACID, IMMEDIATELY FLOOD EXPOSED SKIN OR CLOTHING WITH

WATER. FOR EYES, FLUSH HEAVILY WITH WATER AND OBTAIN IMMEDIATE

MEDICAL ATTENTION.

(a) Immerse the strainer assembly in sulfuric acid (specific gravity 1.82 to 1.84) containing

approximately 20 grams of sodium dichromate per liter (0.2642 U.S. gallon) for a period of

two to five minutes at room temperature.

(b) Rinse in hot running water and dry with a hot air blast.

CAUTION: BE SURE THE STRAINER ASSEMBLY IS INSTALLED AS SHOWN IN FIG. 18

WITH THE OPEN END TOWARD THE OUTSIDE OF THE CONTROL, AWAY

FROM THE SPRING. DO NOT INSTALL BACKWARDS.

(6) Reassemble the strainer, spring, and washer in the filter sleeve. Secure the components in

the sleeve with the spring pin and clip.

(7) Lightly lubricate a new O-ring (Bendix P/N 557S6) with engine fuel and place it on the plug.

Install the filter assembly, spring and plug in the fuel control. Torque plug to 65-70 lb in.

(7.3-7.9 N^.m) and secure with lockwire.

NOTE: If the old O-ring must be reused, dry it under a heat lamp to restore dimensions.

48.

Gas Producer Fuel Control Replacement

A. Replace the fuel control assembly if it is found to be the cause of engine malfunction.

CAUTION: USE EXTREME CARE TO ENSURE THAT THE PNEUMATIC LINES AND FITTINGS

ARE NOT LEAKING. ERRONEOUS PRESSURES WILL CAUSE FUEL CONTROL

MALFUNCTION.

B. Remove the gas producer fuel control from the engine as follows: (Ref. FIG. 8, 9, and 10)

CAUTION: WHEN THE FUEL CONTROL IS BEING REMOVED USE EXTREME CARE TO

PREVENT FOREIGN MATERIALS FROM ENTERING THE PNEUMATIC LINES OR

FUEL CONTROL PORTS.

(1) Remove the linkage connections, fuel and air lines.

(2) Remove three nuts and washers which secure the control to the power and accessories

gearbox housing.

(3) Carefully remove the control.

CAUTION: WHEN REMOVING OR INSTALLING FITTINGS, BE CAREFUL NOT TO CAUSE A

LOAD ON THE FUEL CONTROL DRIVE SHAFT. USE THE WOODEN

PROTECTIVE SHIPPING BLOCK TO PROTECT THE SHAFT FROM THE WORK

BENCH.

(4) If the unit is to be replaced, remove all fittings necessary for installation of the replacement

unit.

(5) Drain residual fuel from the rejected fuel control and fill the inlet and bypass ports with oil

(Atlantic Refining Co. 31100, or equivalent). Open the cutoff valve, using the gas producer

lever, and fill the outlet port with oil. Cap the inlet, bypass, and cutoff ports.

Page 104

NOTE: In installations where the gas producer lever is not required, remove the lever from

the replacement fuel control and install it on the control being returned for overhaul.

Install the gas producer fuel control on the engine as follows:

NOTE: Before installing the Bendix fuel control on the engine, install the required fittings:

(1) Remove and discard all old packings.

(2) Lubricate new packings and install on the fittings.

(3) Install the fuel inlet and fuel bypass unions. Torque to 75-110 lb in. (8.5-12.4 N^.m).

(4) Install the P_g union. Torque to 55-80 lb in. (6.2-9.0 N^.m).

(5) If required, install the P_y union. Torque to 55-80 lb in.

(6) Install Pr elbow and jam nut. Do not torque jam nut at this time.

NOTE: Use the wooden protective shipping block to protect the shaft from the work bench

when installing the fittings.

(7) Coat fuel control drive shaft with Lubriplate 130A, 930AA, or equivalent, the studs with

antiseize compound and fuel fittings with oil (Atlantic Refining Co. 31100, or equivalent).

CAUTION: BE CERTAIN THAT THE CONTROL DRIVE PILOT IS PROPERLY INSERTED IN

THE GEARBOX.

WARNING: FAILURE TO PROPERLY INSTALL, ALIGN, AND TORQUE FUEL, OIL, AIR

FITTINGS AND TUBES COULD RESULT IN AN ENGINE FAILURE.

(8) Install in reverse of removal.

NOTE: Make sure the procedures and precautions of Rigid Tube Installation, are observed

when installing fuel system tubes and aligning elbow.

NOTE: Hold fuel control fittings with one wrench while tightening “B” nut to fitting with

another wrench.

(9) Torque mount pad nuts to 70-85 lb in. (7.9-9.6 N^.m).

(10) Torque fuel inlet and bypass lines coupling nuts to 150-200 lb in. (17-23 N^.m).

(11) Torque fuel outlet line coupling nut to 80-120 lb in. (9.0-13.6 N^.m).

(12) Torque fuel control air line coupling nuts to 80-120 lb in. (9.0-13.6 N^.m).

(13) Torque elbow jam nut 55-80 lb in. (6.2-9.0 N^.m).

(14) Check the fuel control lever travel using the cockpit control. The lever stop arm on the fuel

control must bottom out on the maximum and minimum speed stops. (Refer to Fuel Control

Rigging Check.)

NOTE: During rigging of the linkage, the primary points of significance are the 30-degree

mark and full travel, minimum stop to maximum stop. Ground Idle position is

established with the pointer at the 30-degree mark on the quadrant.

CAUTION: OVERTORQUING CAUSES BINDING OF THE LEVER SHAFT.

(15) If the gas producer lever requires repositioning--loosen the nut, reposition, then torque the nut

to 40-60 lb in. (4.5-6.8 N^.m).

(16) After the gas producer fuel control has been replaced, bleed air from the fuel system. (Refer

to Fuel System Air Purging.)

(17) Check the max. N₁ speed setting of the replacement fuel control. (Refer to Checking the Fuel

Control Max. Speed Stop.)

(18) Perform a Fuel System Pneumatic Leak Check.

(19) Check run the engine after fuel control replacement. (Refer to Engine Check Run.)

Page 105

NOTE: After the fuel control has been changed, if a false start is encountered or a start is

not completed in one minute, return the gas producer lever to FUEL OFF. Motor the

engine without ignition for 10 seconds before attempting another start.

(20) Make a fuel control operational check. (Refer to Fuel Control Operational Checks.)

(21) Make appropriate entry relative to fuel control replacement in the Engine Log.

49.

Fuel Control Operational Checks

A. Ground check the control system and associated linkage by making a deceleration check.

Corrective action for an improper deceleration rate shall be as follows:

NOTE: Perform the steps of the corrective action in the sequence listed. Recheck the

deceleration rate after each step to determine if there is a need for further correction.

Replace the fuel control if the deceleration rate is still unsatisfactory after all steps of the

corrective action have been completed.

(1) Check rigging. (Refer to Fuel Control Rigging Check.)

(2) Check idle speed setting. (Refer to Fuel Control Idle Speed Setting.)

(3) Clean the P_c filter, P_x and P_y bleeds. (Refer to the Fuel Control Air Circuit Cleaning .)

50.

Engine Deceleration Check

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

NOTE: The allowable deceleration times are for an engine which is at normal operating

temperature. Perform the deceleration check before the engine has had time to cool

down. Table 11 limits are applicable to fuel system Configurations A and B fuel controls

only. The minimum allowable time for Configuration C is two seconds. (Refer to Fuel

System, Section 1.)

(1) Turn the generator switch off.

CAUTION: DURING RAPID THROTTLE MOVEMENTS, MAKE APPROPRIATE

ANTI-TORQUE PEDAL CORRECTIONS TO PREVENT THE AIRCRAFT FROM

TURNING ON LOOSE OR SLICK SURFACES.

(2) Rotate the twist grip to full open, hold collective at flat pitch and stabilize N₂ at exactly 100%

(103% for model H500 helicopters) for approximately 15 seconds (beep as required).

TABLE 11

Minimum Allowable Deceleration Time (Seconds)

for Fuel System Configurations A and B

Temperature (OAT)

Sea

4,000 Feet

6,000 Feet

12,000 Feet

°F

°C

Level

(1219 Meters)

(1829 Meters)

(3658 Meters)

-18

2.0

2.5

2.0

2.1

2.2

2.8

2.4

2.5

2.6

3.2

NOTE: Provided that the deceleration time check shows satisfactory operation when made at

80°F (27°C) OAT or below, no check is required above 80°F (27°C). Deceleration time

limits extrapolated from Table 11 for OAT’s above 80°F (27°C) are not valid.

(3) Snap the twist grip to the IDLE position. Simultaneously start a time count using a stop watch

or watch with a sweep second hand. Stop the time as the N₁ needle passes through 65%.

The minimum deceleration time for Configurations A and B shall be in accordance with Table

11. The minimum allowable deceleration time for Configuration C is two seconds.

NOTE: Practice and/or retakes may be required before proficiency is obtained in timing the

deceleration.

Page 106

(a) On single engine applications, if multiple controls are installed, make separate decel

checks using the pilot and copilot twist grips.

(b) On multi-engine applications, make a deceleration check of each engine. Make separate

decel checks using the pilot and the copilot twist grips.

(4) If deceleration time is less than the limits of Table 11 (Configuration A or B) or two seconds

(Configuration C), make two more checks to confirm the time. If the confirmed time is less

than the minimum allowable time, proceed to the rigging check.

(5) If N₁ speed drops below 59%, or if a flame out is experienced during the deceleration check,

proceed to the rigging check before making a second attempt.

51.

Fuel Control Rigging Check

A. Check the rigging of the gas producer fuel control after a deceleration check has revealed the

deceleration time to be less than the allowable limits given in Table 11. This check is also required

after installation of a fuel control or any component of the rigging system. Make the rigging check

with the engine shut down using the following procedure:

CAUTION: DO NOT ADJUST THE MINIMUM STOP TO COMPENSATE FOR AIRCRAFT RIGGING

DIFFICULTIES. THE MINIMUM STOP IS SET ON A FLOW BENCH AND IS NOT A

FIELD ADJUSTMENT.

(1) Check to ensure that sufficient travel is provided to allow physical contact with the gas

producer minimum stop at or before the full closed position of the twist grip.

(2) Check the travel to the opposite end. Physical contact must be made with the gas producer

maximum stop at or before the full open position of the twist grip.

(3) Looseness encountered in the rigging must be minimized by replacement of worn items and/or

accuracy of the rigging. Looseness that cannot be removed must be within the limits indicated

in FIG. 19. Check the looseness as follows:

(a) Start with the twist grip at the full open position then rotate the grip to the IDLE position.

The pointer must be at the 30 degree mark.

(b) Start with the twist grip at the full closed position then rotate the grip to the IDLE position.

The pointer must be no more than 5/64 in. (2.0 mm) below the 30 degree mark.

NOTE: Make rigging adjustments on aircraft having dual controls using the pilots twist

grip. Recheck the linkage movement using the copilots twist grip. The limits of

FIG. 19 are applicable to both sets of controls.

(4) Repeat the deceleration check. If the deceleration time is less than the allowable minimum

proceed with the idle speed check.

Page 107

Fuel Control Quadrant and Pointer

FIG. 19

52.

Engine Idle Speed Setting

A. Check the idle speed setting with the engine running. Stabilized idle speed should repeat every

time, whether the twist grip is slowly rolled or snapped to the IDLE position. Failure of the stabilized

speed to repeat is cause for a recheck of the rigging. Check for proper idle adjustment rigging as

follows:

(1) Roll the twist grip to IDLE and let N₁ stabilize. Mark (pencil) the precise position of the pointer

tip on the fuel control quadrant.

(2) Release the idle detent on the twist grip. Very slowly roll the twist grip in the direction of cutoff

just enough to obtain perceptible movement of the pointer tip (approximately the width of the

pencil mark). If N₁ idle speed decreases take the following corrective action:

(a) If the pointer is at or above the 30 degree mark, rerig the aircraft linkage to move the

pointer tip to a point just below the 30 degree mark.

(b)

(If the pointer is more than 5/64 in. (2.0 mm) below the 30 degree mark, rerig the aircraft

linkage to move the pointer closer to the 30 degree mark.

(3) If N₁ idle speed did not change when the twist grip was rolled toward cutoff, very slowly roll the

twist grip in the direction of increased power. Obtain perceptible movement of the pointer tip.

No increase in N₁ speed is permitted before the fuel control pointer indicates 30 degrees. An

increase in speed before the pointer reaches 30 degrees indicates the fuel control internal

rigging is incorrect.

(Refer to Rolls-Royce Commercial Engine Bulletin 250 CEB-27 for

corrective action.) An increase at or above the 30 degree mark is normal.

Page 108

(4) When the rigging is correct, change the idle speed adjustment screw to obtain a 59-65% N₁

speed setting with the generator switch off. (Ref. FIG. 19) Using 6798292 wrench, turn the

screw clockwise to increase or counter-clockwise to decrease N₁ speed. A 1/8 turn

adjustment changes engine speed approximately 5%. If N₁ speed does not respond to the idle

speed screw adjustment, the rigging is establishing idle speed. Rerig as required. If N₁ speed

does respond to the idle speed screw, make the 59-65% N₁ setting.

(5) Repeat the deceleration check. If deceleration time is less than the allowable minimum, clean

the control inlet P_c filter, the P_x and P_y bleeds.

53.

Fuel Control Fuel Cutoff Valve Operational Check

A. To ensure that the cutoff valve is functioning properly, proceed as follows:

(1) Deactivate the ignition system.

WARNING: BE AWARE OF THE POTENTIAL FIRE HAZARD OF FUEL IN AN OPEN

CONTAINER.

(2) Disconnect the fuel supply hose from the fuel nozzle and place the hose in a clean container.

(3) Close the throttle until it is seated firmly on the minimum throttle stop.

(4) Motor the engine for approximately 15 seconds. There should be no fuel coming from the fuel

supply hose. If fuel continues to flow during the motoring operation, the fuel control must be

replaced.

(5) Reconnect the fuel supply hose to the fuel nozzle. Torque coupling nut to 80-120 lb in.

(9.0-14.7 N^.m).

(6) Reactivate the ignition system.

54.

Throttle Torque Check

A. Higher than normal throttle torque can occur due to binding of the governor shaft in the governor

shaft bushing. This binding can be the result of corrosion build-up on the governor shaft assembly,

causing an interference fit in the governor shaft bushing.

(1) Rotate the throttle and check for higher than normal torque.

(2) If higher than normal torque exists, apply lubricant, standard engine oil MIL-PRF-23699

(NATO Code 0-156), to the area shown in FIG. 20.

(3) Rotate the throttle following lubricant application to assure penetration.

(4) Repeat the spray application if necessary.

55.

Gas Producer Fuel Control Air Circuit Cleaning

A. Clean the P_c filter and P_x and P_y bleeds on fuel controls which still have too rapid deceleration after

a rigging check and an idle adjustment have been made. Replace Configuration A and B controls

which have too rapid deceleration after cleaning.

B. Clean the control inlet P_c filter and the P_x and P_y bleeds on fuel controls of fuel control system

configuration C. (Refer to Fuel System, Section 1.) Remove, clean, and reinstall the P_c filter and

the P_x and P_y bleeds as follows:

(1) Remove the fuel control from the engine. Immediately cap all open ports.

CAUTION: KEEP THE WORK AREA CLEAN AT ALL TIMES TO ENSURE THAT

CONTAMINANTS DO NOT GET INTO THE FUEL CONTROL.

(2) Clean the P_c filter area of the fuel control with methylethylketone. Blow dry.

(3) Remove the P_c filter. (Ref. FIG. 21) Carefully remove the three O-rings from the filter. These

O-rings are reusable if undamaged.

Page 109

CAUTION: USE NORMAL PRECAUTIONS WHEN WORKING WITH SULFURIC ACID.

CLEANING TIME OF THE FILTER WHEN USING SULFURIC ACID OF 1.175

SPECIFIC GRAVITY SHOULD NOT EXCEED 30 MINUTES.

(4) Agitate the P_c filter in a solution of sulfuric acid or electrolyte that has a specific gravity of

approximately 1.175. After removal from the cleaning solution, thoroughly rinse the filter in

water to neutralize the acid.

NOTE: Mineral spirits may be used if sulfuric acid is not available.

(5) Suction clean the P_c filter chamber in the fuel control. (Ref. FIG. 22)

CAUTION: TO AVOID INTERMIXING THE P_X AND P_Y BLEEDS, DO NOT REMOVE BOTH

BLEEDS AT THE SAME TIME. THE P_X AND P_Y BLEEDS ARE NOT

INTERCHANGEABLE.

(6) Remove, clean, and reinstall the P_x bleed; then, remove, clean, and reinstall the P_y bleed.

Use Bendix T26927 wrench (early configuration controls) or Bendix 2550678 (late

configuration controls) for removing or installing the bleeds.

(Ref. FIG. 1.)

(7) Clean the P_x or P_y bleed ultrasonically if equipment is available; if it is not, hold the bleed with

instrument tweezers and agitate it in mineral spirits in a clean container. Insert a sewing

thread through the bleed hole. Slide the bleed back and forth on the thread to remove the film.

Gas Producer Fuel Control P_x and P_y Bleed Removal

FIG. 22

CAUTION: DO NOT BLOW THE BLEED DRY. THE SMALL BLEED CAN BE EASILY LOST

OR DAMAGED.

CAUTION: DO NOT USE A PROBE TO REMOVE PARTICLES LODGED IN THE BLEED.

(8) Inspect the P_x or P_y bleed for cleanliness using a flashlight. Place the bleed on the center of

the lens so the light can be seen through the bleed hole. Reclean the bleed if any particles or

coating can be seen.

(9) Install the cleaned P_x or P_y bleed in the fuel control using wrench, Bendix No. T26927. Torque

to 9-11 lb in. (1.02-1.13 N^.m).

Page 111

(10) Install the P_c filter in the fuel control. If new O-rings are required use Bendix P/N 953515-4,

951394, and 951395. Sparingly lubricate all O-rings with ASTM No. 5 (or equivalent). Torque

the fitting to 40-50 lb in. (4.5-5.6 N^.m).

(11)

Make a record of cleaning the P_c filter and the P_x and P_y bleeds in the Engine Log book.

(12) Install the fuel control on the engine.

(13) Repeat the deceleration check. If deceleration time is less than the allowable minimum,

replace the fuel control.

(14) Perform an acceleration check.

WARNING: DURING THE ACCELERATION CHECK, THE AIRCRAFT MAY REACT OR

BECOME LIGHT ON ITS SKIDS. DO NOT SNAP THE TWIST GRIP TO THE

FULL THROTTLE POSITION.

WARNING: DO NOT EXCEED TORQUE, TEMPERATURE, OR N₁ SPEED LIMITS

DURING THE ACCELERATION CHECK.

(a) Make a normal engine start. Allow the engine to operate at IDLE (59-65% N₁) until the

indicators stabilize.

(b) With the generator switch OFF and the collective pitch control at its minimum position, roll

the twist grip toward full throttle, then back off to IDLE. The twist grip motion need be

only quick enough to require the engine to demonstrate normal acceleration capability.

(d) If acceleration is too slow, replace the fuel control.

(e) If acceleration rates are inconsistent, check the rigging using the aircraft manual. Repeat

the acceleration check.

(f)

If acceleration rate is consistent, no further action is required.

56.

Checking the Fuel Control Max Speed Stop

The max speed stop setting can be checked during ground operation of the engine by first installing

a fixture (spacer) between the throttle lever stop and the max. speed stop screw. This spacer (Fuel

Control Max. Stop Screw Setting Fixture 6872482) is sized to stop the throttle lever at 84% N₁

speed which is 20% below the 104% max. continuous limit of the engine. Make the max. speed

stop setting as follows:

(1) Attach a warning note to the pilot’s control stick. This note shall read:

WARNING--MAINTENANCE TOOL

INSTALLED ON THE FUEL CONTROL

(2) Make a match mark across the serrations of the fuel control throttle lever and arm for a

reference in case the relative index is disturbed during the check.

(3) Remove the throttle lever retaining nut. Do not remove the throttle lever.

CAUTION: OVERTORQUEING THE NUT CAN CAUSE BINDING OF THE THROTTLE SHAFT.

(4) Place the Fuel Control Max. Stop Screw Setting Fixture 6872482 (20% N₁ Spacer Tool) on the

lever shaft as shown in FIG. 23. Reinstall nut. Torque to 40-50 lb in. (4.5-5.6 N^.m).

(5) Check for max. N₁ rpm with the tool installed as follows:

WARNING: THE HELICOPTER MAY LIFT OFF DURING THIS CHECK IF IT IS NOT

SUFFICIENTLY LOADED.

(a) Start engine and stabilize at Idle.

(b) Advance the throttle as far as it will go. Adjust Beep to maximum position.

N1.

Page 112

(d) Make a normal engine shutdown.

Adjust the max. speed stop screw as follows, if required.

NOTE: It is the responsibility of the operator to assure the accuracy of the TOT and N₁

indicating systems prior to adjusting the max. speed stop screw.

Gas Producer Fuel Control with 20% N₁ Fixture Installed

FIG. 23

a Add 20% to the N₁ reading to account for fixture 6872482. The total should be

104%.

EXAMPLE:

82.4%

N₁ indicator reading

+20.0

tool allowance

102.4%

N₁ max. setting

b If the N₁ max setting is above 104%, make no adjustment. If the setting is less

than 104%, as in example, turn the max. speed stop screw clockwise into the

casting to increase N₁ speed. It is recommended that the screw be turned in

increments of one turn maximum before the setting is rechecked. Repeat the

setting until 104% is attained. One turn equals approximately 1% speed.

Remove fixture 6872482 and reinstall the throttle lever nut. Torque nut to 40-50 lb

in. (4.5-5.6 N^.m). Be sure throttle lever match mark is still aligned.

Check that the throttle lever stop contacts the max. speed stop screw.

Remove warning note from pilot’s control stick.

NOTE: This concludes the ground adjustment of the max speed stop screw.

However, if the allowable limit of at least one of the three main indicators

(torque, temperature, or N₁ speed) cannot be reached in flight, readjust the

max. speed stop screw. Do not exceed existing torque, temperature, or N₁

limits.

Page 113

57. Power Turbine Fuel Governor Removal

NOTE: Replace the power turbine fuel governor if it is found to be the cause of engine malfunction.

(Ref. FIG. 24)

CAUTION: WHEN THE POWER TURBINE FUEL GOVERNOR IS BEING REMOVED USE

EXTREME CARE TO PREVENT FOREIGN MATERIALS FROM ENTERING THE

PNEUMATIC LINES OR GOVERNOR PORTS.

A. Remove the power turbine fuel governor from the engine as follows: (Ref. FIG. 8, 9, or 10)

(1) Disconnect lines and linkage.

(2) Remove three nuts and washers which secure the governor to the power and accessories

gearbox housing.

1. Power Turbine Governor Lever

2. Governing Pressure (Pg

3. Sensing Pressure Tee-filter (P_c)

4. Regulated Air Pressure (P_r)

5. Governor Servo Pressure (P^y)

Power Turbine Fuel Governor

FIG. 24

(3) Remove the governor assembly.

CAUTION: WHEN REMOVING FITTINGS, BE CAREFUL NOT TO CAUSE A LOAD ON THE

GOVERNOR DRIVE SHAFT. USE THE WOODEN PROTECTIVE SHIPPING

BLOCK TO PROTECT THE SHAFT FROM THE WORK BENCH.

(4) If the unit is to be replaced, remove all fittings necessary for installation of the replacement

unit.

NOTE: In installations where the power turbine governor lever is not required, remove the

lever from the replacement governor and install it on the governor being returned for

overhaul.

Page 114

58. Bendix Governor Pg Air Circuits Maintenance and Cleaning

A. A contaminated P_g air circuit in the power turbine governor may cause droop, overshoot or hunting

of the N₂ rotor. Correct this contamination condition by cleaning the governor P_g orifice and P_g

bleed. (Ref. FIG. 25) The orifice and bleed can be cleaned with the governor either installed or

removed from the engine. Clean as follows.

Bendix Governor Pg Bleed and Pg Orifice

FIG. 25

(1) Carefully clean the exterior of the governor using methylethylketone. Be sure all contamination

is removed in the areas of the P_g outlet and the Pg orifice. Blow dry.

(2) If the governor is not removed from the engine, remove the governor-to-accumulator (or

double check valve) P_g line. Inspect the P_g line for obstructions.

(3) Remove the reducer from the P_g outlet port. Carefully remove the O-ring from the fitting; the

O-ring can be reused if undamaged. If the O-ring must be replaced, use P/N 6843332-05 (or

alternate MS9387-05).

(4) Remove the P_g bleed using Bendix 2550678 screwdriver (or a commercial screwdriver with

3/16 in. (4.76 mm) flat tip.

(5) Remove lockwire from the P_g orifice. Remove orifice using a 1/8 in. (3 mm) hex wrench. Use

caution during removal to avoid losing the shims or damaging the O-ring. The O-ring can be

reused if undamaged. If the O-ring must be replaced, use Bendix 953508-8.

(6) Clean the bleed and the orifice in the same manner. Clean as follows:

CAUTION: EXERCISE CAUTION NOT TO LOSE THE BLEED OR THE ORIFICE IF AIR

PRESSURE IS USED FOR DRYING.

(a) Use an ultrasonic cleaner if available; if it is not, agitate the part in perchlorethylene or

mineral spirits in a clean container. Insert a sewing thread through the passage of the

bleed or orifice (pre-screened orifices only); slide the part back and forth on the thread to

remove all traces of foreign matter. Air dry the part.

Page 115

(b) Inspect the part for cleanliness. Inspect by placing the part in the center of a flashlight

lens and sighting through the passage. No particles or coating of any kind should be

seen. Repeat sub para (a) and (b) if the part is not completely clean.

(7)

Clean the surface of the P_g flapper valve that mates with the P_g orifice. Access to the flapper

valve is through the hole in the governor body that retains the P_g orifice. Use a cotton swab

with a highly volatile residue-free solvent (perchlorothene or equivalent) applied to the tip.

(8)

Inspect the valve surface for cleanliness using a flashlight. Reclean the surface if any particles

or coating can be seen.

(9)

Reinstall the P_g bleed using Bendix 2550678 screwdriver (or a commercial screwdriver with a

3/16 in. (4.76 mm) flat tip. Screw the bleed in until it is tight, then back out two turns.

Retighten bleed to 9-11 lb in. (1.02-1.24 N^.m).

(10) Lightly lubricate the O-ring. Install O-ring and reducer in the P_g outlet port. Torque reducer to

75-110 lb in. (8.47-12.43 N^.m).

(11)

If the cleaning was accomplished with the governor on the engine, install the

governor-to-accumulator (or double check valve) P_g line. Torque coupling nuts to 80-120 lb

in. (9.04-13.56 N^.m).

(12) Lightly lubricate the O-ring. Install the P_g orifice with O-ring and shims. Be sure that all of the

shims that were removed are reinstalled with the orifice. Tighten orifice finger tight. Be sure

the shims are properly positioned before final tightening the orifice.

(13) Torque the orifice to 14-15 lb in. (1.58-1.69 N^.m) using a 1/8 in. (3 mm) hex wrench. This

torque value is critical and must be strictly observed. Secure the orifice with lockwire.

(14) Visually inspect the governor to ensure that all lines, lockwire, etc have been reinstalled. Start

the engine. Allow five minutes for warm-up before checking operation of the governor.

Replace the governor if N₂ continues to droop, overshoot or hunt.

Install the power turbine fuel governor on the engine as follows:

NOTE: Depending on the configuration status of the governor, certain fittings may be included as

part of the governor assembly. Determine which fittings are a part of the replacement

governor before removing any fittings from the replaced governor.

NOTE: In installations where the power turbine governor lever is not required, remove the lever

from the replacement governor and install it on the governor being returned for overhaul.

(1) Coat drive shaft with Lubriplate 130A (or equivalent). Use the wooden protective shipping

block to protect the shaft from the work bench when installing the fittings.

CAUTION: BE CERTAIN THAT THE GOVERNOR DRIVE PILOT IS PROPERLY INSERTED IN

THE GEARBOX.

WARNING: FAILURE TO PROPERLY INSTALL, ALIGN, AND TORQUE FUEL, OIL, AIR

FITTINGS AND TUBES COULD RESULT IN AN ENGINE FAILURE.

(2) Install in reverse order of removal.

(3) Torque mount pad nuts to 70-85 lb in. (7.9-9.6 N^.m). Torque control air line coupling nuts to

80-120 lb in. (9.0-13.6 N^.m).

NOTE: Be sure the procedures and precautions of Rigid Tube Installation are observed

when installing fuel system tubes.

CAUTION: OVERTORQUING CAUSES BINDING OF THE LEVER SHAFT.

(4) If the power turbine governor lever requires repositioning, loosen the nut, reposition then

Torque the nut to 40-50 lb in. (4.5-5.6 N^.m).

(5) Perform a Fuel System Pneumatic Leak Check.

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(6) Check run the engine after governor replacement. (Refer to Engine Check Run.)

(7) Make appropriate entry relative to governor replacement in the Engine Log.

59. Throttle Torque Check

A. Higher than normal throttle torque can occur due to binding of the throttle shaft in the throttle shaft

bushing This binding can be the result of corrosion build-up on the throttle shaft assembly, causing

an interference fit in the throttle shaft bushing.

(1) Rotate the throttle and check for higher than normal torque.

(2) If higher than normal torque exist, apply lubricant, standard engine oil MIL-PRF-23699 (NATO

Code 0-156), to the areas shown in FIG. 26.

(3) Rotate the throttle following lubricant application to assure penetration.

(4) Repeat the spray application if necessary.

Lubricating Bendix/Allied Signal Fuel Control Throttle Shaft and Bushing

FIG. 26

60. Fuel Pump and Filter Assembly Maintenance

Replace the complete pump assembly if it is found to be the cause of engine malfunction. (Ref. FIG. 27

or 28)

NOTE: The unit exchange fuel pump package can be either a dual element set or a single element

set. Since the plumbing for the two pumps differs, exchange the two pump-to-control tubes

with the pump. Also, remove the two 1/2-20 unions and keep them for installation in the

replacement pump.

A. Remove the fuel pump and filter assembly from the engine as follows:

(1) Remove the fuel inlet and outlet lines, control bypass lines, and the fuel pump and filter

assembly seal drain line at the fuel pump.

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(2) Remove the three self-locking nuts and washers which secure the fuel pump to the power and

accessories gearbox housing. Remove pump from mounting studs.

(3) Remove the mounting flange gasket. Discard packing.

(4) Remove the two unions and bushing from the pump and keep them for installation in the

replacement pump. Discard packings.

B. Install the fuel pump and filter assembly on the engine as follows:

CAUTION: IF THE REPLACEMENT PUMP IS NOT THE SAME TYPE OF PUMP (SINGLE

ELEMENT VS DUAL ELEMENT) AS THE PUMP BEING REPLACED, THE PORT

LOCATIONS WILL BE DIFFERENT. CHECK THE APPROPRIATE ILLUSTRATION

(FIG. 27 or 28) BEFORE INSTALLING THE FITTINGS. ALSO, THE TUBING

CONFIGURATION DIFFERS FOR THE TWO PUMPS. DO NOT ATTEMPT TO

REINSTALL THE EXISTING FUEL TUBES IF THE TYPE OF PUMP HAS CHANGED.

(1) Lubricate three packings and install one each with the unions in the control bypass return port

and one with the union in the pump discharge return port. Torque the union to 75-110 lb in.

(8.5-12.4 N^.m). Install the bushing into the fuel pump inlet port. Torque the bushing to

150-200 lb in. (17-23 N^.m).

(2) Install a new fuel pump drive packing seal.

(3) Install gasket on mounting pad.

(4) Coat pump drive splines and packing with engine oil. Coat the fuel fitting with MIL-L-6081 oil

(Atlantic Refining Co. 31100, or equivalent). Coat the studs with antiseize compound.

(5) Install pump on mounting studs. Install three washers and self-locking nuts.

CAUTION: FAILURE TO PROPERLY INSTALL, ALIGN, AND TORQUE FUEL, OIL, AIR

FITTINGS AND TUBES COULD RESULT IN AN ENGINE FAILURE.

(6) Torque mount pad nuts to 70-85 lb in. (7.9-9.6 N^.m). Torque fuel line coupling nuts to

150-200 lb in. (17-23 N^.m).

(7) Be sure the procedures and precautions of Rigid Tube Installation are observed when installing

fuel system tubes.

(8) Install the fuel control-to-pump bypass (P_o) fuel tube. Torque coupling nuts to 150-200 lb in.

(17-23 N^.m).

(9) Install the pump-to-fuel control inlet fuel (P₁) tube. Torque coupling nuts to 150-200 lb in.

(17-23 N^.m). Clamp fuel control P₁ and P_o tubes together. Torque clamp nut to 35-40 lb in.

(3.9-4.5 N^.m).

(10) Purge air from the fuel system. (Refer to Fuel System Air Purging for details.)

(11) Check run the engine after fuel pump replacement. (Refer to Engine Check Run.)

(12) Make appropriate entry relative to pump replacement in the Engine Log.

NOTE: After the fuel pump has been replaced, if a false start or a start that is not completed

in a total time of one minute is encountered, return the gas producer lever to FUEL

OFF and motor the engine without ignition for 10 seconds.

61.

Fuel Pump Filter Bypass Valve Operational Check

A. The fuel pump incorporates a filter bypass valve which allows fuel to bypass the pump filter element

if it becomes clogged. An open valve allows unfiltered fuel to be supplied to the fuel control. Make

the filter bypass valve operational check whenever any of the following conditions exist:

CAUTION: IF FUEL SYSTEM CONTAMINATION IS KNOWN OR SUSPECTED, REFER TO FUEL

FILTER BYPASSED IN THE SPECIAL INSPECTIONS TABLE 9, ITEMS 14AF, AG, AND

AK.

(1) The impending filter bypass warning light comes on (this feature is not on all aircraft).

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(2) There is an indication the fuel pump filter bypass valve has been bypassing. Bypassing is

evidenced by contamination in the fuel control or fuel control inlet filter.

(3) When the fuel pump filter is replaced. Replacement of the element is required when the

impending filter bypass warning system has been activated or during the scheduled 300 hour

inspection. Under no circumstance should the element be cleaned and reused or remain in

service beyond the 300 hour limit.

62.

Operational Checks

Check the fuel pump bypass valve to ensure that the valve is not stuck in bypass; the valve will

bypass if the filter becomes clogged and the valve will return from bypass to the closed position.

Determine that the bypass valve is not stuck in the open (bypass) position as follows:

(1) Remove lockwire and the filter cover. Separate the element from the pump. Discard two

O-rings. (Ref. FIG.s 6 and 7)

(2) Install a caplug in the filter housing. Use NAS 813-14 caplug for single element pumps and

NAS 813-8 caplug for dual element pumps. (Ref. FIG. 29)

(3) Remove the line (or plug) from the after filter (AF) pressure drop port. (Ref. FIG. 27 or 28)

(4) Install an AN 815-3 fitting in the AF port. Install a length of Tygon tube on the AN 815-3

fitting.

(5) Using a funnel, fill the Tygon tube with fuel.

(Ref. FIG. 29) Observe the filter housing area for

leakage.

(a) Observed Fuel Leakage. Leakage exceeding 10 drops per minute is excessive and

indicates the valve is open (bypass position) and contaminated fuel has entered the fuel

control system.

Clean and inspect the fuel control inlet filter in accordance with the applicable part of

Gas Producer Fuel Control Air Circuit Cleaning.

Remove and inspect the fuel nozzle. (Refer to Fuel Nozzle Maintenance.) Also, the

nozzle inlet screen must be checked for contamination and the spray pattern must

be checked for lack of streaking. This service is available at each Distributor Facility.

(b) No Observed Fuel Leakage. No leakage is an indication that the bypass valve has

satisfactorily closed (non-bypass position). Proceed with the check to ensure that the

valve will open during clogged filter conditions.

Determine that the bypass valve will open (bypass) if the filter becomes clogged as follows:

(1) With the caplug still in place in the filter housing, reinstall the filter bowl cover assembly.

WARNING: AVOID FUEL ACCUMULATION IN THE ENGINE COMPARTMENT BY PROVIDING

A SUITABLE CONTAINER TO COLLECT FUEL DISCHARGED FROM THE

TYGON TUBE ATTACHED TO THE AF PRESSURE PORT.

(2) Momentarily actuate the aircraft fuel boost (start) pump. If the aircraft is equipped with a

differential pressure light, the light should come on, indicating bypass due to clogging.

(3) Check the fuel flow from the AF pressure tap.

(a) No fuel flow is an indication the bypass valve is stuck closed. Return pump to an

Overhaul facility for repair.

(b) Fuel flow from the AF pressure tap indicates the bypass valve has satisfactorily opened.

Proceed with the check to ensure that the valve will return to the closed (non-bypass)

position.

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Remove the filter bowl cover assembly. Leave the caplug in place.

Using a funnel, fill the Tygon tube with fuel. (Ref. FIG. 29) Observe the filter

housing area for fuel leaks.

a Observed Fuel Leakage. Leakage in excess of 10 drops per minute is

excessive and indicates the bypass valve is open (bypass position). Return the

fuel pump to an Overhaul Facility for repair of this condition.

b No Observed Fuel Leakage. No leakage is an indication that the bypass valve

has satisfactorily closed (non-bypass position).

(d) After the operational checks have been completed, return acceptable fuel pumps to

service.

Remove the caplug, the AN 815-3 fitting and the Tygon tube.

Reinstall the filter element and the filter bowl cover with O-rings. Install the

differential pressure sensing line or plug, as required.

Purge air from the filter bowl area of the single element pump. (Refer to from the

Fuel System Air Purging.)

63.

Double Check Valve Maintenance

A. Replace the double check valve as follows:

CAUTION: WHEN THE DOUBLE CHECK VALVE IS REMOVED USE EXTREME CARE TO

PREVENT FOREIGN MATERIALS FROM ENTERING THE PNEUMATIC LINES OR

THE DOUBLE CHECK VALVE.

(1) Remove the hose assembly from the union at the 90° elbow.

(2) Remove the union-elbow assembly from the double check valve. Discard O-ring.

(3) Remove the clamp retaining the double check valve to the firewall shield.

(4) Remove the double check valve from the accumulator. Discard the O-ring.

CAUTION: DO NOT TORQUE THROUGH THE DOUBLE CHECK VALVE AT ANY TIME. USE

A WRENCH ON ONLY THE VALVE COMPONENT THAT IS BEING TIGHTENED

OR LOOSENED.

(5) Install the replacement double check valve with new O-ring in the accumulator. Torque valve

to 40-65 lb in. (4.5-7.3 N^.m).

(6) Install the union-elbow assembly with new O-ring in the double check valve. Torque to 55-80

lb in. (6.2-9.0 N^.m).

(7) Install the clamp on the double check valve. Attach clamp to firewall shield using a bolt,

spacer, washer, and nut. Torque clamping nut to 35-40 lb in. (3.9-4.5 N^.m).

WARNING: FAILURE TO PROPERLY INSTALL, ALIGN, AND TORQUE FUEL, OIL, AIR

FITTINGS AND TUBES COULD RESULT IN AN ENGINE FAILURE.

(8) Attach the hose assembly to the union at the 90° elbow. Torque nut to 80-120 lb in. (9.0-13.6

N^.m).

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64.

Accumulator Maintenance

NOTE: Clean and test the accumulator any time it is removed from the engine.

Remove, the accumulator as follows: (Ref. FIG. 30 and 31)

(1) Remove the accumulator-to-fuel control and the check valve-to-governor tubes (or hose).

Do not apply torque through the accumulator or check valve at any time; use adjacent

hexagonal surfaces.

(2) Remove clamp retaining bolts and separate the accumulator-check valve assembly from the

engine.

(3) Remove the double check valve from the accumulator. Discard O-ring.

(4) Remove the elbow from the accumulator. Discard O-ring.

(5) Remove clamp from the accumulator.

Clean the accumulator as follows:

(1) Immerse the accumulator in mineral spirits; agitate until clean.

(2) Blow accumulator completely dry using filtered dry air.

Test the accumulator as follows:

(1) Pressurize the accumulator using 35 psig (241 kPa) air pressure. Replace or return the

accumulator to the distributor for repair if leakage is detected.

Assemble the accumulator as follows:

(1) Install elbow with lubricated O-ring in the accumulator. Torque jam nut to 55-80 lb in. (6.2-9.0

N^.m).

(2) Place clamp on the accumulator.

(3) Lubricate O-ring and assemble with the double check valve onto the accumulator. Torque

valve to 40-65 lb in. (4.5-7.3 N^.m). Do not apply torque through the accumulator.

Install the accumulator as follows:

(1) Secure the retaining clamp(s) to the firewall shield. Torque clamp nut to 35-40 lb in. (3.9-4.5

N^.m).

(2) Install the accumulator-to-fuel control tube and the check valve to governor hose (this is a

tube if the check valve is a poppet type). Torque coupling nuts to 80-120 lb in. (9.0-13.6 N^.m).

Page 125

65.

Lubrication System

WARNING: MAINTAIN THE COMPLETE OIL SYSTEM IN ACCORDANCE WITH ENGINE AND

AIRCRAFT INSTRUCTIONS. FAILURE TO MAINTAIN THE OIL SYSTEM CAN

RESULT IN SUDDEN ENGINE STOPPAGE.

WARNING: OPERATORS MUST MAINTAIN THE ENGINE MAGNETIC DRAIN PLUGS AND

INDICATING SYSTEM IN OPERATING ORDER AND COMPLY WITH AIRCRAFT

FLIGHT MANUAL AND ENGINE OPERATION AND MAINTENANCE MANUAL

INSTRUCTIONS WHEN AN RECEIVED. NEVER ALLOW AN ACCEPTABLE

SPECTROGRAPHIC OIL ANALYSIS PROGRAM (SOAP) READING TO OVERRIDE

MAGNETIC DRAIN PLUG INDICATIONS. INDICATION IS

WARNING: FAILURE TO PROPERLY INSTALL, ALIGN AND TORQUE FUEL, OIL, AND AIR

FITTINGS AND TUBES COULD RESULT IN AN ENGINE FAILURE.

A. Lubrication system maintenance includes: cleaning and inspecting the magnetic drain plugs;

changing the system oil; cleaning the oil filter; replacing the lube oil filter housing assembly;

adjusting the pressure regulating valve; cleaning and inspecting the turbine pressure oil system

check valve; replacing gas producer support pressure oil tube; flushing the gas producer support oil

supply passage; inspecting and cleaning the power turbine support scavenge oil strut; cleaning

power turbine support pressure oil tube; oil flow measurement; and cleaning power turbine labyrinth

seals.

B. Do not use silicone lubricants except where specified. Use only the lubricants recommended in the

engine publications.

C. The gas producer turbine support pressure oil tube should normally not be removed. If this tube

must be removed, flush the tube passage in the support before tube installation. (Refer to Gas

Producer Turbine Support Pressure Oil Passage Flushing.)

66.

Oil Temperature Limit Exceeded

The maintenance actions required when oil temperature limits have been exceeded are governed

by the overtemperature conditions encountered. Specific conditions and the respective

maintenance action requirements are as follows:

(1) Engine oil temperature exceeds 107°C (225°F) but remains less than 120°C (248°F) for a

period not exceeding ten minutes. Oil pressure remains normal.

(a) Check for carbon deposits (coking). (Refer to Carbon Buildup Inspection.)

(b) Inspect and clean or replace the oil filter.

(Use 6798860 puller to remove filter cap.)

(d) Reservice the oil system with new oil. Ground run the engine for 10 minutes, obtain as

high a power setting as possible without lift-off (without exceeding Max. Continuous

rating).

(e) Reinspect the oil filter and the magnetic drain plugs. If no carbon particles can be found,

return the engine to service. If carbon particles are found, repeat the maintenance

procedure.

(f)

Reinspect the oil filter and the magnetic drain plugs after five hours of engine operation.

If carbon particles are found, repeat the maintenance procedure.

(2) Engine oil temperature exceeds 107°C (225°F) but remains less than 120°C (248°F) for a

period not exceeding 10 minutes. Oil pressure abnormal.

(a) Overtemperature may adversely affect oil pressure regulation. Replace the oil filter

housing assembly. (Refer to Lube Oil Filter Housing Replacement.) If normal oil pressure

and oil pressure regulation is restored by replacement of the housing assembly, send the

removed housing assembly to an authorized facility for repair, noting the reason for

removal.

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(b) Check for carbon deposits (coking). (Refer to Carbon Buildup Inspection.)

(Use 6798860 puller to remove filter cap.)

(d) Inspect and clean the magnetic drain plugs.

(e) Reservice the oil system with new oil. Ground run the engine for 10 minutes, obtain as

high a power setting as possible without lift-off (without exceeding Max. Continuous

rating). Adjust engine oil pressure as required.

(f)

Reinspect the oil filter and the magnetic drain plugs. If no carbon particles can be found,

return the engine to service. If carbon particles are found, repeat the maintenance

procedure.

(g) Reinspect the oil filter and the magnetic drain plugs after five hours of engine operation.

If carbon particles are found, repeat the maintenance procedure.

(3) Oil temperature exceeds 120°C (248°F) momentarily or 107°C (225°F) for a period exceeding

10 minutes.

(a) Remove the engine and send it to an overhaul facility for inspection or repair as required.

(b) Tag the engine indicating that max allowable operating oil temperatures were exceeded.

Give maximum temperature and elapsed time.

67.

Low Oil Pressure Operation

If deterioration in engine oil pressure is experienced, the following sequence of checks is

suggested.

(1) Check the quantity of oil in the tank to be sure it is adequate.

(2) Remove, inspect, clean and reinstall the magnetic plugs and filter. (Use 6798860 puller to

remove filter cap.)

(3) Confirm the pressure discrepancy using a direct reading gage.

CAUTION: DO NOT MAKE A PRESSURE REGULATING VALVE ADJUSTMENT TO

CORRECT FOR A RAPID CHANGE IN OIL PRESSURE. THESE CONDITIONS

ARE CAUSE TO SUSPECT OTHER OIL SYSTEM PROBLEMS HAVE

DEVELOPED.

(4)

Increase the pressure adjustment if necessary. Check the gage for change in pressure. If no

change in pressure is evident as a result of the adjustment, continue with the sequence of

checks to isolate and correct the fault.

(5)

Remove and check the bottom magnetic drain plug. Drain oil from the gearbox. Do not install

the magnetic drain plug, after residual oil has drained, until a check for internal oil leakage has

been made.

NOTE: Leakage from the bottom drain port is an indication that the oil tube O-ring and/or oil

pump may be leaking. Leakage will also be evident if the check valve is not properly

seated.

(6)

If bottom drain port leakage is evident, remove the oil filter housing and fill the pump

pressure-out tube with oil. (Ref. FIG. 32) Cap the bypass oil tube and monitor the oil level in

the pressure-out tube.

(a) A decrease in the tube oil level indicates a probable internal leakage of the oil pump

and/or leakage past the O-rings located at the pump ports. Ascertain fault and replace

part as necessary. (Refer to applicable part of Gearbox Disassembly and Assembly.)

(b) If the oil level in the tube does not drop, the oil filter housing may be the cause of leakage.

Replace part if any of the following conditions are noted and local repair not practical.

Accesses wear at the ID of the oil-out port.

Pressure regulating valve seat or poppet damage.

Page 127

O-ring seal deterioration.

CAUTION: REMOVE CAP FROM BYPASS TUBE BEFORE INSTALLING THE OIL

FILTER HOUSING.

(7) Install acceptable oil filter housing in accordance with Gearbox and Assembly.

68.

Engine Operated With No Oil Pressure

Any engine operated for more than 30 seconds without oil pressure must be removed and sent to an

Rolls-Royce Authorized Maintenance Center for disassembly and inspection as defined by the

250-C18 Series Engine Overhaul Manual, Publication No. 5W3.

69.

Carbon Buildup Inspection

A. Inspect for carbon particles in the engine or oil system as follows:

(1) Drain the oil from the engine and from the oil tank. Drain oil through a clean cloth which is

suitable for filtering (detecting) carbon particles.

(2) Inspect the No. 8 bearing and sump area. Do not remove the oil tube and nozzle. (Refer to

appropriate part of Flushing the Gas Producer Turbine Support Pressure Oil Passage

Flushing.)

(3) Rotate the gas producer rotor. Listen for abnormal noise and visually inspect for damage.

(4) If carbon buildup is detected during the oil, sump, and rotor inspection, inspect and clean if

necessary, the power turbine support scavenge oil strut. (Refer to of Power Turbine Support

Scavenge Oil Strut Inspection and Cleaning.)

70.

Magnetic Plug Inspection.

WARNING: IF A MAGNETIC PLUG WARNING LIGHT COMES ON DURING FLIGHT, LAND AND

INSPECT THE MAGNETIC PLUGS AS SOON AS POSSIBLE. THIS LIGHT IS AN

INDICATION OF CONDITIONS WHICH COULD CAUSE ENGINE FAILURE. WHEN

FLYING A MULTI-ENGINE AIRCRAFT, REDUCE THE AFFECTED ENGINE OUTPUT

POWER TO THE MINIMUM REQUIRED FOR FLIGHT AND LAND AS SOON AS

PRACTICABLE. IF THE LIGHT IS ACCOMPANIED BY ABNORMAL NOISES, OIL

PRESSURE OR TEMPERATURE, AND SINGLE-ENGINE FLIGHT CAN BE

MAINTAINED, SHUT DOWN AFFECTED ENGINE AND LAND AS SOON AS

PRACTICABLE. IF SINGLE-ENGINE FLIGHT IS NOT POSSIBLE, REDUCE POWER

OF AFFECTED ENGINE TO THE MINIMUM AND LAND AS SOON AS POSSIBLE.

AFTER LANDING, INSPECT THE MAGNETIC PLUGS ON THE AFFECTED ENGINE

FOR METAL CONTAMINATION PRIOR TO FURTHER ENGINE OPERATION.

Two indicating type magnetic drain plugs are installed in the power and accessories gearbox. If a

warning light is received in the cockpit or at scheduled maintenance intervals, remove and visually

inspect the magnetic drain plugs. The contamination conditions which may be encountered on the

magnetic plugs are defined as follows:

(1) Paste.

(a) Paste is the result of fine soft particles which come from normal wear due to gear mesh,

bearing rotation and/or spline engagement. These particles mix with oil or soft carbon to

form paste.

(b) This condition is normal and is the reason for the 100 hour cleaning interval. Paste

generally does not cause a warning light. If a light is encountered, perform a Magnetic

Plug Inspection.

filtered shop air. Reinstall, Torque to 60-80 lb in. (6.8-9.0 N^.m).

NOTE: Heavy accumulations of paste require inspection and cleaning of the magnetic

plugs at intervals of 25 to 100 hours. Cleaning paste from the plugs is

necessary to ensure that small chips, flakes and/or slivers can be detected.

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(2)

Magnetic Particles.

(a) Magnetic particles and debris, chips, flakes, and slivers are possible indications of bearing

or gear failure and/or abnormal wear within the engine.

(b) Chips or flakes exceeding 1/32 in. (0.79 mm) diameter or more than 4 slivers per event

are not acceptable.

Remove engine and send to an Rolls-Royce Authorized Maintenance Center.

Prior to operation of the replacement engine, perform the following:

a If a scavenge oil filter is installed and the filter bypass button has not extended,

clean the airframe provided engine oil lines and replace the scavenge oil filter.

b Confirm proper operation of the scavenge oil filter impending bypass indicator

by performing the functional check per Facet Service Bulletin No. 090589 (ref.

Rolls-Royce CSL 168) for aircraft equipped with this type of external scavenge

filter system.

c If the scavenge oil filter has bypassed if the impending bypass fails the

functional test, or if no scavenge filter is installed, clean or replace the scavenge

oil filter, oil cooler, oil tank, and lubrication system oil lines per the airframe

manufacturer’s instructions. Drain and replace the engine oil. (Refer to Engine

Oil Change.)

acceptable.

If a warning light is encountered, refer to sub para (3).

Reinstall the magnetic plug and torque to 60-80 lb in. (6.8-9.0 N.m).

(3)

Perform the following maintenance action as a result of a magnetic chip light indication.

(a)

Clean the magnetic drain plugs. Perform a 30 minute ground run at power with the rotor

turning. Observe engine operation limits and chip warning lights.

(b)

If operation is normal, remove, inspect, clean, and reinstall both chip detectors. Return

engine to service.

(c)

If chips or flakes are less than 1/32 in. (0.79 mm) diameter or fewer than four slivers are

encountered during the 30 minute run, perform the maintenance actions in the next step.

(d)

If a chip light is encountered during the first 30 minute ground run, the following steps

must be taken before the second 30 minute ground run.

Drain oil.

Clean engine oil filter.

Flush the aircraft oil system to remove any circulating debris.

Clean engine chip detectors.

Service engine oil system with fresh, clean oil.

Perform a 30 minute ground run at power with rotor turning. Observe engine

operating limits and chip warning lights. If operation is normal then, remove, inspect,

clean, and reinstall both chip detectors. Return engine to service.

If a chip light is encountered during the second 30 minute ground run, remove the

engine from service and send to an Rolls-Royce Authorized Maintenance Center.

Clean the aircraft engine oil system per step 2 (b) 2).

NOTE: If warning light illuminates within the next eight operating hours following a

30 minute ground run, and the cause is determined to be an accumulation

of magnetic particles and debris (chips, flakes or slivers), remove the

engine and send to an Rolls-Royce Authorized Maintenance Center. Tag

engine noting cause for rejection. This note is applicable only after sub

para (3) (d) is complied with (reference oil drain and flush); otherwise this is

another event.

Page 130

(e) A maximum of four (4) occurrences of a magnetic chip warning light encountered within

any 50 hours of engine operation, requires removal of the engine for shipment to an

Rolls-Royce Authorized Maintenance Center.

NOTE: Magnetic light indications where only paste is present must still be counted in

the four and 50 hour criteria.

71.

Magnetic Plugs Operational Check

A. If magnetic plugs are removed for scheduled maintenance, perform an operational check prior to

reinstallation. Connect harness lead and bridge plug with a suitable conductor. Check each plug

separately for proper cockpit indication.

B. Reinstall magnetic plug, Torque to 60-80 lb in. (6.8-9.0 N.m).

C. If quick disconnect magnetic chip detector plugs are installed, inspect the locking pins and flanged

inserts for wear as follows:

(1) Inspect the three locking pins for proper condition and wear. The minimum allowable pin

diameter on any one pin is 0.070 in. (1.78 mm). The plug should be replaced by a serviceable

item if any one or more pin is worn to less than 0.070 in. (1.78 mm) diameter. (Ref. FIG. 33)

NOTE: The point of wear is usually on the side of the pin nearest the spring loaded ring.

Push the ring back to obtain better access for inspection.

(2) Inspect the insert for proper condition and wear of the locking cam slot. The material

remaining between the end of the cam slot and the edge of the insert must be more than 0.068

in. (1.73 mm). (Ref. FIG. 33) Replace the insert with a serviceable item if the area is worn to

less than 0.068 in. (1.73 mm). (Refer to Commercial Engine Bulletin 250-C18 CEB-200 for

details of insert replacement.)

NOTE: If local personnel, tooling, and facilities are inadequate, send the gearbox assembly

or propeller reduction gearbox assembly to an Rolls-Royce Authorized Maintenance

Center.

Quick Disconnect Magnetic Plug Wear Limits

FIG. 33

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(3) Reinstall the serviceable magnetic plug.

(4) Reconnect the electrical wiring as applicable.

(5) Replenish engine oil as necessary.

(6) Make appropriate entry on Inspection Check List relative to the magnetic plug inspection.

72.

Tedeco Manual Zapper

When operating an aircraft utilizing the Tedeco Manual Zapper the following applies:

(1)

First Time Chip Light Comes ON.

The “Chip Pulse” switch should be activated to “ON”.

(a) If the chip light goes out after activation of the “Chip Pulse” switch, continue the flight,

make a log book entry accordingly and observe engine operation and warning lights.

(b) If the chip light remains on after activation of the “Chip Pulse” switch, land and inspect the

magnetic plugs as soon as possible. This light is an indication of conditions which could

cause engine failure. When flying a multi-engine aircraft, reduce the affected engine

output power to the minimum required for flight and land as soon as practical. If the light

is accompanied by abnormal noises, oil pressure or temperature and single-engine flight

can be maintained, shut down affected engine and land as soon as practical. If

single-engine flight is not possible, reduce power of affected engine to minimum and land

as soon as possible. After landing, inspect the magnetic plugs on the affected engine for

metal contamination prior to further engine operation. Refer to Magnetic Plug Inspection

and make a log book entry accordingly.

light comes on, land as soon as possible. This light is an indication of conditions which

could cause engine failure. When flying a multi-engine aircraft, reduce the affected

engine output power to the minimum required for flight and land as soon as practical. If

the light is accompanied by abnormal noises, oil pressure or temperature and

single-engine flight can be maintained, shut down affected engine and land as soon as

practical. If single-engine flight is not possible, reduce power of affected engine to the

minimum and land as soon as possible. After landing, inspect the magnetic plugs of the

affected engine for metal contamination prior to further engine operation. Refer to

Magnetic Plug Inspection and make a log book entry accordingly.

(2)

Second Time Chip Light Comes ON.

If the chip light comes on a second time within 50 hours of the first time, follow the procedure

in sub para (1).

(3)

Third Time Chip Light Comes ON.

If the chip light comes on a third time within 50 hours of the first time, do not actuate “Chip

Pulse”. Land and insect the magnetic plugs as soon as possible. This light is an indication of

conditions which could cause engine failure. When flying a multi-engine aircraft, reduce the

affected engine output power to the minimum required for flight and land as soon as practical.

If the light is accompanied by abnormal noises, oil pressure or temperature and single-engine

flight can be maintained, shut down affected engine and land as soon as practical. If

single-engine flight is not possible, reduce power of affected engine to the minimum and land

as soon as possible. After landing, inspect the magnetic plugs on the affected engine for

metal contamination prior to further engine operation. Refer to Magnetic Plug Inspection and

make a log book entry accordingly.

NOTE: If a magnetic drain plug warning light received in the cockpit is confirmed to be

caused by an indicating system malfunction and no metal is found on the magnetic

drain plugs, this chip light incident does not count toward the total of four chip lights

in 50 hours.

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(4) Fourth Time Chip Light Comes ON.

If the chip light illuminates a fourth time within 50 hours, do not activate “Chip Pulse.” Land a

soon as possible. This light is an indication of conditions which could cause engine failure.

When flying a multi-engine aircraft, reduce the affected engine output power to the minimum

required for flight and land as soon as practical. If the light is accompanied by abnormal

noises, oil pressure or temperature and single-engine flight can be maintained, shut down

affected engine and land as soon as practical. If the single-engine flight is not possible,

reduce power of affected engine to the minimum and land as soon as possible. Remove the

affected engine and send it to an Rolls-Royce Authorized Maintenance Center. Tag engine

noting the reason for rejection.

(5) If the 50 hour time period is obtained with two or fewer chip light indications, a new 50 hour

sequence begins and appropriate adjustments to log entries should be made for previous 50

hour sequence.

(6) Suggested Logging Procedure For Chip Indications.

(a) All chip indications, whether physically inspected or zapped, must appear in the Engine

Maintenance Log. The maintenance records which are available to the pilot should reflect

the total number of chip indications for the previous 50 hours so that the pilot can initiate

the appropriate procedure if a chip light indication is received in the cockpit during the

day’s operational period.

73.

Engine Oil Change

Change the engine oil at the time interval specified in Table 8 or when oil contamination is

encountered. Refer to Magnetic Plug Inspection.

(1)

Drain the engine oil supply tank and engine oil cooler. Where the installation permits, inspect

the oil tank and cooler for carbon and sludge deposits. If deposits are found, remove the oil

tank or oil cooler in accordance with the aircraft manufacturers recommendations. Clean the

tank or cooler using a suitable solvent.

(2)

Remove the magnetic drain plugs from the power and accessories gearbox. Allow residual oil

to drain from the magnetic plug openings in the gearbox. Inspect the plugs in accordance with

Magnetic Plug Inspection. Clean the plugs with solvent. Dry with a clean cloth.

(3)

If an accumulation of magnetic particles, debris, chips, flakes or slivers is the cause for oil

change, remove, disassemble, clean and inspect the oil pressure reducer at the compressor

front support inlet to the number one bearing. Refer to Compressor Front Bearing and/or Oil

Seal Replacement (Engine Removed)for inspection and cleaning details.

(4)

Remove the oil filter and O-ring on applicable configurations from the filter housing. Use

6798860 puller to remove filter cap. Discard the O-ring. Thoroughly clean the oil filter cavity

of all residual oil and sludge. Take the necessary precautions to prevent residual oil from

entering the engine cavity or standpipe. Clean the oil filter. Refer to Oil Filter Maintenance.

NOTE: Some engine bearings feature silver-plated separators. If minute silver particles are

found in the engine oil filter, clean and reinstall the filter. These minute particles are

due to normal bearing wear and are not cause for further corrective action.

(5)

Install the magnetic drain plugs. Use new O-rings lubricated with engine oil. Torque plugs to

60-80 lb in. (6.8-9.0 N.m) and secure with lockwire.

(6)

Install new or cleaned oil filter with new O-ring. Fill the filter cavity with appropriate engine oil.

Install the filter cap with a new O-ring which has been lubricated with engine oil. Retain cap

with two nuts and washers. Torque nuts to 30-40 lb in. (3.4-4.5 N.m).

Page 133

Nov 1/98

Rolls-Royce Engine 250–C18, 250–C18A, 250–C18B, 250–C18C. Operation and Maintenance Manual (2003) - page 7