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

TABLE 9

Special Inspections - continued

Item

Occurrence

Component or System

Required

Action

Oil spray on 1st-stage wheel

Turbine

Engine inactive more than 5 days

Compressor

Engine inactive more than 45 days

Oil system

Fuel system

As dictated by performance

Fuel control P_c filter

System P_c filter

Vibration

Compressor

Gearbox

Engine submerged while in operation

Compressor

Turbine

On condition inspection

Power and accessories gearbox

Lightning strike

Engine, general

First 50 hours of operation on new, re-

Oil system

paired, or over-hauled engine

Fuel control system component remove/re-

Fuel control system

placement

Fuel system contamination. Known high

Fuel pump filter

amount of particles or microbiologicals.

Fuel control filter

Fuel nozzle strainer

NOTE: The letter designations in the Required Action column refer to the applicable Description of

Inspection.

Description of Inspections

Engine, General

Any time the engine is removed from the aircraft, inspect the compressor inlet for foreign object

damage or condition. Clean and flush all aircraft drain lines. Wash the outside of the engine

with mineral spirits. Touch up paint where peeling or chipping is evident. (Refer to Corrosion

Treatment and Surface Finish Repair.)

After a hard landing, inspect the complete engine. (Refer to Hard Landing Limits.)

After the main or tail rotor strikes an object or the engine N₂ power train is subjected to abnor-

mal shock loading, a sudden stoppage inspection must be performed. (Refer to Sudden Stop-

page Inspection.)

After a lightning strike, inspect the complete engine. (Refer to Lightning Strike Inspection.)

Rigid Tubes and Accumulators

Inspect rigid tubes and/or accumulators any time they are removed. Replace tube if any cracks

(dye check) are detected or if the tube has kinks or dents which could affect seating or integrity.

(Refer to Rigid Tube Installation.) Replace accumulators if leaks are found. (Refer to Accumu-

lator Maintenance.)

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Description of Inspections - continued

Compressor

After engine operation with inlet air restricted due to foreign objects, replace the compressor.

(Refer to Compressor Inlet Air Blockage.)

If the engine is submerged in water while in operation, return the complete engine to an over-

haul facility for replacement of all compressor and turbine wheels. (Refer to Engine Submerged

While in Operation.)

After engine operation in snow, ice, or water, inspect the compressor inlet (without disassembly

of engine parts) for damage due to ingestion of snow or ice buildup. (Refer to Snow Ingestion

Inspection.)

After suspected foreign object damage, inspect the compressor rotor blades and stator vanes.

(Refer to Blade Damage, and Vane Damage.)

After engine operation in an erosive environment, inspect compressor blades, vanes, and plas-

tic for erosion.

(Refer to Erosion Inspection.)

NOTE: If the aircraft is subjected to sand or dust ingestion, periodic compressor erosion inspection

is recommended. The frequency of the inspection should be based on the frequency and

degree of ingestion and condition of the compressor at the last inspection. Experience has

shown that the bottom half of the compressor case is more prone to erosion.

If cracks are detected in the scroll at the anti-ice valve; if discharge air tube inserts are loose or

backing out of the scroll, or if vibration is suspected, inspect for possible vibration causes. (Re-

fer to Vibration Inspection.

If the engine will be shut down for more than five calendar days, preserve the compressor. (Re-

fer to Compressor Preservation.)

Anti-icing Valve

Any time the compressor is removed from the engine, inspect the anti-icing air valve for wear or

damage. (Refer to Anti-icing Air Valve.)

Turbine

After suspected foreign object damage, inspect the first-stage turbine blades and vanes. (Refer

to Turbine Blade and Vane Inspection.)

After engine operation at temperature exceeding the operating limits requiring turbine inspection

in Section II Table 1, inspect the 1st-stage turbine wheel in accordance with Turbine Blade

Damage. Inspect the 1st-stage turbine nozzle in accordance with Table 14. Inspect the com-

bustion liner in accordance with Table 15. Record temperature and duration in the Engine Log.

NOTE: If either the 1st-stage turbine wheel or 1st-stage nozzle is rejected because of

overtemperature, the complete turbine (gas producer and power turbine) must be removed

and sent to a Rolls-Royce Authorized Maintenance Center for inspection.

After exceeding the starting temperature limits of Section II, Table 1, where turbine inspection is

the recommended action, inspect the 1st-stage turbine wheel in accordance with Turbine Blade

Damage. Inspect the 1st-stage turbine nozzle in accordance with Table 14. Inspect the com-

bustion liner in accordance with Table 15. (Refer to Hot Start Inspection.) Record temperature

and duration in the Engine Log.

NOTE: If either the 1st-stage turbine wheel or 1st-stage nozzle is rejected because of

overtemperature, the complete turbine (gas producer and power turbine) must be removed

and sent to a Rolls-Royce Authorized Maintenance Center for inspection.

Any time the turbine is removed from the engine, inspect the internal splines of the power train

drive helical gear.

(Refer to Helical Gear Internal Spline Inspection.)

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Description of Inspections - continued

If the engine is submerged in water while in operation, return the complete engine to an over-

haul facility for replacement of all compressor and turbine wheels. (Refer to Engine Submerged

While in Operation.)

Anytime the turbine is removed from the engine, inspect the turbine-to-pinion gear coupling

shaft splines and the power turbine outer shaft splines. (Refer to Power Turbine Shaft Spline

Inspection and Turbine-to-Pinion Gear Coupling Shaft Spline Inspection.)

Thermocouples

After engine operation at temperatures exceeding the operating limits requiring turbine inspec-

tion in Section II, Table 1, inspect the thermocouples. (Refer to Thermocouples.)

Outer Combustion Case

Anytime the turbine is removed from the engine, inspect the outer combustion case. (Refer to

Outer Combustion Case Inspection.)

Combustion Liner

Anytime the turbine is removed from the engine, inspect the combustion liner. (Refer to

Table 15.)

Fuel Control System

v1.

Anytime a fuel control system component is reinstalled on a pneumatic line when disconnected,

a pneumatic leak check of the control system is required. (Refer to Fuel Control System Pneu-

matic Leak Check.)

Compressor Discharge Air Tubes

Anytime the turbine is removed from the engine, inspect the compressor discharge air tubes for

dents, cracks, or wear. (Refer to Compressor Discharge Air Tubes Inspection.)

Burner Drain Valve

Anytime the turbine is removed from the engine, remove, clean and inspect the burner drain

valve. (Refer to Burner Drain Valve Maintenance.)

Gearbox

Anytime the compressor is removed from the engine, inspect the mounting inserts on the gear-

box for looseness. Refer to Compressor Insert Inspection. If loose inserts are detected, check

for possible vibration causes. (Refer to Vibration Inspection.)

Anytime the power and accessories gearbox housing is separated from the gearbox cover at an

Authorized Maintenance Facility and the Log Book indicates 3500 hours have elapsed since the

gears were new or last magnafluxed, magnetically inspect all gears. (Refer to paragraph 32.)

Oil System

aa.

Drain oil from the system and refill using the oils specified in Approved Oils, Section I. (Refer to

Table 8 for time interval.) Remove, clean, and reinstall the oil filter at each oil change.

ab.

If engine is inactive for more than 45 days, preserve oil system in accordance with Oil System

Preservation.

ac.

Anytime the engine oil temperature limit has been exceeded, take the appropriate maintenance

action given in Oil Temperature Limit Exceeded.

ac1.

Anytime the engine is operated for more than 30 seconds without oil pressure, maintenance is

required. (Refer to Low Oil Pressure Operation.)

Oil Filter

ad.

At each oil change, remove, clean, and reinstall the oil filter. (Refer to Oil Filter Maintenance.)

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Description of Inspections - continued

Turbine

ae.

Send the turbine to an overhaul facility for replacement of the first-stage wheel if oil has leaked

or been forcibly sprayed onto the wheel during operation of the engine.

Turbine Pressure Oil System Check Valve

af.

Anytime the turbine is removed from the engine, clean and inspect the check valve. (Refer to

Turbine Pressure Oil System Check Valve.)

Fuel Pump Filter

CAUTION: WHEN THERE IS EVIDENCE THAT THE FUEL PUMP FILTER HAS BEEN BYPASSED,

THE MAINTENANCE ACTIONS DESCRIBED IN ITEM AH (FUEL CONTROL

STRAINER), AND ITEM AL (FUEL NOZZLE STRAINER) MUST BE COMPLIED WITH.

ag.

The engine driven fuel pump is equipped with a throw-away filter element with a maximum re-

placement interval specified in the Scheduled Inspections (Table 8). If the filter shows signs of

contamination to the point of possibly bypassing, or if an impending bypass indication has been

noted (some aircraft may incorporate this system), replace the filter element. (Refer to Fuel

System Filter Maintenance for filter replacement instructions.)

Fuel Control Strainer

CAUTION: IF THE FUEL CONTROL STRAINER SHOWS EVIDENCE OF CONTAMINATION,

RETURN THE FUEL CONTROL TO AN AUTHORIZED MAINTENANCE FACILITY FOR

CLEANING AND INSPECTION. ALSO, INSPECT THE FUEL NOZZLE STRAINER FOR

CONTAMINATION. IF CONTAMINATION IS FOUND ON THE STRAINER, RETURN THE

FUEL NOZZLE TO AN AUTHORIZED FACILITY FOR CLEANING AND TESTING.

REFERENCE MUST ALSO BE MADE TO THE AIRFRAME MAINTENANCE MANUAL

FOR FUEL SYSTEM MAINTENANCE FOLLOWING FUEL CONTAMINATION.

ah.

Anytime fuel pump filter bypass is known or suspected to have taken place, inspect and if re-

quired, clean the fuel filter element in the gas producer fuel control.

(Refer to the Gas Producer

Fuel Control Fuel Strainer Cleaning.)

Fuel Control P_c Filter, P_x and P_y Bleeds

ai.

When dictated by engine performance, remove, clean and reinstall the fuel control P_c filter and

P_x and P_y bleeds. (Refer to Gas Producer Fuel Control Air Circuit Cleaning.)

Fuel System P_c Filter

aj.

When dictated by engine performance, remove, clean and reinstall the fuel system P_c Filter.

(Refer to P_c Filter Maintenance.)

Accumulators

ak.

When an engine is replaced, transfer the accumulators to the replacement engine. While re-

moved, clean and test accumulators in accordance with Accumulator Maintenance procedures.

Fuel Nozzle Strainer

CAUTION: IF THE STRAINER HAS BEEN CONTAMINATED OR HAS COLLAPSED OR BUCKLED,

RETURN THE FUEL NOZZLE TO AN AUTHORIZED MAINTENANCE FACILITY FOR

CLEANING AND TESTING. THIS ALSO REQUIRES THAT THE FUEL CONTROL BE

SENT TO AN AUTHORIZED MAINTENANCE FACILITY FOR INTERNAL CLEANING.

REFERENCE MUST ALSO BE MADE TO THE AIRFRAME MAINTENANCE MANUAL

FOR FUEL SYSTEM MAINTENANCE FOLLOWING FUEL CONTAMINATION.

al.

Anytime high pressure fuel filter bypass is known or suspected to have taken place, or evidence

of contamination is found in the fuel pump, fuel control or governor, inspect the fuel nozzle

strainer for contamination.

(Refer to the strainer inspection, Fuel Nozzle Maintenance.)

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Description of Inspections - continued

Turbine-to-Compressor Coupling

am.

After (1) compressor removal, (2) turbine removal, or (3) turbine separation at the exhaust col-

lector-to-power turbine support, inspect the splines on both ends of the coupling. (Refer to Tur-

bine-to-Compressor Coupling Spline Inspection.)

Spur Adapter Gearshaft

an.

Anytime the compressor is removed, inspect the aft splines of the spur adapter gearshaft. (Re-

fer to Spur Adapter Gearshaft Aft Spline Inspection.)

Fuel System

ao.

If engine is inactive for more than 45 days, preserve fuel system in accordance with Fuel Sys-

tem Preservation.

ap.

Check oil filter for contamination. If debris is found, proceed as follows:

Drain the oil system. Pay particular attention to any metallic debris in the oil. Swab the oil tank

and note any foreign material.

Flush the engine oil system.

Clean the oil filter.

Reinstall the filter and top off with fresh oil.

Perform a 30 minute ground run at power as described in para 154, Magnetic Plug Inspection.

After ground run, remove and inspect the filter. If the filter shows no accumulated debris, the

aircraft may be released for flight. A check of the engine oil filter at 10 hour intervals for the

next 30 hours of operation is recommended to determine if additional particles have accumu-

lated in the filter.

If decreased oil pressure is noticed during operation, check engine oil filter for debris at that

time.

24.

Vibration Inspection

A. If engine vibration is suspected, or any of the vibration symptoms listed in the 100-hour inspection

(Table 8 ) are encountered, inspect the compressor and return it to repair/overhaul if any of the

following conditions are encountered:

(1) Remove the top half of the compressor case and check all blades and vanes for possible

foreign object damage and/or for bent or distorted vanes. Blade and vane condition must be

within the limits given in Blade and Vane Inspection.

(2) Remove the compressor assembly from the engine. Check the spur adapter gearshaft for

excessive wear on the 17 tooth gear or splines. Refer to Table 9 for spline inspection criteria.

(3) Check the scroll outlet ports (turning vanes) for evidence of damage. Damage is indicative of

impeller vane tip or shroud failure.

25.

Hard Landing Limits

A. Make a visual inspection of the installed engine for external damage from airframe components

after any hard landing.

B. Engines, fuel controls and governors that have sustained landing forces exceeding 10_g shall be

sent to an overhaul facility. The airframe conditions which can be used as an indication that the 10_g

landing force limit has been exceeded are as follows:

(1) Bell 206A Jet Ranger. Airframe landing skids and cross tubes deformed to a degree that the

cabin fuselage touches (or shows evidence of having touched) the ground.

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(2) Fairchild Hiller FH-1100. Engine airframe mounting brackets deformed.

(3) Hughes Model 500. Pilot and co-pilot seat metal box frames buckled, dish panned, and/or

wrinkled.

26.

Sudden Engine Stoppage Inspection

The following specific items and/or functions are the minimum required actions when performing a

sudden stoppage/engagement inspection. Each incident should be judged on an “as required”

basis possibly requiring more than these minimum requirements. Engines involved in sudden

stoppage/engagement do not require overhaul automatically. This judgment is the responsibility of

the service facility performing the inspection.

NOTE: If the engine has to be removed from the airframe as a result of the main rotor sudden

stoppage/engagement (specified in paragraphs following), the operator should take care

to provide the distributor or Rolls-Royce Authorized Maintenance Center (AMC) with all

the details about the incident. This information should include a description of damage to

the airframe power train and mounts, as well as any other pertinent information.

(1)

If a drive system component malfunctions or the aircraft main rotor blade(s) strike an object,

and sustains damage which is field repairable in accordance with aircraft manufacturer’s

recommendations, perform the following:

(a) Inspect magnetic plugs for metal accumulation. (Refer to Magnetic Plug Inspection.)

(b) Inspect the engine inlet for foreign objects.

(d) Motor the engine and check for unusual noise.

(e) Operate the engine for 30 minutes on the ground then check the magnetic plugs for metal

accumulation. (Refer to Magnetic Plug Inspection.)

On twin engine aircraft, each engine should be operated at 100 percent NR and flat

pitch.

On single engine aircraft, engine should be operated at power required to make

aircraft light on its skids.

(2)

If a drive system component malfunctions or the aircraft main rotor blade(s) strike an object

during operation and sustains damage that requires removal from service of the main rotor

blade(s) or any aircraft main rotor drive system component, remove the engine and perform

the following:

(a) Inspect the turbine shaft to pinion gear coupling, power turbine outer shaft and pinion gear

splines for evidence of damage, wear, and acceptability for further service. (Refer to

Power Turbine Outer Shaft Spline Inspection; Power Train Pinion Helical Gear Spline

Inspection and Turbine-to-Pinion Gear Coupling Shaft Inspection.) Magnetic particle

inspect the turbine shaft-to-pinion gear coupling.

(b) Send the accessory gearbox to an authorized overhaul facility for inspection per the

250-C18 Series Overhaul Manual, Pub. No. 5W3.

(d) After engine reassembly, operate the engine for 30 minutes on the ground; then, check

the magnetic plugs for metal accumulation. (Refer to Magnetic Plug Inspection.)

On twin engine aircraft, each engine should be operated individually at 100 percent

NR and flat pitch.

On single engine aircraft, engine should be operated at power required to make light

aircraft on its skids.

NOTE: Test cell run may be substituted for the above 30 minute ground run.

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If a drive system component malfunctions or the aircraft main rotor blade(s) strike an

object during operation and the engine or transmission mounts are fractured or

misaligned, return engine to a Rolls-Royce Authorized Maintenance Center (AMC)

for complete overhaul with the following exceptions. The accessories listed below

must be bench tested in accordance with the 250-C18 Series Overhaul Manual,

Pub. No. 5W3, and meet all overhaul limits.

a Bleed Valve

b Engine Driven Fuel Pump

c Fuel Nozzle

d Anti-Ice Valve

e Electrical/Electronic Device

Fuel Control

g Power Turbine Governor

27.

Compressor Inlet Air Blockage

Replace the compressor assembly if the engine has been operated with inlet air restricted due to foreign

objects or materials which have become lodged in the compressor inlet. Tag the replaced compressor to

show that the cause of removal was inlet air blockage. Conditions which constitute blockage are as

follows:

A. Foreign objects or materials found in the inlet during inspection of the aircraft when not in operation.

If it can be determined that the blockage was not there during the last operation of the engine,

remove the foreign object or material and leave the compressor in service.

B. Power loss encountered following a restriction at the compressor inlet area while the engine is in

operation. Blockage in flight can usually be verified by inspection after landing (blockage still

exists). However, some blockage may be followed by ingestion before inspection can take place.

Objects or materials which were large enough to have stopped at the inlet guide vanes before

ingestion, or which cause a noticeable raise in TOT, can be considered to have caused compressor

inlet blockage.

28.

Engine Submerged While In Operation

A. If the engine has been submerged in water while in operation, proceed as follows:

(1) Flag the engine indicating that it encountered submersion while in operation.

(2) Return the entire engine to an overhaul facility as soon as possible for replacement of all

compressor and turbine wheels.

29.

Hot Start Inspection

A. When the engine starting temperature limits of Section II, Table 1 are exceeded and turbine

inspection is the recommended maintenance action, proceed as follows:

(1) Remove the outer combustion case and combustion liner. (Refer to Replacing the Combustion

Liner.)

(2) Inspect the nozzle in accordance with items 1 and 2 of Table 14.

(3) Inspect the 1st-stage turbine wheel. (Refer to Blade Damage.)

(4) Inspect the combustion liner in accordance with Table 15.

(5) Reassemble the engine. (Refer to Combustion Liner Replacement.)

30.

Snow Ingestion Inspection

A. Perform the following:

(1) Inspect the engine for snow, ice, or water damage as follows:

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(2) Obtain access to the compressor inlet but do not disassemble any engine parts.

(3) Replace the compressor assembly if any mechanical damage, distortion, or bending is

detected on the compressor front support vanes or 1st-stage rotor blades.

31.

Erosion Or Corrosion Inspection

If the aircraft is frequently subjected to sand or dust ingestion or operated in a corrosive environment

(salt laden or other chemically laden atmosphere such as pesticides, herbicides, sulfur, industrial

pollutants, etc.), inspect compressor blades, vanes, and case plastic coating for erosion or corrosion

damage. Engines operated in a corrosive environment should be subjected to daily fresh water

compressor rinses. (Refer to Compressor Blade Damage, Vane Damage, Case Plastic Coating

Inspection and Case Replacement.)

NOTE: If the aircraft is subjected to sand, dust or other small particle ingestion, periodic compressor

erosion inspection is recommended. The frequency of the inspection should be based on the

degree of ingestion and condition of the compressor at the last inspection. The need for more

frequent compressor rinse may also be indicated.

NOTE: See CSL-141 for instructions on suggested contamination removal using water only and for

maps of operating areas with salt laden air.

32.

On Condition Inspection-Power And Accessories Gearbox

A. Anytime the gearbox housing is separated from the cover, all gears shall be magnetically inspected

if the Log Book indicates that more than 3500 hours have elapsed since the gears were new or last

magnafluxed. (Refer to the engine Overhaul Manual, Publication No. 5W3, for inspection criteria.)

NOTE: Record compliance with this inspection in the appropriate section of the Log Book.

Include date and hours.

33.

Lightning Strike Inspection

Aircraft lightning strikes occur when the airframe can serve as a least-resistance bridge for the

electrical bolt as it travels through the air. Consequently, aircraft extremities (tail pylon, blades,

nose, landing gear, etc.) typically act as points of entry or exit. However since the exact electrical

path through the aircraft may not be readily traceable following a strike, the following guidelines are

recommended:

(1) In the event of a lightning strike in the immediate vicinity of the engine(s) (as evidenced by

charring, burn marks or pitting associated with electrical arcing on the engine cowl,

compartment or inlet) remove the engine(s) prior to further flight and send them to an

Rolls-Royce-approved repair facility for detailed teardown and inspection.

(2) Where the aircraft is known or suspected of having been involved in a lightning strike and

entry/exit points either cannot be determined or appear remote to the engine(s), perform the

following:

(a) Inspect the engine compartment for evidence of lightning strike damage.

(b) Manually rotate N₁ and N₂ systems and check for binding and abnormal noise.

Inspection, and Engine Oil Filter Maintenanc.)

(d) Operate the engine for 30 minutes on the ground and recheck the magnetic plugs for

metal accumulation. (Refer to Magnetic Plug Inspection.)

On twin engine aircraft, each engine should be operated individually at 100% NR and

flat pitch.

On single engine aircraft, engine should be operated at power required to make

aircraft light on its skids.

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(e) Listen for abnormal noise on coastdown and abnormally short coastdown time.

34.

Systems Maintenance

A. System maintenance includes the inspections, cleaning, replacements, and adjustments

accomplished on the items making up the major systems of the engine.

35.

Fuel, Control Air, And Oil Tubes Inspection

A. Inspect tubes for dents, chafing or cracks.

(1) Reject tubes with cracks (dye check) in any area.

(2) Reject tubes having dents or chafing on the flared ends or on the retention clamps.

(3) Reject tubes with dents exceeding 1/8 in. (3 mm) depth or having a sharp radius.

(4) Install rigid tubes in accordance with Rigid Tube Installation.

36.

Fuel System

WARNING: WATER OR CONTAMINATION IN THE FUEL CAN CAUSE FLAMEOUT OR POWER

LOSS.

WARNING: AIR LEAKS IN THE FUEL SYSTEM OR THE PNEUMATIC SENSING SYSTEM CAN

CAUSE FLAMEOUTS, POWER LOSS OR OVERSPEED.

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

FITTINGS AND TUBES COULD RESULT IN AN ENGINE FAILURE.

WARNING: PERFORM A VACUUM CHECK OF FUEL SYSTEM LINES AND COMPONENTS

ANYTIME A FUEL SYSTEM COMPONENT IS REMOVED OR REPLACED TO ENSURE

NO ENGINE OR AIRFRAME FUEL SYSTEM LEAKS ARE PRESENT.

Fuel system maintenance includes: replacing the fuel filter; inspecting and cleaning the fuel nozzle;

cleaning the P_c filter and P_x and P_y bleeds; inspecting and cleaning the fuel control filter assembly;

adjusting the gas producer fuel control; replacing the gas producer fuel control; the power turbine

governor, the fuel pump and filter assembly, and the double check valve; inspecting and cleaning

the accumulators; and purging the fuel system.

Fuel System Air Leaks. The two principal reasons for fuel system air leaks are loose lines and

damaged or impaired fittings.

NOTE: Loose lines can develop from improperly tightened B-nuts. Damaged fittings are the

result of incorrect handling or improper installation procedures. Insufficient tightening of

the B-nut allows wear of the fitting through normal operating vibrations applied to a loose

flare.

(1) When a loose line is detected, proceed as follows:

(a) Remove the line and check the flares for wear, bends, dents, feathered edges or other

deformities.

(b) Inspect nipple portion of fitting for damage, grooves or wear. Detect grooves in the

mating surface by placing a small metal straight edge on the beveled surface and viewing

for gaps.

Tube clamping should be in accordance with the 250-C18 Illustrated Parts Catalog

(Pub. No. 5W4).

If a tube requires replacement, the fitting to which it mates should also be replaced.

37.

Fuel System Air Purging

A. Purge fuel system air (can be trapped in the fuel system) when any of the following conditions are

encountered:

(1) The low pressure fuel filter element or the fuel pump assembly has been replaced.

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(2) The fuel lines have been opened (anywhere between the fuel tank and the fuel nozzle).

(3) The engine has flamed out because of fuel exhaustion.

(4) The engine has been motored without fuel in the tank.

(5) The fuel pump fuel filter bowl has been drained without start or boost pumps on.

(6) The engine has been shut down using the emergency fuel shutoff valve.

If a dual element fuel pump is installed, proceed to Fuel Control Purging.

Purge air from the single element pump filter bowl as follows:

WARNING: THE FUEL/AIR DISCHARGE DURING PURGING IS IRRITATING AND HIGHLY

FLAMMABLE. MECHANICS MUST TAKE SUITABLE MEASURES TO PROTECT

THEIR EYES AND TO PREVENT FIRE.

WARNING: ENSURE THAT THE AIRCRAFT IS ADEQUATELY GROUNDED. SEE AIRCRAFT

MANUFACTURER’S INSTRUCTIONS FOR PROPER GROUNDING

PROCEDURES.

(1) Remove lockwire from the upper drain plug in the filter bowl cover. (See FIG. 7, 9, 28 or

44.)

(a) Deactivate the ignition system.

(b) Turn on the aircraft boost pump.

shop towel to catch the spray. Retorque the plug to 40-65 lb in. (4.5-7.3 N^.m).

(d) Turn off the aircraft boost pump.

(e) Remove any fuel that may have spilled in the engine compartment.

(f)

Secure the drain plug with lockwire.

(g) Purge the fuel control. (Refer to Fuel Control Purging.)

38.

Fuel Control Purging

A. Maintenance of the fuel system can result in air entrapment in the fuel lines. To prevent

subsequent false starts or flameouts, purge air from the fuel system whenever any of the following

conditions are encountered:

WARNING: THE FUEL/AIR DISCHARGE DURING PURGING IS IRRITATING AND HIGHLY

FLAMMABLE. MECHANICS MUST TAKE SUITABLE MEASURES TO PROTECT

THEIR EYES AND PREVENT FIRE. ENSURE THAT THE AIRCRAFT IS ADEQUATELY

GROUNDED. (SEE AIRCRAFT MANUFACTURER’S INSTRUCTIONS FOR PROPER

GROUNDING PROCEDURES.

(1) Any of the conditions listed in from the Fuel System Air Purging are encountered.

(2) The fuel control is replaced.

(3) Any symptom indicative of air being entrapped in the system is observed.

39.

Fuel System Lines and Components Vacuum Check. (Bendix Fuel Control System)

NOTE: The vacuum check is a troubleshooting procedure to detect engine or airframe fuel system

leaks.

(This procedure is a troubleshooting tool and not a mandatory requirement).

A. The following vacuum check procedures are provided to check both the engine and airframe fuel

system components to try to isolate the location of a possible leak in the fuel system. (Refer to the

applicable airframe manual for additional information.)

NOTE: During the vacuum check procedures, it will be necessary to disconnect various fuel lines.

Prior to disconnecting any fuel line, verify that the coupling nuts and fitting were tightened

to the proper torque. If insufficient torque was applied, note how far the coupling nut or

fitting rotates to reach the proper torque. Inspect the connection areas for damage, or

indications of misalignment, overtightening, cracks, bends, grooves and fretting wear.

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(1)

Verify at the aircraft fuel tank that the fuel selector valve is in the closed position.

(2)

Remove the upper drain plug from the rear of the engine fuel pump filter housing. (If a Dual

Element Pump is installed, remove the fitting from the bottom of the filter bowl.) Check the

packing for damage. Connect a vacuum pump to the port. Ensure that the vacuum set-up

includes a negative pressure gage (in. Hg) and a shutoff valve between the gage and pump.

Apply 8 in. Hg vacuum and close the shutoff valve. Record gage reading after two minutes. If

vacuum loss exceeds 1/2 in. Hg after the two minutes, proceed to the next step. If vacuum

loss is 1/2 in. Hg or less, no further checks are required.

(3)

Disconnect the aircraft fuel line at the inlet to the engine fuel pump and cap the pump inlet

port. Repeat the vacuum leakage check. If vacuum loss exceeds 1/2 in. Hg, the leakage is in

the engine fuel system, proceed to the next step. If vacuum loss is 1/2 in. Hg or less, the

leakage is in the aircraft fuel supply system; proceed to step 1.

(4)

Disconnect the bypass fuel line between the engine fuel control and the fuel pump. Install

B-nut type caps on both the control and pump fittings. Repeat the vacuum leakage check. If

vacuum loss exceeds 1/2 in. Hg, proceed to next step. If vacuum loss is 1/2 in. Hg or less, the

leakage is in the bypass fuel line. Repair or replace parts as required, reassemble the engine

fuel system components and repeat step (3) to verify that the leak has been corrected.

(5)

Disconnect the pressure fuel line between the fuel pump and the fuel control. Install a B-nut

type cap on the fuel pump fitting. Repeat the vacuum leakage check. If vacuum loss exceeds

1/2 in. Hg, proceed to next step. If vacuum loss is 1/2 in. Hg or less, proceed to step (14).

(6)

Disconnect the impending filter bypass switch system at the AF and BF ports on the engine

fuel pump. Cap or plug both ports. Repeat the vacuum leakage checks. If vacuum loss

exceeds 1/2 in. Hg, proceed to next step. If vacuum loss is 1/2 in. Hg or less, the leakage is in

the filter bypass switch or its associated hoses. Refer to the applicable airframe manual and

repair as required. Reassemble the engine fuel system components and repeat step (3) to

verify that the leak has been corrected.

(7)

Inspect and check the two fuel bypass and pressure line fittings in the fuel pump and filter

assembly as follows:

(a) Remove the two fittings from the engine fuel pump and filter assembly.

(b) Inspect the packings for damage or cuts.

(d) Reinstall the two capped fittings with new packings.

(e) Repeat the vacuum leakage check. If vacuum loss exceeds 1/2 in. Hg, proceed to next

step. If vacuum leakage is less than 1/2 in. Hg, reassemble the engine fuel system

components and repeat step (3) to verify that the leak has been corrected.

(8)

Remove the lower drain valve on the rear of the engine fuel pump fuel filter housing. Inspect

the packing for damage. Also, inspect the valve stem packing for damage. Install a plug and

packing in the drain valve port and repeat the vacuum leakage check. If vacuum loss exceeds

1/2 in. Hg, proceed to next step. If vacuum loss is 1/2 in. Hg or less, the leakage is in the

drain valve and/or packings. Replace parts as required, reassemble the engine fuel system

components and repeat step (3) to verify that the leak has been corrected.

(9)

Inspect and check the engine fuel pump and filter assembly as follows:

(a) Ensure that the filter housing was securely attached to the pump. Remove the housing

and filter element. Inspect the large packing for damage or cuts. Inspect the packing

sealing surfaces for damage and repair as required. Inspect inside the filter housing and

pump housing for contamination and remove as required. Inspect the filter element (in

the fuel-wetted state) for contamination and replace if required.

Page 82

(b) Reassemble the filter element and housing on the pump using a new packing on the

housing.

(10) If vacuum loss exceeds 1/2 in. Hg, replace the fuel pump and filter assembly, reassemble the

engine fuel system components and repeat step (3) to verify that the leak has been corrected.

(11)

If vacuum loss is 1/2 in. Hg or less, reassemble the fuel system components and repeat step

(3) to verify that the leak has been corrected.

(12) Connect the vacuum pump to the control inlet fuel fitting on the fuel control. Repeat the

vacuum leakage check. If vacuum loss exceeds 1/2 in. Hg, proceed to the next step. If

vacuum loss is 1/2 in. Hg or less, repair or replace the pressure fuel line, reassemble the

engine fuel system components, and repeat step (3) to verify that the leak has been corrected.

(13) Inspect and check the two fuel bypass and pressure line fittings in the fuel control as follows:

(a) Remove the two fittings from the engine fuel control.

(b) Inspect the packings for damage or cuts.

(d) Reinstall the two fittings with new packings. Be sure the bypass fitting is capped and the

vacuum pump is reconnected to the pressure fitting.

(e) Repeat the vacuum leakage check.

(f)

If vacuum loss exceeds 1/2 in. Hg, replace the fuel control, reassemble the engine fuel

system components and repeat step (3) to verify that the leak has been corrected.

(g) If vacuum loss is 1/2 in. Hg or less, reassemble the engine fuel system components and

repeat step (3) to verify that the leak has been corrected.

(14) Connect the vacuum pump to the free end of the aircraft fuel line (the end that connects to the

engine fuel pump). Apply 8 in. Hg vacuum and close the shutoff valve. Record gage reading

after two minutes.

(a) If vacuum decreases, a leak in the aircraft fuel supply system is indicated. Check and

repair the leak in accordance with the applicable air-frame manual.

(b) If no leakage is detected, check the aircraft fuel line and the engine fuel pump inlet fitting.

Repair or replace parts as required. Reconnect the aircraft fuel line to the inlet port of the

engine fuel pump and filter assembly. Repeat step (3) to verify that the leak has been

corrected.

40.

Fuel System Purging

A. Perform fuel system purging as follows:

(1) Position a container under the aircraft to collect fuel drainage.

(2) Disconnect the fuel supply hose from the fuel nozzle. Be prepared to catch fuel from the fuel

hose.

(3) Deactivate the ignition system.

(4) Open the fire wall fuel valve.

(5) Turn on the boost pump(s)/start pump.

(6) Position the throttle to the 30° (Ground Idle) position.

(7) Motor the engine for approximately 15 sec or until there is no evidence of air coming from the

fuel supply hose.

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

FITTINGS AND TUBES COULD RESULT IN AN ENGINE FAILURE.

(8) Close the throttle and reconnect the fuel supply hose to the fuel nozzle. Torque the coupling

nut at the fuel nozzle to 80-120 lb in. (9.0-13.6 N^.m).

(9) Turn off the boost pump(s), and start pump(s). Reactivate the ignition system.

Page 83

41.

Fuel Leakage Inspection

A. If evidence of fuel leakage is found during postflight inspection of the fuel control, governor, fittings

and/or tubing, proceed as follows:

(1) Isolate the source of leakage by immediately applying boost pump pressure to the system.

Fuel leakage shall be limited to the following specific areas and quantities:

Max Leakage Rate

Unit or Area

Drops/min

cc/min

Seal drain fuel pump

0.25

Splitlines, tubes, and fittings

None

(2) If the fuel leak cannot be isolated using only boost pump pressure, make an engine start; then,

carefully reinspect the engine compartment with the engine running. If necessary, reinspect

immediately upon engine shutdown.

(3) Repair fuel leak as follows:

(a) Tighten all component fittings and coupling nuts to the recommended torque. If leakage

does not stop after tightening the fitting or coupling nut to recommended torque, replace

the affected part.

(b) After leakage repair has been accomplished, recheck the fuel system under boost pump

pressure.

42.

Fuel Control System Pneumatic Leak Check

If any fuel system component (including piping) is removed/installed or any line is opened during

maintenance of the control system, inspect the pneumatic portion of the fuel control system for

leaks as follows:

(1)

Disconnect and remove the pressure sensing line between the scroll and the P_c filter. Hold the

filter while loosening the coupling nut.

(2)

Move the throttle to the full open position.

(3)

Apply 50-80 psi (345-552 kPa) filtered air (10 micron) to the P_c filter. Air will immediately

escape from the pressure regulating air valve port on the power turbine governor.

(4)

Use a liquid soap solution to check all fittings and lines in the system for leaks. Leakage is not

acceptable on fittings and lines.

(5)

Use a liquid soap solution to check the air tubes for leakage. Cover and parting surfaces on

the fuel control and governor which produce a slight bubbling of the soap solution do not

represent a leak of sufficient magnitude to warrant concern. These leaks were present during

original calibration and were compensated for at that time.

(6)

Reduce the pressure to 20-22 psi (138-152 kPa) and check the governor diaphragm for

leakage. No leakage is acceptable. If leakage is noted from the governor diaphragm, remove

the safety wire from the screws, back off screws and then torque to 8-11 lb in. (0.9-1.2 N^.m).

Let screws rest for 20 minutes and retorque to same value. If after this is completed, the

governor diaphragm still leaks, replace governor.

(7)

Return throttle to the closed position. Clean the soap solution from the engine after the check

is completed.

(8)

Reinstall P_c line. Torque coupling nuts to 80-120 lb in. (9.0-13.6 N@m). Hold Pc filter while

torquing coupling nut.

Page 84

43.

Fuel System Filter Maintenance

A. The filters which are maintained as a part of the engine assembly fuel system include: a fuel pump

fuel filter, a gas producer fuel control inlet strainer, and a fuel nozzle strainer.

B. In addition to the fuel filters, the Bendix control system has a fuel control P_c air filter and an engine

(system) P_c filter which is bracket mounted to the gearbox.

CAUTION: WHEN THERE IS EVIDENCE THAT THE FUEL PUMP FILTER HAS BEEN BYPASSED,

THE GAS PRODUCER FUEL CONTROL INLET STRAINER AND THE FUEL NOZZLE

STRAINER MUST BE CLEANED. (REFER TO SPECIAL INSPECTIONS, TABLE 9,

ITEMS 14 AF, AG, AND AK FOR DETAILS.)

(1) Fuel Pump Filter. The fuel pump filter element is replaceable and has a 5 micron nominal/15

micron absolute rating. Replace the filter at intervals specified in Scheduled Inspections, Table

8, unless an aircraft installed differential pressure warning system and/or operating experience

dictate replacement at a lesser time interval.

(2) Gas Producer Fuel Control Strainer. The strainer element in the fuel control is cleanable and

has a rating of 45 microns. The filter shall be inspected for contamination and cleaned if

required any time a fuel pump filter bypass is known or suspected to have taken place. (Refer

to Cleaning the Gas Producer Fuel Control Fuel Strainer.)

(3) Fuel Nozzle Strainer. The fuel nozzle strainer should only be inspected and cleaned if a fuel

filter bypass condition is known or suspected. (Refer to Fuel Nozzle Maintenance.)

(4) Fuel Control P_c Filter. The fuel control P_c filter shall be removed and cleaned when dictated by

engine performance. Clean the fuel control pneumatic system. Refer to Gas Producer Fuel

Control Air Circuit Cleaning.

(5) Engine (system) P_c Filter. The bracket mounted P_c filter shall be removed and cleaned when

dictated by engine performance. (Refer to Table 6- and P_c Filter Maintenance.)

C. Replace the filter in a dual element fuel pump as follows: (Ref. FIG. 6)

CAUTION: FILTER ELEMENT IS A THROW-AWAY AND IS NOT TO BE CLEANED AND REUSED.

(1) Cut the lockwire and loosen the cover by turning the one inch hex. Position a container under

the pump assembly as some fuel spillage is likely.

(2) Remove the cover and the element. Discard two O-rings and the contaminated filter element.

If the element is a tight fit, remove by pulling straight out. Twisting may cause the element end

cap to tear off.

(3) Clean the filter cap with a spray of mineral spirits or with a fuel-soaked cloth.

(4) Replace O-ring seal on filter element. Reinstall the filter in reverse of the order of removal.

Replace the O-ring seal between the cover and housing. Torque the cover to 180-220 lb in.

(20-25 N^.m) and secure with 0.032 in. (0.813 mm) lockwire.

(5) Purge air from the fuel system. (Refer to Fuel System Air Purging.)

D. Replace the filter in a single element fuel pump as follows: (Ref. FIG. 7)

CAUTION: THIS IS A THROW-AWAY FILTER ELEMENT AND IS NOT TO BE CLEANED AND

REUSED.

(1) Place a container under the pump assembly as some fuel spillage is likely. Remove the two

screws and washers retaining the cover to the housing.

(2) Remove the cover and the element. Discard two O-rings and the contaminated filter element.

If the element is a tight fit, remove by pulling straight out. Twisting may cause the element end

cap to tear off.

Page 85

(3) Clean the filter cap with a spray of mineral spirits or with a fuel-soaked cloth.

(4) Be sure the element O-ring is in place then install the element in the housing. Install the cover

with new O-ring. Torque cover screws to 95-105 lb in. (10.7-11.8 N^.m).

(5) Purge air from the fuel system. (Refer to Fuel System Air Purging)

44.

Fuel Nozzle Maintenance

Perform maintenance to the fuel nozzle as follows: (See FIG. 8, 9, or 10)

CAUTION: PARTICULAR CARE MUST BE TAKEN DURING REMOVAL NOT TO DAMAGE THE

NOZZLE SPRAY TIPS.

A. Remove the fuel nozzle as follows:

(1) Remove lockwire and disconnect the fuel nozzle line.

(2) Remove lockwire; then using 23002215 wrench, unscrew the nozzle.

(3) Carefully remove nozzle assembly.

B. Inspect and clean the fuel nozzle as follows:

(1) Check for damage or carbon deposits on spray tips. FIG. 11 shows the condition of a typical

fuel nozzle removed from an operational engine. A nozzle in this condition should be cleaned,

if possible, before being reinstalled.

CAUTION: USE EXTREME CARE NOT TO DAMAGE THE MIRROR FINISH AND EDGES OF

THE SPRAY TIPS DURING THE CLEANING OPERATION.

NOTE: Removal of external carbon deposits from the fuel nozzle spray tip can correct a

streaking problem. Therefore, cleaning the spray tip may make it unnecessary to

disassemble the fuel nozzle.

Carbon Buildup on Fuel Nozzle

FIG. 11

(2) Suspend the fuel nozzle vertically with the tip immersed approximately 1/8 in. (3 mm) in

cleaning solvent (Brulin Safety Solvent No. 512 M or equivalent). Soak the tip for one hour, or

longer if deemed necessary, to remove all carbon. Use a soft bristle nylon brush, such as a

tooth brush, to remove any remaining carbon buildup from the nozzle tip. Be careful that

loosened carbon does not enter the spray tip.

CAUTION: DO NOT USE COMPRESSED AIR TO DRY NOZZLE. THIS CAN DAMAGE THE

NOZZLE.

(3) After carbon removal, flush the nozzle internally and externally using Stoddard solvent or

kerosene. Dry with a soft cloth.

Page 90

(4) Any damage to the nozzle spray tips is cause for replacement of the fuel nozzle assembly.

(5) Reject nozzles exceeding 0.005 in. (0.127 mm) max. wear on OD of the outer air shroud.

(6) Clean the face of the outer air shroud with a clean dry cloth; the air holes must be open. Be

careful that loosened carbon does not enter the spray tips.

Inspect and clean the fuel nozzle as follows: (Alternate Procedure)

(1) Check for damage or carbon deposits on spray tips. FIG. 11 shows the condition of a typical

fuel nozzle removed from an operational engine. A nozzle in this condition should be cleaned,

if possible, before being reinstalled.

CAUTION: USE EXTREME CARE NOT TO DAMAGE THE MIRROR FINISH AND EDGES OF

THE SPRAY TIPS DURING THE CLEANING OPERATION.

(2) Suspend the nozzle vertically with the tip immersed approximately 1/8 in. (3 mm) in Brulin 815

QR (or equivalent). Heating the solvent to 140_ F (60_ C) is optional. Approximately 8 hours

is a desired soak time. All carbon should be removed or loosened after this process. Use a

soft bristle nylon brush, such as a tooth brush, to remove any remaining carbon buildup from

the nozzle tip. Be careful that loosened carbon does not enter the spray tip.

CAUTION: DO NOT USE COMPRESSED AIR TO DRY NOZZLE. THIS CAN DAMAGE THE

NOZZLE.

(3) After carbon removal, flush the nozzle internally and externally using Stoddard solvent or

kerosene. Dry with a soft cloth.

(4) If carbon is still visible, soak nozzle tip in Turco 4181 (or equivalent) at 140_ F (60_ C) for two

hours. Flush nozzle thoroughly with hot water then Stoddard solvent or kerosene. Dry with a

soft cloth.

(5) If the nozzle is still streaking, carbon is probably not the issue. Send the nozzle to an

authorized facility for further inspection.

(6) Any damage to the nozzle spray tips is cause for replacement of the fuel nozzle assembly.

(7) Reject nozzles exceeding 0.005 in. (0.127 mm) max. wear on OD of the outer air shroud.

(8) Clean the face of the outer air shroud with a clean dry cloth; the air holes must be open. Be

careful that loosened carbon does not enter the spray tips.

Disassemble the fuel nozzle as follows: (See FIG. 12)

CAUTION: USE EXTREME CARE TO PREVENT DAMAGE TO THE MIRROR FINISH AND

EDGES OF THE SPRAY TIP. THE NOZZLE SHOULD BE DISASSEMBLED IN A

CLEAN AREA AND CARE SHOULD BE TAKEN TO AVOID DIRT OR OTHER

CONTAMINATION.

(1) Note the position of the lockwire on the fuel nozzle; then remove the lockwire.

(2) Count the number of visible threads on the outer air shroud. Retain this number for verification

that the fuel nozzle has been correctly assembled.

CAUTION: IF A 6897875 FIXTURE IS NOT AVAILABLE, THE WRENCHING SURFACES OF

THE BODY MAY BE HELD IN A VISE. DO NOT OVER TIGHTEN THE VISE AND

USE CARE TO PREVENT DAMAGE TO THE NOZZLE ASSEMBLY.

(3) Insert the fuel nozzle body in 6897875 holding fixture. Unscrew the outer air shroud.

(4) Carefully remove the spray tip assembly from the outer air shroud and the filter from the body.

No further disassembly is permitted.

Page 91

Inspect the disassembled fuel nozzle for signs of contamination and serviceability. Return the

entire fuel nozzle to an Authorized Maintenance Center or Repair Facility if any of the following

conditions are found:

NOTE: Minor contamination may be removed by agitating the filter assembly in clean Stoddard

Solvent or Kerosene. Air dry and inspect after cleaning.

(1) Contamination covering more than 50% of the filter assembly.

(2) Tears or cracks in the filter assembly.

(3) Collapsed screen in the filter assembly.

(4) Obvious contamination or damage to other portions of the fuel nozzle assembly.

(5) The nozzle has been inadvertently disassembled further than allowed.

Reassemble the fuel nozzle as follows:

(1) Hold the body in a vertical position and insert the filter assembly.

(2) Place the spray tip assembly in the body. Be sure it is properly engaged with the filter.

NOTE: Be sure that the filter assembly remains seated on the spray tip assembly.

(3) Retain the nozzle in a vertical position. Screw the outer air shroud onto the body.

(4) Verify that the nozzle has been correctly assembled by counting the number of visible threads

on the outer air shroud. (Refer to para C.(2))

CAUTION: IF A 6897875 FIXTURE IS NOT AVAILABLE, THE WRENCHING SURFACES OF

THE BODY MAY BE HELD IN A VISE. DO NOT OVER TIGHTEN THE VISE AND

USE CARE TO PREVENT DAMAGE TO THE NOZZLE ASSEMBLY.

(5) Insert the fuel nozzle in holding fixture 6897875 or a vise and tighten the outer air shroud to

25-30 lb ft (34-41 N^.m) and secure with 0.020 in. (0.051 mm) lockwire.

1. Fuel Nozzle Body

3. Spray Tip Assembly

2. Filter Assembly

4. Outer Air Shroud

Fuel Nozzle Assembly

FIG. 12

Page 92

G. Install the fuel nozzle as follows:

(1) Install in reverse order of removal.

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

FITTINGS AND TUBES COULD RESULT IN AN ENGINE FAILURE.

(2) When replacing and/or reinstalling the fuel nozzle, apply a light coat of antiseize compound

(NS-165) to the threads. Torque nozzle to 200-300 lb in. (23-34 N^.m) using 23007638

wrench. Lockwire to spark igniter. Torque line coupling to 80-120 lb in. (9.0-13.6 N^.m).

Lockwire fuel hose.

(3) Check run the engine after fuel nozzle replacement. (Refer to Engine Check Run Operating

Instructions.)

45.

P_c Filter Maintenance.

NOTE: The P_c filter may be directly mounted in the P_c port in the compressor scroll or it may be

bracket mounted to the gearbox. If the filter is scroll mounted, disregard sub para (1) and

(3).

Remove the P_c filter as follows: (See Figure 10)

(1) Remove the Scroll-to-Pc Filter Tube Assy by disconnecting the line at both ends. Hold the

filter assembly by placing the proper size wrench on the large hex flats of the housing or filter

element while loosening the coupling nut.

(2) Disconnect the Pc air tube from the aft end of the filter. Hold the filter assembly as outlined

above while loosening the coupling nut.

WARNING: FAILURE TO PROPERLY REMOVE OR INSTALL P_C AIR TUBES MAY DAMAGE

TUBES, FITTINGS, AND/OR THE FILTER ASSEMBLY WHICH CAN RESULT IN

SUDDEN UNINTENDED ENGINE POWER LOSS.

(3) Remove the nut and bolt securing the filter clamp to filter mounting bracket. Remove the filter

and separate the clamp from the filter.

(4) Remove the P_c filter. Discard the O-ring if P_c filter is scroll mounted.

(5) Remove the lockwire and separate the filter element and O-ring from the filter housing. (See

Figure 13) When a vise is used, place the element hex (1, Figure 13) in the vise and use the

wrench on the hex of the housing (3).

Clean the filter assembly ultrasonically if equipment is available. If ultrasonic equipment is not

available, use either alternate cleaning method as follows:

(1) Solvent and brush method.

(a) Cap the outlet fitting of the element with a clean metal cap (AN820-4 or equivalent).

(b) Wash the element with solvent and a soft bristle brush.

(689-827 kPa), in a reverse flow direction (through the outlet fitting).

(2) Sodium hydroxide soak method.

WARNING: SODIUM HYDROXIDE CAN CAUSE SEVERE BURNS. DO NOT GET IN

EYES, ON SKIN OR ON CLOTHING. IN THE EVENT OF CONTACT WITH

SODIUM HYDROXIDE, IMMEDIATELY FLOOD EXPOSED SKIN OR

CLOTHING WITH WATER. FOR EYES, FLUSH HEAVILY WITH WATER AND

OBTAIN IMMEDIATE MEDICAL ATTENTION.

WARNING: POTASSIUM PERMANGANATE CAN BE VERY DANGEROUS IF

IMPROPERLY HANDLED. CONTACT WITH ORGANIC MATERIALS (OIL,

GREASE) CAN CAUSE FIRE.

(a) Soak the filter element in a sodium hydroxide solution at 102-107°C (215-225°F) for a

maximum of one hour.

Page 93

Inspect the filter assembly for dirt or damage as follows:

NOTE: Replace unserviceable filters.

Assemble the filter assembly as follows:

(1)

Apply high temperature lubricant (Never-Seez or equivalent) lightly to the threads. Assemble

the packing and the housing over the filter element. If a metallic O-ring is used, Torque to

60-65 lb ft (81-88 N^.m) and secure with lockwire. If a rubber O-ring is used, Torque to 60-65

lb in. (6.8-7.3 N^.m) and secure with lockwire.

(2)

Install the P_c filter.

(a) On gearbox mounted P_c filter configurations, assemble the clamp on the filter and secure

it to the filter mounting bracket with a bolt and nut. Torque nut to 35-40 lb in. (3.9-4.5

N^.m). Check to assure filter arrow is pointing rearward.

CAUTION: ENSURE THAT ROLLS-ROYCE COMMERCIAL ENGINE BULLETIN 250-C18

CEB-142 HAS BEEN ACCOMPLISHED (RELOCATION OF P_C FILTER).

MANDATORY COMPLIANCE DATE FOR 250-C18 CEB-142 WAS OCTOBER

15, 1978.

(b) On scroll mounted P_c filter configurations, mask the filter body and probe of the P_c filter.

Apply a very light, even coat of bonded lubricant to the threads of the probe end of the

filter (Electrofilm LubriBond A Resin, Molybdenum Disulfide Solid Film Lubricant or

equivalent). Allow the lubricant a minimum of 30 minutes to air dry. Install the P_c filter

with a new O-ring in the compressor scroll. Torque the filter to 75-85 lb in. (8.5-9.6 N^.m).

WARNING: FAILURE TO PROPERLY REMOVE OR INSTALL PC AIR LINES MAY

DAMAGE LINES, FITTINGS, AND/OR FILTER ASSEMBLY WHICH CAN

RESULT IN SUDDEN UNINTENDED ENGINE POWER LOSS.

Attach the Scroll-to-P_c Filter Tube Assembly to the compressor scroll. Torque

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

Attach the Scroll-to-P_c Filter Tube Assembly to the forward end of the P_c Filter.

Attach the P_c Filter-to-Governor Tube Assembly to the aft end of the filter. Hold the

filter with the proper wrench at the hex flats of the filter assembly, while tightening the

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

Perform a leak check of the pneumatic system following installation of the P_c Filter. (Refer to Fuel

Control System Pneumatic Leak Check.)

46.

Gas Producer Fuel Control Maintenance. (Ref. FIG. 14)

The gas producer fuel control can be adjusted, the control fuel filter can be cleaned, or the control

assembly can be replaced as dictated by the engine trouble condition encountered.

NOTE: Refer to Fuel Control Operational Checks for a ready method of ground checking the control

system and associated linkage.

A. Fuel Control Adjustments

(1) The adjustments that can be made on the fuel control are idle speed, maximum speed and

start derichment. (The start derichment adjustment is not on all configurations.) Also, on

6899260 (Bendix 2524527-9) or later fuel controls, there is a start/acceleration fuel flow

schedule adjustment and a wide range start derichment adjustment.

Page 95

1. Control Inlet Fuel (P₁)

5. Regulated Air Pressure (P_r)

2. Metered Fuel Flow (P₂)

6. Governing Pressure (Pg)

3. Control Bypass (P_o)

7. Gas Producer Lever

4. Sensing Pressure (P_c)

8. Overspeed Bleed (P_y)

Gas Producer Fuel Control

FIG. 14

Idle Setting. Refer to Fuel Control Operational Checks.

Maximum Speed Stop.(Ref. FIG. 15)

CAUTION: DO NOT ADJUST MAXIMUM SPEED STOP IF 749°C (1380°F) TOT CAN BE

REACHED. DO NOT EXCEED 104% N₁.

NOTE: Maximum speed adjustment is not a periodic adjustment. It should be made only

when absolutely required. In situations where N₁ speed peaks below the stated limit

and TOT is below the maximum limit, resulting in a low power condition, maximum

speed adjustment may restore specified performance. DO NOT adjust more than

one turn at a time. Operate the engine after each adjustment to confirm the results.

(1) Adjust screw clockwise to increase or counterclockwise to decrease N₁ speed. One turn

equals approximately 1% speed.

Engine Starting Characteristic Adjustments

There are two fuel control adjustments which can be used to change the starting characteristic of

the engine. These adjustments are a Start-Derichment Adjustment in addition to a

Start/Acceleration Adjustment which is on Fuel Controls P/N 6899260 or later. (Ref. FIG. 15) The

conditions which can be improved by these adjustments are given in Table 10. Correct these

conditions using the stated recommended adjustment(s).

Page 96

Gas Producer Fuel Control Adjustments

FIG. 15

TABLE 10

Adjustments to Improve Starting

Conditions

Recommended Adjustments

Excessive lightoff temperature - N1 speed below

Adjust start/acceleration ccw. If any additional

20% and over 810° C (1490°F) with a momentary

correction is necessary, adjust start-derichment ccw.

peak of one second max at 927°C (1700°) (for a pe-

(Refer to paragraphs E and F for procedures.)

riod not to exceed 10 seconds.

Low lightoff temperature - N₁ speed below 20% and

Adjust start/acceleration cw.

(Refer to paragraph F.

slow acceleration with lightoff temperature below

for procedure.)

550°C (1022°F)

High rapid temperature rise with N1 speed at

Adjust start-derichment ccw. If any additional

25-30%. (Refer to paragraphs E and F for proce-

correction is necessary adjust start/acceleration ccw.

dures.)

(Refer to paragraphs E and F for procedures. )

Low lightoff temperature with slow start - N1 speed

Adjust start-derichment cw. If additional correction

hesitation at 20-33% and lightoff temperature below

is necessary, adjust start/acceleration cw. (Refer to

approx 550°C (1022°F) with starting time approach-

paragraphs E and F for procedures.)

ing 60 seconds (or more).

High lightoff temperature - N1 speed at 35-55% and

Adjust start/acceleration ccw.

(Refer to paragraph F.

over 180°C (1490°F) with a momentary peak of one

for procedure.)

second max at 927°C (1700°F) for a period not to

exceed 10 seconds.

Low lightoff temperature with slow-to-hung starts -

Adjust start/acceleration cw.

(Refer to paragraph F.

N1 speed hesitation at 35-55% and lightoff tempera-

for procedure.)

ture below approx 550°C (1022°F) with starting time

approaching 60 seconds (or more).

Page 97

Start/Acceleration and Start-Derichment Adjustments

FIG. 16

E. Start-Derichment Adjustment. (Ref. FIG. 15 or 16) The start-derichment (derich) adjustment can

be used to correct lean (slow) start or rich (hot) start conditions. This adjustment is effective below

33% N1 speed. For slow starts at N1 speeds between 35 and 55% N1 speed, refer to

Start/Acceleration Fuel Flow Adjustment, para F. (Refer to Table 10.)

NOTE: The start derichment adjustment on the 6899260 (or later) fuel control has a wider angular

range than earlier models (200 degrees in place of 100 degrees). Neutral position for the

6899260 control is 7 dots/70° from the ccw stop. Neutral on controls prior to 6899262 is

4 dots/40° ccw. The effective start derichment speed range is between 20 and 33% N1.

Also, turning the adjustment to the cw stop closes the P_y vent which deactivates the start

derichment adjustment.

NOTE: To accurately determine the proper adjustment, conditions under which the adjustments

are made should be consistent i.e., a fully charged aircraft battery, the same residual TOT

and the same lightoff speed.

(1) For low temperature with slow starts at 20-33% N1 speed, adjust the start-derichment as

follows:

(a) Remove the lockwire securing the adjustment locknut to the P_c filter-fitting.

Page 98

CAUTION: DO NOT DISTURB THE POINTER-TO-SHAFT SEALED WIRE AT ANY TIME.

THIS IS AN OVERHAUL FUNCTION ONLY.

(b) Loosen the adjustment locknut.

CAUTION: DURING THE ATTEMPTED START, TOT MUST BE CLOSELY MONITORED

TO PREVENT OVERTEMPERATURE OPERATION. RECORD

OVERTEMPERATURE IN THE ENGINE LOG.

flow to improve stagnated starts, cold weather starts, or high altitude ground starts. Make

the adjustment in 15° maximum increments (dots are 10° apart) and tighten the locknut to

20-25 lb in. (2.3-2.8 N^.m) after each setting. Check the starting peak TOT after each

setting until satisfactory starts are made.

(d) When the desired adjustment is obtained, secure the locknut to the P_c filter-fitting with

lockwire.

CAUTION: MONITOR TOT CLOSELY AFTER START-DERICHMENT ADJUSTMENT TO

BE SURE OVERTEMPERATURE LIMITS ARE NOT EXCEEDED.

(e)

On fuel controls prior to P/N 6899260 (Bendix P/L 2524527-9), if satisfactory starts are

not obtained during steps (a) through (d), proceed as follows:

Return the start-derich pointer to the neutral position. Torque locknut.

Install a short No. 10-32 screw into the vent fitting on the start-derich cover. This

deactivates the start-derich assembly and allows the operator to check the basic fuel

schedule of the control.

Enrich the basic schedule slightly by retighten the start-derich cover screws.

Remove lockwire from the screws, then check screw retention torque. Torque

should be 9-10 lb in. (1.02-1.13 N^.m). Retighten the screws in 2 lb in. (0.23 N^.m)

increments to a maximum value of 14 lb in. (1.69 N^.m). After each 2 lb in. (0.23 N^.m)

retightening operation, make a start attempt. It is not necessary to remove the No.

10-32 screw from the vent at this time; this is only a check of the integrity of the

basic schedule. If satisfactory starts are obtained, lockwire the derich assembly

cover screws and remove the No. 10-32 screw from the vent fitting. Make another

start. It may be necessary to adjust the start-derich assembly from the neutral

position. After final adjustments have been made, lockwire the start-derich

assembly.

(f)

On fuel controls prior to P/N 6899260 (Bendix P/L 2524527-9), if satisfactory starts are

not obtained during steps (a) through (e), proceed as follows:

Return the pointer to the neutral position (4 dots/40° from the ccw stop).

Disconnect the fuel control-to-inline check valve tube. Provide a means of directing

fuel that will be discharged from this port on the control into a clean container.

Deactivate primary power to the ignition system.

Motor the engine to approximately 15% N1 speed; then open the throttle to the 30°

(Ground Idle) position. Motor the engine for 15 seconds; then close the throttle.

NOTE: This procedure is based upon a 15 second fuel flow. Be sure the throttle is

closed exactly 15 seconds after it is opened.

Using a calibrated beaker, measure the quantity of fuel in the container. There

should be 85-95 cc of fuel in the beaker at sea level. At higher altitudes the flow will

be less.

NOTE: For improved accuracy, take the average of three readings.

Enrich the basic schedule by adding one shim under the metering valve sleeve

retainer.

(Ref. FIG. 17.) Select the shim to give the desired fuel flow schedule. The

approximate fuel flow gain for each shim thickness is as follows:

Page 99

Shim Thickness,

Fuel Flow

Temp Increase,

in.

Gain, cc

°C

°F

0.001

0.025

162

0.0015

0.0381

140

252

0.002

0.051

180

324

0.003

0.076

240

432

NOTE: Only one size shim may be used. Maximum shim thickness must not exceed 0.003

in. (0.076 mm).

Cut out the selected size shim using the template shown in FIG. 17.

Clean up all burrs.

NOTE: A kit (Bendix P/N 350934) containing one each of the 0.001, 0.0015, 0.002

and 0.003 in. (0.025, 0.0381, 0.051 and 0.076 mm) shims is available

through Bendix Supply Centers.

Remove lockwire and loosen screws securing the metering valve sleeve retainer.

Loosen screws enough to allow insertion of the shim under the retainer. Insert

selected shim and Torque screws to 9-10 lb in. (1.02-1.13 N^.m).

(g) Recheck the fuel flow setting as was accomplished in steps (a) through (e).

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

FITTINGS AND TUBES COULD RESULT IN AN ENGINE FAILURE.

(h) If the desired fuel flow is obtained, reinstall the fuel control-to-inline check valve tube.

Torque coupling nuts to 80-120 lb in. (9.0-13.6 N^.m).

CAUTION: DURING A START ATTEMPT, TOT MUST BE CLOSELY MONITORED TO

PREVENT OVERTEMPERATURE OPERATION. RECORD OVER-

TEMPERATURE IN THE ENGINE LOG.

(i)

Start the engine. If satisfactory starts are obtained, lockwire the screws on the metering

valve sleeve retainer. It may be necessary to adjust the start-derich assembly from the

neutral position. After final adjustments have been made, lockwire the start-derich

assembly.

Inspect to determine that there is no obstruction in the vent hole in the start-derich

cover.

(2)

Rich (hot) starts may be caused by delayed ignition, or premature opening of the throttle.

However, hot starts due to high fuel flow are normally caused by the fuel control. When the

fuel control is suspected, make an adjustment of the start-derich setting as follows:

(a) Remove lockwire and loosen the adjustment locknut (Ref. FIG. 16).

(b) Make the adjustment using an Allen wrench. Turn counterclockwise (ccw) to lean-out the

fuel flow. Make the adjustment in 15° maximum decrements (dots are 10° apart) and

Torque the locknut after each setting. Check the starting peak TOT after each setting

until satisfactory starts are made.

lockwire.

(d) On fuel controls prior to P/N 6899260 (Bendix P/L 2524527-9), if satisfactory starts are

not obtained during steps (a) through (c), return the pointer to the neutral position (4

dots/40° from the ccw stop) and proceed as follows:

Page 100

CAUTION: DURING THE ATTEMPTED START, TOT MUST BE CLOSELY

MONITORED TO PREVENT OVERTEMPERATURE OPERATION.

RECORD OVERTEMPERATURE IN THE ENGINE LOG.

Check the basic fuel schedule by monitoring the first TOT indication. TOT should

not exceed 860° C (1580°F). If TOT is between 860°C (1580°F) and 927°C

(1700°F), derich the basic schedule slightly by retighten the start-derich cover

screws. Remove the lockwire from the screws; then check the screw retention

torque. Torque should be 9-10 lb in. (1.02-1.13 N^.m). Retighten the screws to the

minimum value of 9 lb in. (1.02 N^.m). Attempt another start. TOT must not exceed

860°C (1580°F). If satisfactory starts are obtained, lockwire the derich assembly

cover screws and the start-derich assembly. If decreasing the cover assembly

screw torque does not bring start TOT down to the 860°C (1580°F) limit, the fuel

control must be removed and recalibrated.

Start/Acceleration Fuel Flow Adjustment (Applicable to 6899260, Bendix 2524527-9, or later fuel

controls). The start/acceleration fuel flow schedule adjustment maintains the gas producer fuel

control starting schedule within acceptable limits during normal service life.

(1) To optimize engine starting, the start-derichment adjustment should be made in conjunction

with the start/acceleration adjustment. (Refer to Table 10.)

CAUTION: DO NOT USE THE START/ACCELERATION ADJUSTMENT TO CORRECT FOR

NORMAL MAINTENANCE ITEMS SUCH AS MIS-RIGGING, AIR LEAKS, FUEL

LEAKS, FAULTY FUEL NOZZLE, IGNITION PROBLEMS, STARTER-GENERATOR

SYSTEM PROBLEMS ETC. DO NOT USE THE START/ACCELERATION

ADJUSTMENT EXCLUSIVELY TO IMPROVE ENGINE STARTING. EXCESSIVE

CW SETTINGS BEFORE ENCOUNTERING OVERTEMPERATURE RESULTS IN A

SINGLE HIGH PEAK TOT OVER A WIDE SPEED RANGE FOR A LARGE PART

OF THE STARTING TIME. USE THE START-DERICH ADJUSTMENT WITH THE

START/ACCELERATION ADJUSTMENT TO OPTIMIZE ENGINE STARTING.

(2)

Remove lockwire and make the start-acceleration fuel flow adjustment as follows:

NOTE: To accurately determine the proper adjustment, conditions under which the

adjustments are made should be consistent, i.e., a fully charged aircraft battery, the

same residual TOT and the same lightoff speed.

NOTE: There are eight positions for the adjuster (the neutral position is three clicks from the

ccw stop). Detent grooves hold the adjuster in the selected one of these positions

without the need of a jam nut.

NOTE: A required adjustment of more than two clicks cw is an indication that the fuel control

is not the cause of the problem.

(a) For low lightoff temperature or slow/hung starts, turn the adjuster cw. Make the

adjustment in changes of one detent (click) at a time.

CAUTION: AN OVER ADJUSTMENT OF THE START/ACCELERATION CW

SETTING CAN CAUSE OVERTEMPERATURE STARTS OR

COMPRESSOR SURGE.

(b) If the adjuster is positioned to the full clockwise stop and low lightoff temperatures or

slow/hung starts are still encountered,perform as follows:

Ensure there are no pneumatic leaks. (Refer to Fuel System Pneumatic Leak

Check.)

Shim the fuel control metering valve sleeve. (Refer to para E (3) for details.)

changes of one detent (click) at a time.

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Rolls-Royce Engine 250–C18, 250–C18A, 250–C18B, 250–C18C. Operation and Maintenance Manual (2003) - page 6