Apu55 131-9b Appendix - Final

Appendix APU131-9B

Presenter

2011 Honeywell Air Transport Operators Conference

Honeywell Proprietary

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Appendix- APU131-9B, P/N 3800702-1

• Maintenance and Troubleshooting

– Condition monitoring

– No APU bleed air

– APU no-start with fault 49-41010

– No bleed air or generator after landing

– Load shed and speed droop

– APU on-wing vibration measurement

– Fuel manifold conical seals

– Safety wire chafing on fuel manifold

• Past Subjects / Closed

– Eductor Erosion

– Temporary Repair for Diffuser Housing Studs Pulled Out

– Real Time Oil Level


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Maintenance and Troubleshooting

• 131-9B APU Condition Monitoring Available

– Some operators using this method of APU trend monitoring until

PTMD is available.

– Uses Cockpit Display Unit (CDU) to access CT5ATP

• CT5ATP is T5 corrected for outside temperature, pressure, generator load

and IGV position

– Boeing Fleet Team Digest Article (737NG-FTD-49-04005) provides

method and parameters

• Check CT5ATP at 45-90 day intervals

• At 638C/1180F, reduce interval by 25% to 50%

• At 653C/1207F, schedule APU for removal within next 200 hours

Values and Intervals Will Vary Based on Operator Requirements


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– Eductor Erosion




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• Issue


• Background

– APU started and ran but no bleed air

• Maint Codes 49-52102, 49-52273 and 49-52303

• Findings

– Corroded splice in P/N 3888449-1 APU wiring

– Splice located on the bottom of the APU wrapped

with heat shrink

• Corrective Action

– Replace with P/N M81824-1-3 environmental splice

using manual 49-11-01


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– Eductor Erosion




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• Issue


• Background

– APU lights off but will not accelerate.

• Usually after a long flight and cold soak

• Findings

– Operators have found that fault 49-41010 coupled with high time on

power section is most likely caused by a worn power section

• Corrective Action/ Recommendation

– If the APU demonstrates no starts after cold soak and fault 49-41010,

check the CT5ATP value in the CDU / APU DMM

• If the value is above 653C/1207F, do not troubleshoot further, schedule

the APU for replacement

• If the value is below 653C/1207F, follow instructions in Aircraft FIM.

– See Condition Monitoring


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– Eductor Erosion




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• Issue


• Background

– Hydraulic lock holds SOV blade closed

• Prevents secondary fuel flow

– Low fuel flow causes speed droop

• Speed droop disables generator and bleed air

• ECU commands more fuel then resolver in

FCU measures less than command.

– Fault 49-31171 / „Fuel Flow Disagrees With

Command‟

• Corrective action

– Shut down APU, allow hydraulic lock to

dissipate and re-start APU.

– LRU replacement WILL NOT resolve this

issue.

Prim

ary

fue

l flow

Se

co

nd

ary

fue

l flow

Flow Divider SOV


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– Eductor Erosion




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• Issue


• Background

– Started in-flight and gradually got worse

– Troubleshooting took six weeks

– Maintenance messages 49-11019, 49-31016, 49-41010

– Troubleshooting included

• Continuity test from APU

• Generator replaced

• FCU replaced

• IGV test was carried ou

• Surge Control Valve replaced

• ECU replaced

• IGV replaced

• SCU replaced

• Inlet Pressure Sensor replaced

• Total Pressure Sensor replaced

• Differential Pressure Sensor replaced

• Fuel Flow Divider Solenoid replaced


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• Findings

– Plastic in the inlet found after APU

was removed

– Bag was removed and the APU was

re-installed into the A/C with no

further problems

• Recommendation

– Be aware of the close proximity

between the APU inlet and the R/H

aft cabin door

– When checking the inlet for

obstructions, check the whole inlet

– From the A/C skin all the way down

to the APU . . . carefully


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– Eductor Erosion




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131-9B APU Vibration Survey Program

• Issue

– Operator has requested Honeywell develop an

On-Wing Vibration Survey Capability

• Background

– Two detection methods evaluated for viability

• Case mounted accelerometer

• Laser Vibrometer

– Laser Vibrometer method preferred due to

ease of setup and test repeatability which

would result in higher probability of success


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• Solution

– Hardware selected:

• Laser Vibrometer: Polytec PDV-100

– Features:

• Non-contact velocity measurement from 0 to 22 kHz

• Variable working distance from 0.2 m up to 30 m

• Digital signal processing

– Benefits:

• Non-contacting measurement system

– No need to physically mount accelerometers to APU

• Portability

• Simplicity of use and setup

• Accuracy


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• Solution (cont‟d)

– Laser Vibrometer PDV-100 Operation:

1. Open APU Access Door

2. Position PDV-100 on the ground below the APU

3. Aim the PDV-100 at APU Gearbox

4. Record data with a laptop

5. Review results to identify if the APU vibration is within the “blade

walking” limits

• Status

– Awaiting operator review


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– Eductor Erosion




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Conical Seal Option for Fuel Manifold Leaks

• Issue

– Fuel manifold leaks at the

Atomizer

• Background

– Leaks result in over tightening

– Seals used on 331 Turboprop

• Status

– Honeywell incorporating into

Manual for the 131-9B


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– Eductor Erosion




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Safety Wire Chafing on Fuel Manifold

• Issue


• Background

– Operators and shops have found

heat shield safety wire chafing on

fuel manifold

• Solution

– Separate the safety wire from the

fuel manifold during maintenance

– Operators /shops notified in SIL

D200907000007

– Safety wire removal made optional


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– Eductor Erosion




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Eductor Wear

• Issue

– Operators have found Cracks / Holes in

Eductor at 07:00 position

• Background

– Boeing AMM task 49-81-41-200 Item 2. F.

b) 1) states that no cracks are permitted

and that the eductor housing must be

replaced if cracks are present

– Materials Analysis shows the wear to be

due to long term particulate erosion

• Considered Normal Wear

– Repairs are available, but only after the

APU is removed from service and the

eductor is removed from the APU


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• Condition monitoring

• No APU bleed air

• APU no-start with fault 49-41010

• No bleed air or generator after landing

• Load shed and speed droop





– Eductor Erosion




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Diffuser Housing Studs Pulled Out

• Issue

– Studs pull out over time

• Background

– Insufficient material remains

for use of oversized stud

– Temporary Repair Authorized

by Boeing

• Bolt P/N MS9557-14

• Washer NAS1149C0432R,

2 each,

• Self locking nut MS21043-4

• FTD Article 737NG-FTD-49-11005

– Shop Incoming / Outgoing Inspection of Inserts Implemented

– Once in Shop, Flange Requires Repair


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– Eductor Erosion




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Real Time Oil Level

• Issue

– Oil Level Does Not Update

• Background

– In the Version 2,4, and 5 software, the oil level

registered during start does not update.

– During interrogation of the LOQ sensor, the ECU can

register one of three possible oil levels on CDU:

1. FULL

2. ADD

3. LOW

– In the version 2 software reading on CDU remains

unchanged

– In the version 4-5 software CDU registers UNKNOWN

after 1 hour

Apu55 131-9b Appendix - Final

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