# SDR ASAA2012100593037

- Type: Service difficulty report (as reported; unverified)
- Difficulty date: October 5, 2012
- Submitted: October 10, 2012
- Operation: Air carrier
- Aircraft: [N565AS](https://openairdocs.org/aircraft/N565AS), registered now
- Make and model: Boeing 737890
- Aircraft serial: 35181
- Aircraft time: 22,563 hours, 6,982 cycles
- Engine: Cfmint CFM567B27
- System (JASC): [4940 · APU Start/Ignition System](https://openairdocs.org/jasc/4940)
- Part: Exciter
- Part number: 38880587
- Part serial: 110821
- Condition: Inoperative
- Location: Apu
- Part time: 249 hours, 598 cycles
- Stage of operation: CR
- How discovered: O
- Nature of condition: J
- Precautionary procedure: O
- FAA source: FAA Service Difficulty Reporting System (https://sdrs.faa.gov/)
- Page: https://openairdocs.org/sdr/ASAA2012100593037

## Discrepancy

ATTEMPTED THREE COLD SOAK STARTS ON THE APU AT FL 400, ALL THREE ATTEMPTS RESULTED IN FAULT LIGHTS ILLUMINATING.  REMOVED AND REPLACED IGNITION UNIT REF MM 49-41-31. PERFORMED FIM TASK 49-40 TASK 85. DISCONNECTED D10434 AND P13. CHECKED PINS 16/17 AND 2/1. NO FAULTS FOUND. REINSTALLED BOTH PLUGS D10434 AND P13. PERFORMED APU BITE TEST 49-60 TASK 801. FAULT 49-41181 STILL ACTIVE. SUGGEST REPLACING IGNITION CONTROL UNIT. PERFORMED APU GROUND START FOUR TIMES FAULT NOT ACTIVE. SYS CHECKED NORMAL. REF 49-11-00-710-801. SYS RETURNED TO NORMAL.

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