# SDR ASAA2017031620217

- Type: Service difficulty report (as reported; unverified)
- Difficulty date: March 16, 2017
- Submitted: March 20, 2017
- Operation: Air carrier
- Aircraft: [N423AS](https://openairdocs.org/aircraft/N423AS), registered now
- Make and model: Boeing 737990ER
- Aircraft serial: 35206
- Aircraft time: 15,474 hours, 5,090 cycles
- System (JASC): [4970 · APU Indicating System](https://openairdocs.org/jasc/4970)
- Part: Thermocouple
- Part number: 38762711
- Condition: Failed
- Location: Apu
- Stage of operation: IN
- How discovered: O
- Nature of condition: O
- Precautionary procedure: K
- FAA source: FAA Service Difficulty Reporting System (https://sdrs.faa.gov/)
- Page: https://openairdocs.org/sdr/ASAA2017031620217

## Discrepancy

ENGINEERING REQUESTS THE FOLLOWING TROUBLESHOOTING FOR CT5ATP FLUCTUATION. GROUNDED - YES. ACCOMPLISHED APU BITE CHECK, NO FAULTS NOTED, REF AMM 49-61-00-700-801. ACCOMPLISHED APU BLEED AIR LEAK CHECK, NO FAULTS NOTED, REF AMM 49-11-00-860-801. REMOVED AND REPLACED BOTH APU EGT THERMOCOUPLES, REF AMM 49-71-21-000-801 AND 49-71-400-801. APU OPS CHECK GOOD, REF AMM 49-11-00. ACCOMPLISHED APU BITE CHECK AGAIN, NO FAULTS NOTED, REF AMM 49-61-00.

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