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SDR ASAA2017031620217

Open the Markdown

Service difficulty report · Thermocouple · Boeing 737990ER

FAA SDR system

Difficulty date
March 16, 2017
Submitted
March 20, 2017
Operation
Air carrier
Aircraft
N423AS
Make and model
Boeing 737990ER
Aircraft serial
35206
Aircraft time
15,474 hours, 5,090 cycles
System (JASC)
4970 · APU Indicating System
Part
Thermocouple
Part number
38762711
Condition
Failed
Location
Apu
Stage of operation
IN
How discovered
O
Nature of condition
O
Precautionary procedure
K

As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.

What was found

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.