SDR ASAA2018082825932

Service difficulty report · Probe · Boeing 737990ER

Difficulty date: August 28, 2018
Submitted: August 28, 2018
Operation: Air carrier
Aircraft: N459AS
Make and model: Boeing 737990ER
Aircraft serial: 36352
Aircraft time: 18,020 hours, 5,965 cycles
System (JASC): 4960 · APU Controls
Part: Probe
Condition: Malfunctioned
Location: Apu Bay
Part time: 18,020 hours, 5,965 cycles
Stage of operation: IN
How discovered: 9
Nature of condition: J
Precautionary procedure: K

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

What was found

APU WAS EXPERIENCING MULTIPLE ISSUES. HIGH CT5ATP AND FAULT CODE 49-71149, AND WAS SURGING DURING ENGINE START. ACFT GROUNDED. REPLACED THE APU ENGINE HARNESS IAW AMM 49-11-01/401. ACCOMPLISHED FIM 49-40/825 D. 7, 8. FOUND EGT PROBE NR 1 CASE TO TERMINALS 30K-40K OHMS. REPLACED BOTH EGT PROBE NR 1 AND 2 IAW AMM 49-71-21/401. APU OPS TEST PASSED AND APU BITE PASSED WITH NO FAULTS. IAW AMM 49-11-00-710-801. REPLACED APU ECU. ECU INSTALLATION PASSED IAW AMM 49-61-12/401.