Service difficulty report · Overheat Loop · Boeing 737990ER
FAA SDR system
- Difficulty date
- September 25, 2019
- Submitted
- October 3, 2019
- Operation
- Air carrier
- Make and model
- Boeing 737990ER
- Aircraft serial
- 36354
- Aircraft time
- 22,600 hours, 7,287 cycles
- Part
- Overheat Loop
- Part number
- 90202001
- Condition
- Failed
- Location
- Apu Bay
- Stage of operation
- IN
- How discovered
- C
- Nature of condition
- L
- Precautionary procedure
- K
As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
APU DETECTOR INOPERATIVE LIGHT. GROUNDED - YES. CONFIRMED FAULT, APU WILL NOT TEST. ACCOMPLISHED APU FIRE DETECTION LOOP RESISTANCE, SYSTEM TESTED IAW AMM 26-15-00-730-801 & RE-CONFIRMED APU TAIL PIPE OVERHEAT DETECTOR ASSY M1925 WAS DEFECTIVE, SHOWS 1.7M OHM INSTEAD OF 3.94K OHMS. REMOVED & REPLACED THE M1925 OVERHEAT DETECTOR ASSY IAW AMM 26-15-01. APU FIRE DETECTION OPS CHECKED NORMAL IAW AMM 26-15-00-710-801.