Service difficulty report · Transmitter · Boeing 757224

Difficulty date
March 16, 2020
Submitted
March 21, 2020
Operation
Air carrier
Aircraft
N19117
Make and model
Boeing 757224
Aircraft serial
27559
Aircraft time
96,972 hours, 20,373 cycles
Part
Transmitter
Condition
Faulty
Location
Apu
Stage of operation
UK
How discovered
O
Nature of condition
N
Precautionary procedure
K

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

What was found

AUXILIARY POWER UNIT EICAS MESSAGE APU OIL QTY DISPLAYED AND OIL QTY READS ADD (ON AIRPLANES WITH OIL QUANTITY TRANSMITTER) INDICATION ON STATUS PAGE ON CLIMBOUT THEN 0.25 OIL QUANTY SHOWS AT CRUISE REQUEST MEL 4994B. APU OIL VERIFIED FULL AT SIGHT GLASS APU VERIFIED FULL FORWARD TO MEL 4994B OIL LEVEL VERIFIED FULL ON SIGHT GLASS REMOVED AND REPLACED OIL PRESSURE SWITCH AS AMM 49-94-02-402-008. WHILE WORKING FOUND IGNITION LEAD TO EXCITOR BOX WITH CORROSION. REMOVED AND REPLACED IGNITION LEAD,EXCITOR BOX AND PLUG AS PER AMM 49-41-03-400-011 AS A PRECAUTION. NEED TO REMOVE DDP AND PERFORM OPS AND LEAK CHECK AND ENSURE NO FAULTS IS DETECTED. ROTABLE PARTS CHANGE WAS INDICATED - TT # 1037401 SN OFF 6144 IPC REFERENCE # 49-41-00 REF LOG PAGE 4721767 FOR UPDATED PART CHANGE. EXCITER, IGNITI OFF 99-4940-9-9001 8058 ON 99-4940-9-9001 0618 REMOVED APU PER AMM 49-11-01. APU FIRE WALL INSPECTION C/W. TWO LOG PAGES GENERATED. REF L/P 4721767 FOR APU CHANGE, NO HELP. NEEDS FURTHER TROUBLESHOOTING. REMOVED AND REPLACED APU OIL QUANTITY TRANSMITTER PER AMM 49-94-04. OPS AND LEAK CHECK GOOD. MEL CLEARED.