Service difficulty report · Unknown · Boeing 777222

Difficulty date
September 3, 2023
Submitted
September 6, 2023
Operation
Air carrier
Aircraft
N778UA
Make and model
Boeing 777222
Aircraft serial
26940
Aircraft time
99,728 hours, 17,787 cycles
Part
Unknown
Part number
38790081
Part serial
CUA10541
Condition
Faulty
Location
Apu
Part time
3,574 hours, 944 cycles
Stage of operation
CL
How discovered
O
Nature of condition
J, O
Precautionary procedure
A

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

What was found

APU EICAS STATUS APUC DETECTED FAULT THAT WOULD CAUSE AUTOMATIC SHUTDOWN OF APU IN UNATTENDED MODE OPERATION, OR COMPLETE LOSS OF APUC BUS ACTIVITY (BOTH L AND R 629) FOR 3 SECONDS AFTER THE APU MASTER CONTROL SWITCH HAS BEEN IN THE ON POSITION FOR TEN SECONDS. FIM TASK REF : FIM TASK REFERENCE NOT FOUND CMC MSG# 4910270 FLIGHT STATUS: I INTERMITTENCE CODE: M PH: CLIMB NARRATIVE: APU CONTROLLER (APUC) REMOVED AND REPLACED OIL QTY/SUMP TEMP SENSOR. REF MM 49-94-01. NO HELP. NEEDS FURTHER TROUBLESHOOTING. ROTABLE PARTS CHANGE WAS INDICATED - TT # 1270851 SN OFF 1717 REMOVED AND REPLACED APU FUEL CLUSTER. REF. AMM 49-31-31. OPS CHECK AND LEAK CHECK GOOD. ROTABLE PARTS CHANGE WAS INDICATED - TT # 1820567 SN OFF 0541. R/R INLET TEMP SENSOR (T2) M49001M007 PER AMM 49-61-03 SENSOR, LOW OIL OFF 26-4927-9-9003 1717 ON 26-4927-9-9003 0580 SENSOR, LOW OIL OFF 26-4927-9-9003 1717 ON 0000 IPC REFERENCE # 49-31-31-01 CLUSTER, FUEL ( OFF 25-4931-9-0001 0641 ON 25-4931-9-0001 0136 CLUSTER, FUEL ( OFF 25-4931-9-0001 0641 ON 0000. REMOVED AND REPLACED APU LUBE CLUSTER IAW AMM 49-27-27/401. PARTS USED: 25-4927-9-0003,QTY :1 ROTABLE PARTS CHANGE WAS INDICATED - TT # 1745146 SN OFF 0458 UNIT, CLUSTER A OFF 25-4927-9-0003 0458 ON 25-4927-9-0003 0122 UNIT, CLUSTER A OFF 25-4927-9-0003 0458 ON 0000 R&R M49001 CANNON PLUG IN REF SPWM 20-63-13 AND WDM 49-94-11-3. PERFORMED WIRING CHECK. CHECK OK. PERFORMED APU OPERATION IAW AMM 49-11-00-860-804 FOR 60 MINUTES AND LEAK CHECK. NO DEFECTS NOTED. PERF