Service difficulty report · Relay · Boeing 777222

Difficulty date
September 19, 2011
Submitted
September 30, 2011
Operation
Air carrier
Aircraft
N229UA
Make and model
Boeing 777222
Aircraft serial
30557
Aircraft time
40,719 hours, 4,985 cycles
Engine
Pwa PW40903
Part
Relay
Part number
406171383
Part serial
CM92116
Condition
Faulty
Location
Electrical Sys
Stage of operation
NR
How discovered
O
Nature of condition
J
Precautionary procedure
O

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

What was found

ELEC STANDBY SYS MESSAGE. REPLAC'E K24006 MAIN BATTERY RELAY, NO HELP. REPLACED RELAYS K24020 & K24019, NO HELP. ABOVE SHOULD READ RELAY K24006 NOT K24020. PRIOR TO 2ND TEST HOP, WITH AC POWERED UP FROM BATTERY ONLY, AFTER APU PWR SUPPLIED, GOT 'ELEC STANDBY SYS ' MAINT MESSAGE AND UPPER EICAS MESSAGE. INTERMITTENTLY ALSO GET 'ELEC BATTERY OFF' UPPER EICAS MESSAGE, WITH BATTERY SW 'ON'. REF:WD24-33-21SH2, DISCONNECTED D5688J, D4737P, D4836P AND D31013P, INSPECTED 'P' AND 'J' SIDES TO CK FOR PUSHED BACK PINS OR SOCKETS, NO DISCREPANCIES NOTED. RECONNECTED PLUGS AND CK'D FOR CONTINUITY TO GR (PARTI (PARTIAL). REPLACED C24640, P310 PSU B ALTN CB REF WDM24-61-31. PWR'D UP BATTERY AND EXT PWR NORMAL 9 TIMES AND 3 TIMES FROM BATTERY TO APU START SEQUENCE. TOTAL OF 12 P R UP CYCLES WITH NO FAULTS.