Service difficulty report · Bypass Valve · Boeing 777222

Difficulty date
February 24, 2020
Submitted
February 29, 2020
Operation
Air carrier
Aircraft
N779UA
Make and model
Boeing 777222
Aircraft serial
26941
Aircraft time
92,142 hours, 16,639 cycles
Part
Bypass Valve
Part number
3910028103
Condition
Inoperative
Location
Nlg
Stage of operation
NR
How discovered
O
Nature of condition
J
Precautionary procedure
A

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

What was found

GEAR DISAGREE AFTER RAISING GEAR HANDLE TO UP NOSE INDICATE HASH TAG PER CREW: WHEN LANDING GEAR WAS SELECTED TO RETRACT POSITION MAIN GEAR AND MAIN GEAR DOORS RETRACTED IMMEDATELY. NOSE GEAR BEGAN TO RETRACT BUT CREW BELIEVES THAT IT NEVER RETRACTED. EICAS MESSAGE "GEAR DISAGREE" APPEARED. AT THIS TIME. MAINT MESSAGES 32-11950, 32-12800 DISPLAYED ON MAT. NOT ACTIVE GEAR DOOR MAINT MESSAGES 32-11930, 32-12780 AND GEAR DISAGREE PERFORMED FIM 32-30-00-810-805 UP TO AND INCLUDING STEP B. (2). NEXT STEP IS (3). NO DEFECTS NOTED. REMOVED AND REPLACED NLG SELECTOR BYPASS VALVE IN REF WITH AMM AND A23 AND PERFORMED GEAR SWING NO DEFECTS NOTED. PINED NLG AND SELECTED GEAR UP FOR 5 MIN, ACTUATOR TEMP WAS 79 DEG USING DIGITAL THERMOMETER. PER TOMC CONTROLLER GORMAN AND TOMC MANAGER ADD EMP:U018363,U352629,U354836 32-31-02 OPS K GOOD. PERFORMED GEAR SWING. ISOLATED PSEU CB G10 ROTABLE PARTS CHANGE WAS INDICATED - TT # 1626799 SN OFF 0016 KASEY. OK TO RETURN TO SERVICE. IPC REFERENCE # 32-31-02-01 COMPLIED WITH RII INSPECTION VERIFYING PN, INSTALLATION, LEAK AND OPS CHECK WITH GEAR SWING REF GMM 9-25-05. VALVE, AY-BYPAS OFF 27-3221-9-0012 0016 ON 27-3221-9-0012 0354