Service difficulty report · Control Valve · Boeing 737824

Difficulty date
July 15, 2024
Submitted
July 23, 2024
Operation
Air carrier
Aircraft
N18243
Make and model
Boeing 737824
Aircraft serial
28806
Aircraft time
75,364 hours, 27,611 cycles
Part
Control Valve
Part number
3966081
Part serial
7089
Condition
Faulty
Location
Rt A/C Pack
Part time
28,867 hours, 11,230 cycles
Stage of operation
TO
How discovered
O
Nature of condition
O
Precautionary procedure
A

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

What was found

PRESSURIZATION CANNOT KEEP THE CORRECT CABIN PRESSURE AC DID NOT PRESSURIZE MANUAL MODE DID NOT CONTROL OUTFLOW VALVELOG PAGE LOCKED BY TOMC. BITE TEST OF DCPC 1 & 2 PER FIM TASK 21-31 TASK 801. DCPC 1 & 2 FAULT HISTORY RECORDED ON FLIGHT LEG OO, FAULT CODE 0058, MANUAL SWITCH MESSAGE, CAB PRESS 10.02,AMB PRESS 10.13PSI,CAB RATE +61FPM,AIRCRAFT RATE +7FPM,FLT ALT +25000FT, LAND ALT 1000FT,OFV 0 DEG OPEN,OSD MODE. DCPC BITE TESTED OK ON GROUND. NO EXISTING FAULTS SHOWS. OFV ALTERNATE AND MANUAL TESTED OK. PHOTO INFO ONLY. PHOTOS FOR INFO. PLEASE REPLACE THE RH FLOW CONTROL/SHUT OFF VLV IAW AMM 21-51-01 PB.401 AND VERIFY INSTALLATION TEST TO CONFIRM IT IS COMMANDED TO HIGH FLOW PASSES.ACCOMPLISH A CABIN PRESSURE LEAK TEST PER AM M 05-51-91-790-801 ONCE PACKS ARE OPERATIONAL.TO VERIFY NO OTHER PRESSURIZATION ISSUES ARE PRESENT.SFOLM POZAS REMOVED AND REPLACED RH PACK FLOW CONTROL VALVE REF MM TASK 21-51-01-000-805-002. LEAK CHK, ZONE TEMP BITE AND OPS CHK GOOD. ALSO PERFORMED CABIN PRESSURE LEAK TEST REF MM TASK 05-51-91-790-801. WITH OUTFLOW VALVE FULLY CLOSED, CABIN ADD EMP:U354228 DIFFERENTIAL PRESSURE ROSE TO A LITTLE ABOVE 1 PSI FOR 20 MINS. INCLUDED PARTS TRANSACTION ROTABLE PARTS CHANGE WAS INDICATED - TT # 1519287 SN OFF 7089 VALVE, CONTROL, OFF 58-2151-9-0005 7089 ON 58-2151-9-0005 6380 TECH SUPP UPDATE: ACP HEAT EXCHANGER - CLEAN WITH SOAP-ACP AIRPLANE PACK OPERATIONAL CONFIDENCE CHECK REF AMM 21-00-05-780-801. RUN UP AND DOWN SEVERAL TIMES HELD 4 PSI. ADDED PICS