Service difficulty report · Shutoff Valve · Boeing 7378H4

Difficulty date
May 6, 2024
Submitted
May 7, 2024
Operation
Air carrier
Aircraft
N8523W
Make and model
Boeing 7378H4
Aircraft serial
36969
Aircraft time
24,475 hours, 12,067 cycles
Part
Shutoff Valve
Condition
Malfunctioned
Location
Engine
Stage of operation
CL
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

ACFT DEPARTED BLEEDS OFF. GOT CABIN ALTITUDE WARNING AT 12;500. PERFORMED QRH STEPS IMMEDIATE ACTION. BLEEDS TURNED ON. CABIN PRESSURIZATION IN MANUAL. OUTFLOW VALVE AND VSI RESPONDED CORRECTLY. CABIN ALTITUDE SHOWED 25000 FT AT 11000FT. CABIN DIFFERENTIAL AT 8.8 CAPT AND FO USED O2<[01] PERFORMED CONDITIONAL INSPECTION PER AMM 05-51-81; FOUND NO DISCREPANCIES. PERFORMED CONDITIONAL INSPECTION PER AMM 05-51-91 AND PACK CONFIDENCE PER MT 734-00-03. FOUND ENG 2 BLEED PRESSURE TO BE LOW AT IDLE (10 PSI). FOUND ENG 2 PRSOV; HSR; AND RH PRECOOLER SENSE LINE LEAKING. R+R #2 PRSOV PER AMM 36-11-04. R+R #2 HSR PER AMM 36-11-07. R+R RIGHT PRECOOLER SENSE LINE PER SIP. OPS AND LEAK CHECKS GOOD. PACK CONFIDENCE CHECK PASS. PERFORMED BITE TEST OF CPC?S FOUND FAULTS 30 AND 58 IN HISTORY. FAULT?S WERE SET DURING MANUAL OVERRIDE OF OUTFLOW VALVE. SUSPECT OPERATOR ERROR. CPC?S BITE SYSTEM TEST PASS. NO OTHER FAULTS FOUND. OK FOR SERVICE.

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