Service difficulty report · Modulating Valve · Boeing 75733N

Difficulty date
May 17, 2025
Submitted
May 20, 2025
Operation
Air carrier
Aircraft
N57869
Make and model
Boeing 75733N
Aircraft serial
32593
Aircraft time
63,272 hours, 19,156 cycles
Part
Modulating Valve
Part number
3987865
Part serial
3773
Condition
Faulted
Location
Zone 100
Part time
784,362 hours, 718,552 cycles
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

COCKPIT TEMP TOO HOT AND TEMPO UNCOTROLLED AFTER QRH TEMP EVENTU ALY BEGAN TO COME DOWN PER PILOTS-ON THE TAKEOFF ROLL COCKIT VENT OUTLETS POURED OUT AIR THAT WAS EXTREMELY HOT. IN THE CLIMB TEMPS CONTINUED LET OUT HOT AIR. EVENTUALLY AFTER RUNNING QRH TEMPS STARTED TO RETURNTO NORMALL, WITH CONTROLLERS IN THESBY-C POSITION. FOLLOWED FIM 21-60 FAULT TREE 809 AND COCKPIT VALVE NOT FULLY RESPONDING, SUSPECT VALVE NEEDS REPLACED PER FIM. REMOVED AND REPLACED FLT DECK TRIM AIR VALVE IAW 21-61-07-404-031 UP TO BUT NOT INCLUDING STEP F (12) OPERATIO AND LEAK CHECKS , PERFORMED CLEANING OF FLT DECK TEMP CONTROL SENSOR PER SERVICE TIP 21-61-00/201. COMPLETED INSTALLATION OF FLIGHT DECK TRIM AIR MODULATING VALVE REF AMM 21-61-07. OPS CHECK LEAK CHECK GOOD. REF FIM 21-60 FAULT TREE 809. BITE TEST GOOD. NO FAULT NOTED.

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