Service difficulty report · Transmission · Boeing 75733N

Difficulty date
September 9, 2025
Submitted
September 15, 2025
Operation
Air carrier
Aircraft
N57869
Make and model
Boeing 75733N
Aircraft serial
32593
Aircraft time
64,274 hours, 19,455 cycles
Part
Transmission
Part number
251N405060
Part serial
0505
Condition
Tripped
Location
Te Flaps
Part time
53,935 hours, 1,628,200 cycles
Stage of operation
AP
How discovered
O
Nature of condition
J, F
Precautionary procedure
O

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

What was found

TE FLAP DISAGREE ON APPROACH. FLAPS STUCK BETWEEN 15/20. RAN QRH. WHEN FLAPS WERE SET TO 20, FLAPS STOPPED MOVING HYDRAULICALLY BETWEEN 15 & 20 DEGREES & HAD A TE DISAGREE MESSAGE. FLAPS HAD TO BE MOVED TO 20 IN ALT MODE FOR LANDING IAW QRH. REF FIM 27-51 TASK 808. PERFORMED FSEU BITE PROCEDURE, FOUND MSG 305 ON FSEU 1 & MSG 327 ON FSEU 2 INSPECTED TE FLAP OVER TORQUE INDICATORS ON ALL FLAP TRANSMISSIONS IAW FIM 27-51 FAULT TREE 808. FOUND OVER TORQUE INDICATORS TRIPPED ON LT & RT OTBD FLAP, OTBD TRANSMISSIONS. THESE INDICATORS WERE ALSO FOUND TRIPPED ON AUG 02 AT SFO FOR SAME WRITE UP. ACFT HAS HISTORY FOR FLAP ISSUES. REMOVED LT WING TRANSMISSION FOR OTBD TE FLAP IAW AMM 27-51-17-024-001. LT SIDE X DIMENSION IS 11 7/8", ACCOMPD RII REQUIREMENTS FOR PREINSTALL IAW GMM 09-25-05. INSTALLED LT FLAP NR 1 XMISSION. PERFORMED BITE TEST OF FSEU 1 & 2 IAW FIM 27-51 TASK 808 BITE TEST GOOD, NO EXISTING FAULTS NOTED.

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