Service difficulty report · Drive Unit · Cessna 750

Difficulty date
January 6, 2025
Submitted
January 10, 2025
Operation
Air carrier
Aircraft
N901UP
Make and model
Cessna 750
Aircraft serial
7500137
Aircraft time
18,942 hours, 11,551 cycles
Part
Drive Unit
Part number
99146153
Part serial
430A
Condition
Intermittent
Location
Flap Sys
Part time
7,065 hours
Stage of operation
CL
How discovered
O
Nature of condition
F
Precautionary procedure
A

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

What was found

FLAPS FAIL MESSAGE OCCURED AFTER TAKEOFF/ENROUTE, POSTION INDICATED FALPS 0 AND SLATS NOT EXTENED. EMERGENCY DECLARED. T/S FLAPS SYSTEM. POWERED AIRCRAFT AND REVIEWED BIT CHECK ON FLAP CONTROLLER, FLAP CONTROLLER SHOWED BIT FAULT 2 (MOTOR FAULT) ANO BIT FAULT 6 (NO COMMAND). CLEAR FAULTS AND RAN FLAPS THROUGH SEVERAL CYCLES AND MONITORED THE DC CURRENT TO PDU. FOUND NO FAULTS LOGGED IN FLAP CONTROLLER. FLAP FROM FULL UP TO FULL. DOWN SHOWED 36 AMPS ANO FROM FULL DOWN TO FULL UP WAS 32 AMPS. WITH FLAPS DOWN, INSPECTED L/H AND R/H FLAP TRACKS, ROLLERS AND ACTUATORS FOR ANY SIGNS OF DAMAGE. NO DAMAGE NOTED. T/S SYSTEM FURTHER. PER WUP FSR, REMOVED THE FLAP HANDLE AND CLEANED THE INTERNALS OF DUST AND DEBRIS. SMALL AMOUNT OF DEBRIS FOUND. REINSTALLED FLAP HANDLE AS REQUIRED. REMOVED FLAP PDU P/N MP50G-4 S/N 430A AND INSTALLED A "OVERHAULED" FLAP PDU P/N MP50G-4 S/N 166B AS NEEDED. PERFORMED FLAP OPERATIONAL CHECKS. ALL CHECKS FOUND GOOD. NO FAULTS POSTED ON ELCAS OR FLAP CONTROLLER. ALL WORK DONE IAW CE75O AMM 27-52-00.

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