Service difficulty report · Fmc · Boeing 757224

Difficulty date
June 29, 2025
Submitted
July 1, 2025
Operation
Air carrier
Aircraft
N33103
Make and model
Boeing 757224
Aircraft serial
27293
Aircraft time
116,522 hours, 25,070 cycles
Part
Fmc
Part number
4052506955
Part serial
93117559
Condition
Faulted
Location
Left
Part time
86,983 hours, 20,909 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

NO VERTICAL PATH OR FUEL OR TIME INFO AVAILABLE UPON DEPARTURE. AIRCRAFT 103 RETURNED TO SHANNON AFTER APPROX 1 HOUR OF FLIGHT. CAPTAIN REPORTED THAT ONCE THEY REACHED THEIR REQUIRED FLIGHT L EVEL HE NOTICED THAT THE VNAV WAS INOP (VERTICAL PATH). THE FUEL FLOW INFO ON HIS PROGRESS PAGE ON THE CDU WAS NOT AVAILABLE AND THE TIME INFO ON THE PROGRESS PAGE WAS NOT AVAILABLE. ON DESCEN T AT ABOUT 3000 FT ALL INFO RETURNED TO NORMAL. MOC CONSULTED AN D THEY REQUESTED THAT A MCDP GROUND TEST 30 TO BE PERFORMED. MCDP GROUND TEST 30 - CURRENT FAULT REPORT C/O IAW FIM 22-03 FT 842 REV 137. THE FOLLOWING CURRENT FAULTS WERE SHOWN - FMC L/TMC , FMC L-R CH, FMC R/TMC, FMC L-R CH, MODE ERR. AFTER FURTHER CON SULTATION WITH MOC AND T/S THE L FMC REQUIRES REPLACEMENT. REPLA CED LH FMC IAW AMM 34-61-01-424-005-002 REV 137. FMC SOFTWARE CR OSSLOAD C/O SATIS IAW AMM 34-61-00-342-009-004 REV 137. LH FMC I NS OPS CHECK C/O SATIS IAW AMM 34-61-00 REV 137. MCDP GROUND TEST 30 - CURRENT FAULT REPORT C/O IAW FIM 22-03 FAULT TREE 842 REV 137. THE FOLLOWING CURRENT FAULTS WERE SHOWN - TMC DATA IN NCD. CONSULTED WITH MOC AND THIS FAULT IS DUE TO THE DEFERRED LP 5361120 (AS THERE IS NO EPR INDICATION ON ENG 2). AIRCRAFT OK TO CONTINUE.