Service difficulty report · Hmu · Boeing 737890

Difficulty date
July 2, 2011
Submitted
July 7, 2011
Operation
Air carrier
Aircraft
N593AS
Make and model
Boeing 737890
Aircraft serial
35107
Aircraft time
12,446 hours, 4,036 cycles
Engine
Cfmint CFM567B27
Part
Hmu
Part number
1853M56P12
Part serial
BECW4133
Condition
Faulted
Location
Nr 1 Engine
Part time
22,421 hours, 7,826 cycles
Stage of operation
IN
How discovered
O
Nature of condition
J
Precautionary procedure
K

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

What was found

FMC/CDU BITE CK FAIL NR 1 ENG SHORT TIME FAULT OF 50 HRS MESSAGE NR 73 20341 THE VMF POSITION SIGNAL IS OUT OF RANGE. ACCOMPLISHED EEC BITE FAULT STILL ACTIVE EVERY LEG (73 20341 IS ONLY FAULT). REF FIM 73 25 803 STEP F.(4): TABLE 205 PIN 16 34 SHOWS OPEN. REPLACED HMU IAW AMM 73 21 10 000 801 F00. ACCOMP HMU INSTALLATION TESTS PER M/M 71 00 00 700 ALL TESTS GOOD. ACCOMP REPAIR CONFIRMATION PER FIM 73 25 00 810 803 F00.