Service difficulty report · Hmu · Boeing 737890

Difficulty date
February 8, 2020
Submitted
February 14, 2020
Operation
Air carrier
Aircraft
N529AS
Make and model
Boeing 737890
Aircraft serial
35198
Aircraft time
38,280 hours, 11,340 cycles
Engine
Cfmint CFM567B27
Part
Hmu
Part number
1853M56P12
Part serial
BECW2141
Condition
Failed
Location
Nr 1 Engine
Part time
64,729 hours, 21,376 cycles
Stage of operation
IN
How discovered
9
Nature of condition
O
Precautionary procedure
K

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

What was found

#1 ENG BITE SHOWS FAULT 73-20341 THE FMV POSITION SIGNAL IS OUT OF RANGE. SHORT TIME FAULT. DEFERRED PER T/C 78273000. GROUNDED - YES. PERFORMED ENG 1 BITE FOR FLT FAULTS. VERIFIED ALL FLTS 0-10 SHOW RECORDED FAULT OF 73-20341. PERFORMED B737-800 FIM 73-25 TASK 803 INITIAL EVALUATION EEC BITE TEST - FAILS FOR SAME FAULT. PERFORMED RESISTANCE CHECK OF HMU RECEPTACLE DP0601, PINS 16 TO 34 SHOWS 19.40 MEG OHM, SHOULD BE 36 TO 90 OHMS. REVERIFIED FOUND RESISTANCE AT EEC CONN DP0606 REF PAR (6) TABLE 207/208 PINS T TO U. READS SAME 19.40 MEG. REMOVED AND REPLACED #1 ENGINE HMU REF T/C N8473000. ACCOMPLISHED TESTS IAW B737-800 AMM 71-00-00-800-811-F00 TABLE 502. NO FAULTS NOTED - GROUND VERIFICATION REPAIR CONFIRMATION SUCCESSFUL PER FIM 73-25 803.