SDR ASAA2016110218549

Service difficulty report · Hmu · Boeing 737890

Difficulty date: November 2, 2016
Submitted: November 7, 2016
Operation: Air carrier
Aircraft: N529AS
Make and model: Boeing 737890
Aircraft serial: 35198
Aircraft time: 25,861 hours, 7,776 cycles
Engine: Cfmint CFM567B20
System (JASC): 7200 · Engine (Turbine/Turboprop)
Part: Hmu
Part number: 442653
Part serial: BECW8124
Condition: Failed
Location: Nr 1 Engine
Part time: 14,938 hours, 5,633 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

FOUND FAULT CODE 73-31161, THE MECHANICAL OVERSPEED PROTECTION SIGNAL IS OUT OF RANGE, A LONG TERM FAULT, ON THE NR 1 ENGINE BITE TEST FOR LEGS 1-7. ACFT GROUNDED. REMOVED AND REPLACED THE NR 1 ENGINE HMU. TEST 3A & 12 PASS, NO LEAKS NOTED. BITE CHECK PASSED, NO CURRENT FAULTS.