SDR SWAA2026101481039

Service difficulty report · Hmu · Boeing 7377H4

Difficulty date: October 10, 2026
Submitted: October 15, 2026
Operation: Air carrier
Aircraft: N478WN
Make and model: Boeing 7377H4
Aircraft serial: 33989
Aircraft time: 72,656 hours, 43,648 cycles
Engine: Cfmint CFM567B242
System (JASC): 7320 · Fuel Controlling System
Part: Hmu
Condition: Faulted
Location: Nr 1 Engine
Stage of operation: TO
How discovered: O
Nature of condition: R, J
Precautionary procedure: C

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

What was found

AUTOTHROTTLE OVER-CONTROLS. ON AUTOTHROTTLE ENGAGEMENT ON RUNWAY, THRUST LEVERS WERE EVEN BUT NR 1 ENGINE REMAINED AT 40%, WHILE NR 2 ENGINE SPOOLED UP TO APPROX 70%, A 30% SPLIT IN N1 INDICATION. REJECTED TAKEOFF, REMOVED & REPLACED NR 1 HMU IAW AMM 73-21-10. REMOVED AND REPLACED NR 1 EEC IAW AMM 73-21-60.

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