Incident Overview
On 17 July 2020, a Boeing 737-800 aircraft, registration SP-ESH, experienced a technical issue while taxiing at Katowice Airport (EPKT). The crew received a MASTER CAUTION warning accompanied by an engine control alert for engine number 1.
Sequence of Events
During taxi to the runway, the aircraft's warning system generated a "MASTER CAUTION – ENG – ENGINE CONTROL" indication for engine 1. The flight crew executed the non-normal checklist (NNC) procedure for engine verification. Following the procedure, they returned the aircraft to the parking stand and took it out of service pending rectification.
Maintenance personnel subsequently diagnosed a malfunction in the hydraulic metering unit (HMU), which supplies fuel to the combustion chambers and supports engine operation systems. The HMU was replaced with a new unit, and the aircraft was returned to service.
Cause
The investigation determined that the incident was caused by a malfunction of the engine fuel system hydraulic metering unit (HMU). No contributing factors or safety recommendations were identified.