What happened
On February 8, 2015, a Bombardier DHC-8-400 operated by Eurolot SA was performing a scheduled flight from Rzeszów (EPRZ) to Warsaw. During the initial phase of the takeoff roll, once the aircraft reached a speed of approximately 35 knots, a warning light appeared on the Crew Warning panel indicating a fault in the left AC bus ("L AC BUS").
Upon detecting the malfunction, the crew immediately aborted the takeoff. The aircraft returned to its parking position, and the crew notified Air Traffic Control (ATC) of the situation. The technical issue was reported to the Maintenance Control Center (MCC), and the incident was documented in the aircraft logbook. As a result of the malfunction, the return flight to Warsaw was canceled.
The investigation
The investigation focused on the electrical system failure and the subsequent maintenance actions. Maintenance personnel arrived on the following flight to perform a technical analysis of the aircraft's systems. The inspection identified a malfunction within the left engine's Generator Control Unit (GCU).
Findings
- The primary cause of the incident was a failure of the AC GCU on the left engine.
- Following the identification of the faulty component, mechanics replaced the unit in accordance with the Aircraft Maintenance Manual (AMM).
- After the replacement, engine tests were conducted successfully, and the aircraft returned to service for its flight to Warsaw without further issues.