What happened
On October 3, 2016, at Warsaw Chopin Airport (EPWA), a Bombardier DHC-8-400 operated by PLL LOT was undergoing engine start procedures following the completion of ground handling. The crew began the sequence by attempting to start engine number 2. At 05:13 UTC, the crew observed that the engine was not accelerating as expected, noting a slow increase in the high-pressure spool speed (NH).
During this process, smoke was observed emanating from beneath the engine nacelle. This was noted by the airport coordinator. Communication between the flight crew and the coordinator was difficult due to a damaged external headset jack, necessitating the use of hand signals by the coordinator to alert the crew. Following the identification of a hang start, the crew followed the abnormal engine start checklist and shut down engine number 2. The smoke ceased once the engine was shut down. The airport fire service was dispatched to the aircraft but determined that no firefighting actions were necessary.
The investigation
The investigation, conducted by the operator, focused on the engine startup failure and the observed smoke. The crew notified Air Traffic Control (Ground) and the Maintenance Control Center (MCC) of the aborted start and recorded the event in the appropriate technical logs. Following the incident, passengers were disembarked, and the flight was subsequently operated using a different aircraft. Technical personnel performed an inspection of the aircraft, after which it was cleared for flight. The investigation included an analysis of the Digital Flight Data Recorder (DFDR) and the event was recorded in the operator's Safety Management System (SMS).
Findings
- The primary cause of the slow acceleration of engine number 2 was a hang start.
- Communication between the aircraft crew and ground personnel was hindered by a malfunction in the external headset socket.