What happened
On August 9, 2018, a Bombardier DHC-8-402 (Q400), registration TF-FXA, declared an emergency approximately two minutes after departing runway 31 at Reykjavik Airport (BIRK). The aircraft experienced a loss of oil pressure in the right engine. The flight crew responded by shutting down the affected engine and successfully performed an emergency landing with one engine inoperative. There were no injuries and no damage to the aircraft.
Following the landing, a significant oil leak was discovered in the right engine nacelle. Investigation revealed that the retaining ring intended to secure the oil nozzle to the starter drive access cover had detached, along with the nozzle itself, both of which were found inside the engine nacelle.
The investigation
The RNSA investigation focused on maintenance activities performed prior to the flight. The aircraft had been undergoing borescope inspections of the engines. While the left engine inspection was completed the previous evening, the right engine inspection was scheduled for the morning of the incident. Due to operational pressures and the need to facilitate additional flights to Greenland, maintenance schedules were accelerated.
The investigation examined the staffing levels and qualifications of the maintenance crew. On the morning of the incident, the primary qualified engineer (Engineer A) had been reassigned to another aircraft at Egilsstaðir. The remaining tasks were performed by Engineer B, who had completed practical training but had not yet applied for his EASA Part-66 license, and a maintenance trainee (Trainee C).
Furthermore, the investigation found that the engineer responsible for the independent inspection (Engineer D) was simultaneously managing tasks at a battery workshop and providing remote assistance to the engineer in Egilsstaðir. This prevented a thorough, independent verification of the critical maintenance task.
Findings
- The oil nozzle was not seated deeply enough into the starter drive access cover; the retaining ring failed to engage with its intended groove because the nozzle was improperly positioned.
- The lack of qualified engineers with the appropriate type ratings available on the line maintenance shift was the primary cause of the incident.
- Maintenance personnel and management succumbed to operational pressure to return the aircraft to service, leading to deviations from established procedures.
- There were significant failures in maintenance documentation, including an engineer signing off on work while being physically located at a different airport, and a trainee performing tasks without proper oversight.
- The maintenance management failed to ensure that the required number of authorized personnel were available to perform and certify critical tasks.