What happened
On 9 September 2012, a DHC-8-315Q operated by Abu Dhabi Aviation departed Abu Dhabi International Airport for a scheduled flight to Das Island Airport. The aircraft, registration A6-ADB, was carrying 49 people at the time of departure. Shortly after takeoff, and while the aircraft was climbing below 5,000 feet, a passenger noticed blistering paint on the inboard panel of the right-hand engine through a cabin window.
Upon being alerted by the passenger, the co-pilot inspected the area and suspected a potential engine fire. The crew declared a PAN-PAN emergency, and air traffic control cleared the aircraft for an immediate return to Abu and Dhabi. Although cockpit instruments showed normal parameters, the crew elected to land immediately due to the perceived fire risk. Upon landing, airport fire services inspected the aircraft and found no evidence of an active fire, and there were no injuries reported.
The investigation
The UAE Air Accident Investigation Sector (GCAA AAIS) examined the maintenance history of the aircraft, specifically focusing on engine cleaning procedures performed the day prior to the incident. The investigation scrutinized the operator's maintenance documentation, quality management oversight, and the physical condition of both engines. Investigators looked into the procedures for engine turbine washes and how the maintenance tasks were recorded and supervised.
Findings
The investigation established that the primary cause of the incident was the failure to re-install the LH engine igniters on both engines following a recent maintenance action. This error was driven by several contributing factors, including:
- Performing maintenance tasks without utilizing proper reference documentation.
- Incomplete or unrecorded maintenance work.
- Deficiencies in quality management oversight.
- Personnel fatigue and issues related to duty time management.
- Inadequate implementation of a Safety Management System (SMS) regarding risk mitigation.
Safety action
Following the investigation, the AAIS issued 14 safety recommendations. Eight were directed to the operator and six to the GCAA. These recommendations addressed critical areas such as human factors training, the identification of critical maintenance tasks, fatigue risk management, and the improvement of documentation and quality audits.