Flight Details
The aircraft departed Bari at 1432 local time on flight TUI1153 to Djerba. On board were 39 people: 4 crew members and 35 passengers, including an airline engineer.
Engine Failure and Ditching
Approximately 50 minutes after takeoff, while cruising at flight level 230, the right engine shut down. About 100 seconds later, the left engine also shut down. The flight crew decided to divert to Palermo's Punta Raisi airport for a precautionary landing. They attempted to restart both engines but were unsuccessful.
After gliding for approximately 16 minutes, the aircraft ditched into the sea about 23 nautical miles northeast of Palermo's airport, within Italian territorial waters. On impact with the sea surface, the aircraft broke into three pieces. Fourteen passengers, the airline engineer, and a senior flight attendant (a crew member) reported fatal injuries. The other occupants suffered injuries ranging from serious to minor.
Investigation Findings
The official investigation determined that the ditching was primarily due to both engines flaming out because of fuel exhaustion. The incorrect replacement of the fuel quantity indicator (FQI) was a contributing factor, leading to an erroneous fuel quantity indication. The accident's cause was traced to an incorrect procedure used by the operator's maintenance personnel when replacing the FQI.
Several contributing factors were identified:
- Errors by ground mechanics in searching for and correctly identifying the fuel indicator.
- Errors by the flight crew, including non-compliance with various operational procedures.
- Inadequate checks by the operator's competent office regarding crew adherence to procedures.
- Inaccuracy of information in the aircraft management and spares information system, and lack of effective control over the system.
- Inadequate training for system use and absence of a responsible person for managing the system.
- Unsatisfactory maintenance and organization standards for adequate aircraft management.
- Lack of an adequate quality assurance system.
- Inadequate surveillance of the operator by the competent Tunisian authority.
- Installation characteristics of FQIs for ATR 42 and ATR 72 that allowed installing an ATR 42 FQI in an ATR 72, and vice versa.
The analysis applied Reason's "Organizational accident" model. Active failures included errors by mechanics the day before the event while replacing the FQI, and by the crew who did not verify and complete aircraft documentation fully. Latent failures remained hidden in the operator's organizational system until active errors overcame defense barriers. The error that led to the accident occurred in an organizational setting where, if all had operated correctly, the accident likely would not have occurred. Inaccurate information in the management system and ineffective control were considered latent failures. The flight crew and maintenance personnel did not receive sufficiently effective aid from the system to avoid their errors.