What happened
On August 6, 2005, an ATR 72, registration TS-LBB, was operating flight TUI 1153 from Bari, Italy, to Djerba, Tunisia. During the cruise phase of the flight, the aircraft experienced a simultaneous loss of power in both engines. The crew declared a 'MAYDAY' emergency and, after attempting to manage the situation, determined that the aircraft could not maintain altitude.
Following the engine flameouts, the crew prepared the cabin for an emergency landing and executed a ditching in the sea off the coast of Capo Gallo, near Palermo. While the aircraft sustained significant damage upon impact with the water, there were no fatalities among the passengers or crew, though various injuries were reported.
The investigation
The ANSV investigation focused on the sequence of events leading to the dual engine failure, specifically examining the fuel system and the aircraft's maintenance history. Investigators analyzed the Flight Data Recorder (FDR) and Cockpit Voice Recorder (CVR) to reconstruct the engine flameout timeline.
The inquiry also scrutinized the fuel management procedures and the recent maintenance performed on the aircraft. Specifically, the investigation looked into the replacement of a Fuel Quantity Indicator (FQI) performed prior to the flight. Technical tests, including ground refueling trials and flight simulator sessions, were conducted to evaluate the aircraft's performance during single-engine and dual-engine failure scenarios. The investigation also reviewed the accuracy of the fuel quantity indications provided to the crew during the flight.