Tuninter Flight 1153

Tuninter Flight 1153 was a Tuninter Airlines flight from Bari International Airport in Bari, Italy, to Djerba-Zarzis Airport in Djerba, Tunisia. On 6 August 2005, the Tuninter ATR-72 ditched into the Mediterranean Sea about 18 miles (29 km) from the city of Palermo. Sixteen of the 39 people on board died. The accident resulted from engine fuel exhaustion due to the installation of fuel quantity indicators designed for the ATR 42 in the larger ATR 72.

Flight crew
The Captain was Chafik Al Gharbi (شفيق الغربي) and the copilot was Ali Kebaier Al-Aswad (علي كبيّر الأسود).

History
The aircraft, an ATR 72, had its fuel quantity indicator (FQI) replaced the night before the flight, but technicians inadvertently installed a FQI designed for the ATR 42, a similar but smaller airplane with smaller fuel tanks. Ground crews and the flight engineer, relying on the incorrect readings from the newly-installed FQI, loaded the aircraft with an inadequate amount of fuel for the flight.

On the flight from Bari to Djerba, both engines cut out in mid-flight. The aircraft's right engine failed at 23,000 feet (7,000 metres). The aircraft began to descend to 17,000 feet, but 100 seconds after the right engine failure, the left engine also failed. The flight crew did not detect the fuel exhaustion because the incorrectly installed ATR 42 gauge indicated an adequate amount of fuel in the tanks, even after all of the usable fuel had been consumed. After the engine failure, the Captain requested an emergency landing in Palermo, Sicily. The crew tried repeatedly but unsuccessfully to restart the engines as they navigated to Palermo. The ATR glided for 16 minutes, but was unable to reach the runway and the plane was forced to ditch into the sea 23 nautical miles (43 kilometres) northeast of Palermo International Airport. The aircraft broke into three sections upon impact.

The entire aircraft floated for some time after the crash, but only the central fuselage and the wings remained floating and were recovered immediately. Patrol boats from Palermo arrived 46 minutes after the ditching and began the rescue and recovery.

Passengers
One of the four crew members died—a flight attendant—and 15 out of the 35 passengers died. The engineer who died was not a part of the flight crew but had been called to the flight deck by the pilot and copilot after both engines failed; because he was not officially part of the crew, his death was accounted for as a passenger death. The flight's other flight attendant survived. All of the paying passengers were Italian, while the crew and the engineer were Tunisian. Autopsies indicated that many of the dead succumbed to the impact. Autopsies established that eight passengers who received injuries during the impact were unable to escape from the aircraft due to their injuries and ultimately drowned. Most of the survivors were seated in the rear of the ATR 72, while most of the passengers who died were in the front. Three dead passengers, including the engineer who tried to help the plane's crew, were found on the seabed. The ANSV stated that the cause of death of these passengers was difficult to determine.

Investigation
The investigation revealed several factors leading to the crash.
 * First, the investigation examined how the incorrect FQI came to be installed on the plane. The final report on the crash notes that during a flight the day prior to the incident, the Captain (who was also flying during the incident) became aware that the fuel quantity indicator (FQI) on the aircraft dashboard was not working correctly and reported the problem. That evening, the FQI was replaced, but with an FQI that was intended for the ATR 42, a different model of aircraft. The correct FQI was not found because its part number had been entered into the database in a different format than was searched for, and the inventory database mistakenly indicated that the ATR-42 part could be used on both models of aircraft. The FQI for the two aircraft models have different marking on the faceplate, though the difference was evidently not noticed.
 * Second, the investigation examined the fueling of the plane. The day of the incident, the aircraft was fueled for the flights from Tunis to Bari and Bari to Djerba based on calculations based on incorrect readings from the FQI. Because of differences in the shape of the fuel tanks, the incorrect FQI indicated a larger volume of fuel than the tanks actually held. When fueling the aircraft in Tunis, neither the refueling operator nor the flight engineer noticed the difference between the amount of fuel loaded and the change in reading on the FQI. The investigation also found that when departing from Tunis on the Tunis-Bari route taken before Flight 1153, the captain noticed by reading his cockpit displays that the aircraft's fuel level seemed to have increased overnight, but did not find a corresponding refueling slip. However, he accepted the explanation that the slip had been kept by a previous crew, though in fact the aircraft had not been flown nor refueled since the day before. Because the aircraft had been fueled for two flights, the flight from Tunis to Bari was uneventful. In Bari, the plane took additional fuel to a level where the incorrect indicator showed 2,700 kilograms. The correct indicator would have shown that there were just 540 kilograms in the tanks when departing for the Bari-Djerba route, insufficient to reach the destination.
 * Finally, the investigation examined the flight after the engines had failed. During an engine flame out crews must feather the propellers to reduce the drag on the blades so the plane can glide a further distance. While the propellers of the aircraft were found fully feathered after the crash, the crew did not feather them, because they were attempting to restart the engines. Furthermore, as a result of their efforts to restart the engines, the crew did not glide the aircraft at the optimum speed to extend gliding distance.

Simulation results suggest that handled optimally, the ATR could have reached Palermo with the tail wind of that day. Two crews flew a simulator at ATR's facility in France from the same starting conditions. By feathering the propellers and reducing the speed to the optimal gliding speed, one made a landing at Palermo and one ditched one mile short of the runway. The fundamental difference was that the simulator pilots knew what was happening and responded accordingly. In contrast, the Captain of the Tuninter ATR focused initially on trying to restart the engines in the hope they would respond, not knowing that this was impossible as his aircraft was out of fuel. When the engines could not be restarted, the Captain focused on selecting a place to ditch the aircraft. Unlike the simulator pilots, Gharbi had a lack of instruments and experienced radio interruptions. The final investigative report suggested that airlines train their pilots to deal with unusual situations.

Aftermath
Tuninter compensated each family of a victim or survivor with €20,000. On 7 September 2005 the Italian government banned Tuninter from flying into Italian airspace. Tuninter rebranded itself as Sevenair and had scheduled flights into Italy again as of 2007.

Criminal conviction
In March 2009, an Italian court sentenced the pilot, Chafik Garbi, to 10 years in jail for manslaughter. Prosecutors said that after the plane's engines stopped functioning, Garbi failed to follow emergency procedures, and that he could possibly have reached runway 25 of Palermo "Punta Raisi" Airport, or even the standard runway 20. Witnesses say he succumbed to panic and began praying out loud, rather than attempting to maneuver the plane to the nearest airport. The last five minutes of the cockpit voice recorder audio have a few scattered seconds of religiously oriented interjections such as "God save us!", with the pilot repeatedly telling ATC that the plane is too far out to make it to land, carefully selecting a ship to splash down near to, and repeatedly trying to restart the engines.'''

Six others, including the co-pilot as well as the Chief Operating Officer of Tuninter Airlines, were jailed for between eight and 10 years. They will not spend time in jail until the appeals process is completed.

Dramatization
The story of the disaster was featured on the seventh season of Canadian National Geographic Channel show Mayday (known as Air Emergency in the US, Mayday in Ireland and Air Crash Investigation in the UK and the rest of world). The episode is entitled "Falling Fast".