It was a sunny day in Bari, Italy. Airport workers were fueling an ATR-72-202. The ATR was scheduled to fly to to Djerba-Zarzis Airportin Djerba, Tunisia later that day. The 45-year-old Captain Chafik Al Gharbi (شفيقالغربي), a skilled and experienced pilot with a total of 7,182 flight hours came. The co-pilot, 28-year-old Ali Kebaier Al-Aswad (عليكبيّرالأسود) arrived a bit later. The co-pilot had logged 2,431 flight hours. Both the captain and co-pilot were well-acquainted with the ATR 72, having accrued 5,582 hours and 2,130 hours in it, respectively. After the pilots entered then the attendants and passengers also arrived. Shortly after that the plane took off without having any problems heading towards Djerba. The plane was was halfway to Djerba-Zarzis Airport and in the middle of the Mediterranean sea when the right engine suddenly stopped working. A little bit after the right engine stopped, the left engine also stopped working. The fuel gauge indicated that there was more than enough fuel for the flight. The pilots did not understand the reason for the engines shutting off. They were utterly bewildered. The co-pilot repeatedly tried to make the engines to go running again without success. Then there was silence in the passengers cabin because the engines stopped spinning and nobody said anything. The silence continued for over 16 minutes before the plane crashed into the water like a very big piece of aluminum crashes into concrete at high speed. The last moments the pilots were praying. The investigators found that not a very professional thing to do. At impact the plane broke into three pieces. 16 out of the 39 people aboard the plane did not survive the crash. Many of the passengers did not listen to the useful advice of the flight attendants. They had already blown up their life jackets before they even got out of the plane. The problem with blowing your life jacket before you leave the airplane is that you can get stuck while leaving the wreckage. Some of the passengers died just because they had had their life jackets blown by themselves or by someone else before the crash. The flight attendants tried to stop the passengers the passengers from inflating their life jackets. Some panicked and did not listen. The survivors grasped the wings and the middle piece of what once was the fuselage because they were the only large things left from the ATR-72 that actually floated and could be grasped by the survivors of the crash.
The investigators immediately asked themselves that if the plane’s tanks were really still full, why then did the wing float and not sink (the kerosene tanks in the ATR-72 are located in its wings). That did not per se mean anything; the pilots could have dropped the kerosene just before the crash to minimize impact. Because the tanks were ‘full’ and both of the engines stopped they first began to analyze the quality of the kerosene at Bari International Airport, where the plane was fueled. They also analyzed the quality of the kerosene of the airports where the airplane had been fueled previously. The kerosene at all of the airports was good. The quality of the kerosene was not the cause. After that they began to look at the maintenance done to the plane. They saw that the evening before the flight the fuel quantity indicator (short for FQI) replaced. They brought the wreckage on land. They searched for the FQI and they found it somewhere. After further inspection of the FQI it turned out that the FQI was made not for the ATR-72, but for the smaller version of the ATR-72, the ATR-42. Apparently the FQI of the ATR-42 showed a different value with the same amount of fuel than the FQI of the ATR-72. That means that the Airport workers fueled the plane with an inadequate amount of for the flight to Tunisia.
The pilots used their precious time to try to restart the engine instead of navigating the airplane to Palermo. If they had not closed their eyes and prayed to stay alive, they could have tried to make the impact less fatal. If they only were able to decrease the number of fatalities by one, then there would not only be one less family mourning, there would also be one less victim in aviation.
I think that it must have been a really bad experience for all of the 23 survivors because first they crashed, then saw other people drown and then they had to wait 46 minutes in the high saline Mediterranean sea with a lot of open wounds for help from patrol boats from Palermo, Sicily. I also think it is kind of strange that the FQI of the smaller ATR-42 fitted perfectly without any problems into the ATR-72. You could not differentiate between the two if you only looked at the size and shape of them.
Here you can read about the crash of this plane on Wikipedia.