Tuninter ATR-72 Crash on 06 Aug 2005?

Question

How many of you were aware that the recordings from the block box of the Tuninter ATR-72 Crash on 06 Aug 2005 were leaked out? Have you heard it, and what is your reaction to it?

http://blog.360.yahoo.com/blog-5ksVjU47eqs_12qDwPwirmLXqHA-?cq=1&p=1860

Investigators have revealed that, immediately before the fatal flight, the aircraft had performed a Tunis-Bari service and landed at Bari in Italy with just 305kg of fuel in total – a level which should have triggered a low-fuel alert to the crew. But the gauge incorrectly indicated that the ATR72’s tanks contained 2,300kg. This was because the ATR72’s fuel warning system depended on the information from the fuel-quantity indicator, an indicator which was reading incorrectly because it was designed to be fitted only in a smaller plane: the ATR42. The aircraft subsequently took on just 265kg of fuel at Bari, departing for Djerba with only 570kg in total, but which showed as 2,700kg to the crew. During the flight, no low fuel warning has triggered, due to the wrong indicator. The turboprop suffered fuel exhaustion and the ATR72 ditched off the Sicilian coast. Among the 39 (passengers:34 crew:5) onboard, 14 were killed, including 2 crew.

Answer 1

I didn't know about black box, but however it was quite clear since the first hours....when i saw the first images on TG(news, in Italy "TeleGiornale") i said my mum: "I think it finished fuel in flight, probably because of a malfunction of fuel indicator during refueling". I thought this because I heard about some similar cases in university lessons(I study aerospace engineering), and because wings were floating too much, as they had not to do because of the 2 engines if they were not empty(the plane was about half way between Bari and Tunisia, not far from Palermo, so tanks didn't have to be empty)
And pilot did an incredible good work because without working engines airliners are not easy to be controlled because elevator,ailerons,rudder...are all driven by hydrodynamic system, and pressure(or more properly power) to hydrodynamic systems is provided by engines, no engines mean no pressure in the system and so the plane is not controllable.
In this case pilots were not as lucky as the Gimli Glider(they were on land and landed on an abandoned airport used as go-kart circuit) but they did what was possible.We can say that they did not lost 14 lifes, they saved 25 lifes.

For QAssurance:
1) hydrodynamic system is a synonymous of hydraulic system.
2)OK, you are right, in the specific case of ATR elevaror,ailerons,rudder are not hydraulic, but seems quite strange that control surfaces are directly linked to the stick by cables(I found a file that sais "mechanically actuated and controlled", and why install a stick shaker, that is typical of servo-assisted flight controls?), how can the autopilot act if the controls are full-manual?(and the ATR has autopilot on 3 axes......all except auto-throttle)
And ATR has 2 indipendent hydraulic systems anyway...
Control on Roll axis is helped by hydraulic powered spoilers, they act when ailerons are deflected more than 2,5 degrees. So it's quite correct to say that a malfunction to hydraulic system affects maneuvrability....

Answer 2

OK someone said something about "hydronamic" power to flight controls. On an ATR-72 all flight controls are powered by cables except for flaps. There is no such system in any airplane called hydronamics. Hydraulics, aerodynamic (such as servo-tabs) and other such ideas, but the ATR's systems are much simpler than those in a large jetliner such as a 747 which has 4 separate hydraulic systems which power various parts of flight controls, steering, landing gear etc.

The comment about poor maintenance records is true, although it's unclear from any black box recordings whether it was actual maintenance that caused the problem or poor servicing, which is not considered maintenance. When someones fuels an airplane such as a regional turboprop, it is not normally done by a mechanic, and no logbook entry is required nor made. A small fuel slip is usually handed to someone in the flight crew at some point, and they verify the load with their fuel gauges once onboard. The fuel indication systems on most airplanes (except older GA airplanes) are pretty complex, pretty accurate and pretty reliable (although I realize complex AND reliable are sometimes at odds with each other).

So... when the engines quit on an ATR-72, due to high wing loading and the higher speeds needed to keep it aloft, the glide ratio is pretty poor compared to many other planes. You therefore need to put it into a relatively steep dive to prevent the wing from stalling. This sacrifices altitude at a rapid rate, and of course if you are over the water at the same time, the only last-second thing the pilot can do is try to keep enough speed until the end to flare for a slower, and hopefully softer, landing on the water. However, anyone who has ever belly-flopped knows how hard water can become when hit in the wrong way. Airplanes tend to break up when they hit something solid. Bummer.

It was certainly an unfortunate incident, and something we all hope the industry learns from.

Answer 3

Sad stuff. Poor maintenance and record keeping is a btch and death is sometimes the results. I feel bad for airline pilots as they don't have the luxury of the rest of us to open the cap to the fuel tank and actually verify wet tanks.

Answer 4

Tuninter