Tony Collins's IT Projects Blog

The last few minutes in the cockpit of two Boeing 757s were spent in fatal confusion.

The computer-driven displays were warning the pilots they were flying too fast and too slow. Too fast and the airframe could break up. Too slow and the aircraft could stall. 

What could the pilots do?  

Articles in Computer Weekly in June looked at the loss of the Air France Airbus A330-200 in comparison with two much earlier accidents.

French authorities have said there were indications that the pitot tubes on the Airbus might have been blocked, causing the onboard systems to give the pilots conflicting information about their air speed.

After two Boeing 757s went into the sea in 1996, with the loss of 259 lives, investigators discovered that the onboard systems had given the pilots conflicting information about their air speed because of blocked pitot-static systems.

Last week's press conference on the loss of the AF447 Air France Airbus A330-200 highlighted the importance of black boxes in any major fatal crash investigation.

Spokespeople for BEA, the French air accident investigators, were at the conference to report their interim findings. Without the cockpit voice and flight data recorders they don't know why the Airbus went into the Atlantic Ocean off Brazil on 1 June.

They still hope to find the cockpit voice and flight data recorders, although hopes of finding them before they are damaged by salt water, are fading.  

There's an extraordinary contrast in the [separate] investigations into the causes of the Airbus and Chinook crashes. In one, accident investigators admit they don't know what happened because there are no black boxes.

In the other, the MoD and two air marshals said the pilots caused the crash although the helicopter wasn't fitted with black boxes. Chinook ZD576 went into the Mull of Kintyre in June 1994, killing all 29 on board, including 25 VIPs.

The MoD and the air marshals didn't simply blame the pilots: they found them grossly negligent. RAF rules at the time said that deceased aircrew could be found negligent only if there was "absolutely no doubt whatsoever".