This article was posted to computer.risks recently.
Date: Tue, 04 Jul 2006 13:17:36 +0200
From: Peter B. Ladkin
Subject: B747 freighter crash
The Canadian TSB have issued the report on the 14 October 2004 crash of a Boeing B747 freighter on takeoff at Halifax airport, Nova Scotia.
According to a Flight International report by David Kaminski-Morrow (4-10 July 2006, p4), the TSB "says that the crew's misunderstanding of a laptop computer tool for calculating take-off performance led to the accidents. It concludes that the crew unwittingly transferred and used weight data from the aircraft's previous flight while calculating performance criteria for the next take-off. The obsolete data misled the crew to derive incorrect thrust settings and critical speeds for take-off."
The aircraft failed to lift off after rotation and overran the end of the runway by 250 meters, briefly lifting off but then striking an earth berm, severing the tail section and bringing the aircraft to earth again. All seven crew were killed.
I was deeply moved reading this. If it isn't already evident, piloting a 747 is not just a question of jockeying the thing down to the end of the runway and hitting the juice. So you put your faith in the numbers cranked out by a computer program since there are too many parameters for a person to take into account and deal with, and no-one has the numeracy skills any more to realise that things might be a little out of whack.
I wonder if the crew had a gut feeling of the unfolding events, based only on the note of the jet engines and feeling of acceleration. No doubt they knew something was amiss when the damned machine refused to haul itself into the sky at the expected time.
My heart goes out to the families left behind.