Although the Airbus A300-600F, which struck terrain while attempting to land at Birmingham(BHM/KBHM), had been fitted with an approved Honeywell warning system, it did not feature the most recent available software.
If the software on the jet had been updated the aircraft would have entered the terrain alert envelope about 200ft above the ground, some 1.3nm from the runway threshold.
The crew of the A300 received a ‘sink rate’ warning about 8s before an initial collision with trees, with a ‘too low, terrain’ caution sounding just after the strike.
In a special bulletin dated 13 March the US FAA states that the latest software would have provided a ‘too low, terrain’ alert some 6.5s earlier, when the aircraft was 150ft higher.
“Although it is not clear if the later version of the software would have prevented the accident, it would have provided a significantly improved margin of safety,” it adds.
The bulletin, which has also been highlighted by the European Aviation Safety Agency, has not been elevated to a formal airworthiness directive.
US National Transportation Safety Board investigators pointed out that the A300’s high descent rate would nevertheless have “compromised” the effectiveness of the warning system, even with the updated software.
But their analysis of the August 2013 crash determined that an immediate activation of the go-around switch, or an aggressive manual response to the terrain alert, would have enabled the aircraft to avoid the impact.
(David Kaminski-Morrow - Flightglobal News)