Air France (F-GITA) Accident Tahiti (1993)
This is an old accident, but I am researching to discover at what point the software logic was changed on the B744 with regard to the sine qua non of this accident.
At the time of the accident, if the autothrottles were left engaged as you crossed over the MAP (E/D) on a VNAV approach, the FMA logic would shift to THR REF||VNAV SPD and the power levers would surge forward to do an "automatic go-around" of sorts. The Air France FO manually overrode the throttles, but after touchdown, when he went to reverse, the throttles started forward again and he missed the #1 reverser, allowing the #1 engine to be at go-around thrust while the other three were in reverse. They ended up in a lagoon off the right side of the runway.
Somewhere along the line, Boeing must have changed this logic because the Boeing Flight Crew Training Manual now states that on a VNAV approach, "VNAV path guidance transitions to level flight once the missed approach fix is passed." FCT 747 p.5.48 (June 30, 2015).
I can find nothing in any manual that discusses this automatic go-around feature. I suspect Boeing realized this was a bad idea, so at some point after the accident they revised the software. I just don't know when. Can anyone point me to any documentation (memos, bulletins, etc.) that would shed more light on when the changes were made? Thanks.
Last edited by cf6-80c2b5f; 20th Aug 2016 at 01:37.