AF447

[mm43]

JD-EE,
Thanks! Notwithstanding your comments, I did generate -

Someone might like to comment on how effective the rudder would be in direct law at near stall speed pulling TOGA with only one engine. Remember, the BEA stated the vertical stabilizer damage showed the tail was rotating to port on impact and I couldn't help but wonder if only No.1 was operational.

and later I also remarked -

One and a half days after the impact the floating debris pattern would still have been relatively compact - say a radius of 0.5NM, as I construe the BEA's description of the impact as having little or no horizontal momentum - more a tail heavy "flat spin".

In the cruise, I assume the trim tank was in use - not helpful later on.

My supposition was that the a/c had had a 2 x flame-out at around 02:13:10z (loss of supply to the SATCOM) and the subsequent re-powering of the SATCOM at 02:13:40z was either on a restart of No.1 or the APU. A deep stall and high sink rate was already established, and the attitude could have resulted in the descriptions alluded to in the above quotes.

To put it bluntly, the crew/pax that were not belted in could well have compounded the maximum aft center of gravity problem.

The BEA's preliminary report provides -

02:14:14 - .1/WRN/WN0906010214 341036006MAINTENANCE STATUS ADR 2
02:14:20 - .1/FLR/FR0906010213 22833406AFS 1,,,,,,,FMGEC1(1CA1),INTERMITTENT
02:14:26 - .1/WRN/WN0906010214 213100206ADVISORY CABIN VERTICAL SPEED

These final 3 ACARS/ATSU/ACOM messages were probably initiated at 02:14:10z and their transmission time and sequencing provide for the reception times noted by the BEA. The Cabin Vertical Speed advisory tells me that passing through say 8,000 feet (various docs say 7350 or 9550ft) the a/c's vertical speed was in excess of 1,800 feet/min, or more succinctly that the cabin air pressure controllers ability to compensate had been exceeded, i.e. the cabin pressure was less than the external pressure. The earliest the CVS advisory could have been generated is 02:14:10z and the latest at 02:14:22z which provide descent/sink rates of 2,700 or 6,700 feet/min if impact is assumed at 02:14:30z. I have assumed a GS at impact of around 120KTS, which combined with the descent/sink rates mentioned of 2,700 feet/min (24KTS) or 6,700 feet/min (61KTS) is quite a substantial impact velocity. Put another way, the a/c's attitude was pitched up +10/15 degrees and on a glide slope (misnomer) of between 14 to 40 degrees.

The damage noted in various photos would probably support those speeds when combined with the impact square area and a/c mass, along with the resulting sequential break-up. In the case of the v/s the combination of the forward velocity and the tail yaw (to port) have obviously been used by the BEA in making their initial conclusion.

So in summary, the track flown from the Last Known Position at 0210z to the possible impact positions previously deduced could well have been direct and for about 1 minute prior to 02:14:30z the deep stall/high sink rate was established.

mm43