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To: expatpat
More details of the ACARS messages suggest following events while the airplane was in cruise (note, there is no message regarding electrics, hydraulics or engine problems):

02:10Z: Autothrust off Autopilot off FBW alternate law Rudder Travel Limiter Fault TCAS fault due to antenna fault Flight Envelope Computation warning All pitot static ports lost

02:11Z: Failure of all three ADIRUs Failure of gyros of ISIS (attitude information lost)

02:12Z: ADIRUs Air Data disagree

02:13Z: Flight Management, Guidance and Envelope Computer fault PRIM 1 fault SEC 1 fault

02:14Z: Cabin Pressure Controller fault (cabin vertical speed)

Not much doubt a stall occurred, either from too little speed or excessive attitude and over-correction.

There appears to be too little time for a low speed stall over-corrected by diving for speed to then over-speed and get airframe failure.

In the Qantas Airbus incident, the pilots decided that the aircraft had stalled and then over-speeded simultaneously, which commanded a negative G pushover followed by a pitch up, suddenly climbing 300 feet and then abruptly pitched nose down into a steep dive.

The maneuver exceeded the design certification of the airframe. Luckily the pilots regained control, many passengers injured. That's why I theorize that over-speeding may have been the original problem causing a loss of control cascade.

48 posted on 06/07/2009 6:40:37 AM PDT by gandalftb (An appeaser feeds a crocodile, hoping it will eat him last......)
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To: gandalftb

“02:10Z: Autothrust off Autopilot off FBW alternate law Rudder Travel Limiter Fault TCAS fault due to antenna fault ...”

The ‘alternate law’ rudder travel limiter fault suggests that the problems started in the rear.

Where is the antenna for the TCAS located? If you know.


50 posted on 06/07/2009 6:47:53 AM PDT by UCANSEE2 (The Last Boy Scout)
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To: gandalftb; expat
BTW this warning:

02:10Z: FBW alternate law Rudder Travel Limiter Fault

Is very troubling. If the the entire air data system and gyros were lost, as the fault messages indicate and that caused the rudders full travel.....

Tumbling, big trouble. Icing, turbulence, whatever, does not explain the loss of the internal gyros, maybe lighning, maybe.

51 posted on 06/07/2009 6:49:45 AM PDT by gandalftb (An appeaser feeds a crocodile, hoping it will eat him last......)
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To: gandalftb
That's why I theorize that over-speeding may have been the original problem causing a loss of control cascade.

If it went nose up due to over-speeding, and was hit by a 100mph updraft, it could have ripped the tail and/or wings off.

52 posted on 06/07/2009 6:50:51 AM PDT by UCANSEE2 (The Last Boy Scout)
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To: gandalftb
02:10Z:.....All pitot static ports lost

This is the key error message. Once this happened, they were doomed because the flight-control system is then not operational, and the pilot has no mechanical backup and no way to control the A/C. The flight control surfaces go nuts.......

Who knows what occurred here, but I think a stall is unlikely. If the computer 'sees' low speed from the dead pitot heads, it would probably lower the nose and a dive would occur, without a stall. After passing Vne, it would break up.

59 posted on 06/07/2009 10:14:12 AM PDT by expatpat
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