PPRuNe Forums - View Single Post - AF447
Thread: AF447
View Single Post
Old 12th Jun 2009, 00:38
  #1216 (permalink)  
WhyIsThereAir
 
Join Date: Jun 2009
Location: LA
Age: 69
Posts: 50
> One can determine that the vs was fixed in place due to a complete lack of real time messages relating to a whole range of other systems that would shout fault immediately.

One can determine the VS was in place during the time the messages were sent by a far simpler test: the messages were received. Talking to a satellite requires a moderately stable platform. There are slew limits on how fast the antenna can track, even if it is a patch antenna or electrically steered antenna. The antenna has both pitch and roll limits and pitch and roll rate limits. It may also have limits on altitude change rate.

Mental excercise 1: Take a craft in stable level flight under AP. Remove the VS. What will happen? How long will it take to happen?

Mental excercise 2: Take a craft in 'strong turbulance' in alternate law with no airspeed indication and no visual clues, being hand-flown reasonably stably. Remove the VS. What will happen? How long will it take to happen?

I submit that we KNOW the VS was present and functional at 02:14. We know this because messages were sent (and received) that were timestamped at 02:14. They would not have been able to be sent (or at least received by the satellite) if the craft had not been reasonably stable in reasonably level flight.

We do not know what happened after 02:14.
WhyIsThereAir is offline