PPRuNe Forums - View Single Post - AF 447 Search to resume (part2)
View Single Post
Old 14th May 2011, 19:12
  #1342 (permalink)  
mm43
 
Join Date: Jun 2009
Location: NNW of Antipodes
Age: 81
Posts: 1,330
Received 0 Likes on 0 Posts
HN39;
It is the fuselage violently veering to the right which 'twists' the frames.
I had refrained from making a comment, following your much earlier post where you considered the bank was to starboard rather than my posited port. The reason for my delay centers around the term "yaw" and its interpretation when related to the BEA's use of it in the end of flight events.

My interpretation was that the term "yaw" was being used to describe the aircraft rotating clockwise in a near horizontal plane about a fulcrum nominally near its CoG while airborne - (spin?).

Your interpretation (I believe), is that the "yaw" was introduced by the #2 engine digging in and creating the "tail yawing to port" event which resulted in the damage described and allowed the safe departure of the Vertical Stabilizer as the empennage dug deep into the water - probably collapsing and shearing off at the aft pressure bulkhead. The high CoG of the V/S and its own inertia then completed its final disengagement, allowing it to flop into the water on its port side. The APU, having being punched from its mounts gave a glancing blow to the rudder (as it swung hard to port following the loss of the hydraulics), then commenced its journey to the bottom.

I can go along with the above, but when introducing the "en ligne de vol" business plus the high RoD, the time between #2, the tail and #1 digging in, was in the order of milliseconds. Not enough time to overcome the moment of inertia already committed to the "en ligne de vol". As an after thought, and to just muddy the waters some more; - if the horizontal component of the aircraft's trajectory was say 30° to port of the "heading" at time of impact, the same damage would most likely occur.

It is rather academic at this time, but the actual rationale used by the BEA in making their interim conclusions would be interesting to know.

Last edited by mm43; 14th May 2011 at 21:26. Reason: spelling!
mm43 is offline