PPRuNe Forums - View Single Post - AF 447 Search to resume (part2)
View Single Post
Old 26th May 2011 | 22:31
  #2498 (permalink)  
Lonewolf_50
Community Builder
Community Influencer
 
Joined: Aug 2009
: Military
Posts: 9,328
Likes: 2,175
From: Texas
From about two years ago, from poster snaproll3480
According to the QRH and based on a weight around 210t:
(speeds are approximate)

Green Dot (minimum clean speed): 245 kts

Turbulence penetration speed: 260 kts

Vls w/ 0.3g buffett margin: 235 kts

Speeds are all indicated so no ISA deviation necessary.
HN39

Thanks for the detail, HazelNuts, yet again I doff my cap.

In re the pitch down versus pitch up.

With the above airspeed limits in mind, how benign do you think an unexpected ten degree nose down pitch is while on IMC, and possibly in turbulent air, with those limits considered?

NOTE: this is not a declaration nor an assertion that such is what happened with AF 447, but an inquiry regarding, as a pilot, your tolerance for a sudden ten degree nose down event. The closest thing like it from my own experience was a runaway nose trim event (which was a bugger, but manageable) but that was not on a FBW aircraft, so my personal points of reference are vague at best.
I will refer to AMF's comments on upset response from about the time AF 447 went down, which sentiment seems to not be confined to him.
Originally Posted by AMF
The fact is, most pilots train for unusual attitude recovery where the recovery is accomplished in benign conditions with all flight controls working normally, a full panel, not to mention the engines running and outside visual reference. Many places don't even give "jet upset" training...i.e. loss of aerodynamic control at high altitude.

And a real-world jet upset, let alone sever or extreme turbulence involving all the forces, cannot be rendered or trained well in a simulator because the test pilots during certification don't even put the aircraft through those paces.
Also something that caught my eye ... http://www.pprune.org/rumours-news/3...ml#post4972892

Regards

LW50

Last edited by Lonewolf_50; 26th May 2011 at 22:45.
Lonewolf_50 is offline