PPRuNe Forums - View Single Post - Big Crash at Reno
View Single Post
Old 18th Sep 2011, 11:43
  #80 (permalink)  
Pilot DAR
Moderator
 
Join Date: Aug 2006
Location: Ontario, Canada
Age: 63
Posts: 5,620
Received 63 Likes on 44 Posts
100 percent agreed, and the TT failure was the result of a high-speed stall and buffeting. To say the pilot is to blame is an understatement.
Huh? Would deSitter please decode this?

In general, a high speed stall (among other factors) could cause buffet, which is quite different from flutter. That buffet could, and should act upon the leading edge of the H stab to give the pilot a warning of impending stall. It is unlikely in the extreme that the buffet would affect the elevator trim tab in any meaningful way.

Flutter of a trim tab could occur from a combination of circumstances, which would generally include none to only light aerodynamic forces on the tab and high speed, and a combination of other factors, which could be design, construction, or maintenance (but not piloting) related. A larger aerodynamic load (like high G - piloting) on the tab would tend to prevent flutter.

A high speed stall will occur when a combination of increasing G and decreasing speed causes the critical angle of attack to be exceeded, and the wing stalls. A stalling wing is associated with rapid deceleration, which is the best thing to stop flutter. To get the increasing G, a lot of pitch control force is being applied. This control force input is likely to also assure that trim tab flutter does not begin.

High G and/or high speed stall will not cause flutter, or buffet which would harmfully affect a trim tab.

Flutter of a trim tab, caused either by poor flutter resistance at high speed (design), or failure (construction/maintenance) could very certainly cause a loss of control and high G, which the pilot could not overcome (so not piloting).

Having no more information than the photos and videos I have seen here, it certainly does not appear to me that a high speed stall occurred, though there does appear to have been a trim tab position problem.
Pilot DAR is online now