PPRuNe Forums - View Single Post - AF 447 Thread No. 12
View Single Post
Old 12th Jun 2014, 18:41
  #81 (permalink)  
angelorange
 
Join Date: Dec 2002
Location: Europa
Posts: 612
Likes: 0
Received 0 Likes on 0 Posts
Bonin pulled the A330 into a fully developed stall

DozyWB - you make some good points and I agree both Airbus and Boeing have gone some way to educate the flying public on correct AoA reduction techniques. Flight testing FAR/JAR25 demands AoA reduction then 20% above stall speed before adding power.

Low alt, approach to stall min height loss recovery was stressed by FAA and CAA examiners for PPL and Commercial pilots - it instilled the wrong message at the foundational stage of flight training. In aircraft with underslung engines or tractor propellors adding thrust adds to the pitch up moment (not so much at high altitude grant you). Slowing down also activates aft pitch trim (AF447 A330 had maximum aft tailplane trim) which makes recovery even more difficult as the Thomsonfly Bournemouth stall episode revealed: Air Accidents Investigation: 3/2009 G-THOF

The Airbus get out of jail free option (Windshear, Terrain, Woop Woop pull up, etc) was regularly emphasized for LST/Initial Type Rating training - essentially (in normal/non degraded mode) it allows you to get to the light buffet (Cl max) with maximum thrust and no stall. It requires Full Aft stick and TOGA. What did Bonin consistently do in the confusion? The BEA have a video of the flight recorders that has not been on general release - it shows the side stick positions on both sides - the FO also applied aft inputs (his seat was found wound aft at the sea bed).

Bonin was spooked long before the fatal events - read his reaction to the smell of ozone. But his techniques and both pilot's ignoring a stall warner speak of poor training and poor understanding of the situation their reactions had created.

Have you discovered how much gliding Bonin had done and how long it had been since he stalled a glider? The BEA AF447 investigator at a recent RAeS Upset recovery lecture did not consider his glider training to have been very frequent or recent to events.

Apparently the junior crew had practiced unreliable airspeed some time before AF447 and the SIM route was from Rio with drifting ADIRUs.
angelorange is offline