Originally Posted by
Capt Scribble
The fact that the escape manoeuvre had not been practised or demonstrated is yet another red herring. It is not possible for an RAF QFI who taught aerobatics not to know what to do when a vertical manoevre goes wrong. The argument suggests that an experienced low-level aerobatic pilot did not have the knowledge, and possibly skill, to safely escape his predicament if he did not make the ‘gate’ at the top of the loop. Not possible and I would consider it wreckless to pull up for loop without that knowledge.
The RAF teaching for what to do when a vertical manoeuvre goes wrong is to close the throttle and centralise the stick and rudder pedals. That is not an appropriate recovery when a gate height is not achieved during a looping manoeuvre in a display.
Low speed light aircraft do not use a gate height during low level looping manoeuvres because it is not appropriate with the high pitch rate at the apex and the small radius. Therefore, rigid application of a gate height protocol will not be a familiar procedure for a display pilot whose experience is mainly light aircraft, however experienced he is.
I most certainly agree that a pilot who pulls up for a looping manoeuvre at a display and does not have a robust plan of what to do at any stage around the manoeuvre when the airspeed and height are insufficient to continue the manoeuvre safely is indeed being reckless.
Ridger,
The errors in the pull-up point are because there are many variables (airspeed, wind, angle off the display line, unfamiliar display site etc) and the pilot has to make a purely visual judgement, often with a very shallow sightline angle and, therefore, little plan view perspective. Therefore, it is easy to make a misjudgement. During the pull up more plan view is available aiding judgement and allowing for corrections to be planned. If the roll angle is not varied on the way up then a 'bend' can be used on the vertical down line to help regain positioning.
The pitch oscillations following a rapid change in angle of attack are (and you did ask!) caused by a low frequency and only moderately damped short period pitch oscillation, resulting from high pitch inertia and low angle of attack stability.
The '70% confidence' comment comes from something that I was told many years ago but I am afraid that I cannot remember the source. However, it is consistent with what I have observed in pilots over many years. The other ~30% is motor skills, hand-eye co-ordination etc. I will admit that this is not a real area of expertise for me and there are others far more knowledgeable than I am on this.