Gnat down at CarFest

[jim's brother]

In post 209, Courtney Mil has offered a clear analysis of the possible reasons for this sad accident.

There is a 14-year-old thread here which addresses the roll rate of the Gnat and the potential for inertial coupling, fin stress and disorientation. The maximum roll rate of the Gnat could easily be increased by the removal of Fuse 13. It would be useful if the moderators could bring this thread to the front of the forum, as it is locked and therefore I cannot.

We shall probably never know why the aircraft had a positive pitch input during the latter stages of the second roll. However, I had the great pleasure of flying the Gnat during my RAF training, and confirm that the roll-rate during a "twinkle" roll is very high, even with Fuse 13 in-situ. From memory - and I am sure I will be corrected if my 40-year memory fails me - the procedure was to raise the nose slightly above the horizon, quickly apply full aileron, then almost immediately cease rolling. It was so fast - and so easy! - that there was little potential for excessive nose-drop. However, there was great potential for disorientation to occur, and that potential would increase dramatically (a) when carrying out two consecutive rolls; (b) at low level; (c) with the added psychological stresses of leading a formation and flying at a public display; and (d) if one were not fully experienced and current on the aircraft.

There is a high probability that (d) - experience and currency - is the overriding factor in this case. The AAIB report sets out this pilot's comparatively shallow experience of (a) flying in general; (b) flying fast jets; (c) flying the Gnat; and (d) his poor currency. With this in mind, others have suggested that this pilot should not have allowed himself to carry out this display flight. However, his flying experience appears to have met all the rules and, I am sure that the pilot was absolutely certain that he was up to the job. After all, he had had the benefit of excellent RAF training prior to his medical retirement, and I would imagine that flying the Gnat was his way of replacing his dashed ambitions within the RAF, and good on him for that. But - we pilots sometimes believe that we are more competent than we really are, and it often takes someone else to tell us the truth. I've been there.

What was lacking here was (a) a proper chain of supervison; and (b) a system of rules for experience and currency that took into account (i) the skills required to fly a fast jet competently; (ii) the experience required to carry out aerobatics safely in a fast jet at low level; and (iii) the currency required to ensure that a pilot is both competent and safe on any particular day.

I quote Salad-Dodger above "I was at that CarFest with my family. I had no idea that a pilot with so little experience and recency on the aircraft would be allowed to fly a display such as that at an event with thousands of people attending. That there is a system that allowed that to happen beggars belief."

Yes, Salad-Dodger, you are right. When I organised RAF air shows back in the '80s, safety of the public was my major concern. I was happy to accept that the pilots flying at my displays were well-supervised and well-authorised for the event by either the RAF or the CAA. I knew that the RAF's supervision was to a very high standard, and the CAA's was entirely satisfactory for the Pitts Specials and similar civilian aircraft. However, with the advent of ex-military fast jets to the civilian flying display circuit, I would not wish to be a Display Director now - because, based purely on the current CAA rules for of supervision and authorisation, I would be unable to trust any civilian fast-jet to produce a display which would meet my standards for safety.

I would strongly suggest that the CAA should produce a brand new set of rules for the flying of ex-military fast jets by civilians at air displays. I am not suggesting a massaging of the old rules - what is required is for the CAA to go back to square one and produce a proper set of rules fit for purpose. If this results in a reduction in the number of vintage fast jets available for display, that's life.