I did a board of Inquiry at Tengah on a Lightning that had caught fire on the ground after startup. The cause was that an overwing vent valve had failed. When the engine started, the AC came on line, the ventral tank started feeding and the failed vent on the wing allowed the fuel to vent over the wing and the fuselage. Sods law says that if you pour enough fuel over a Lightning with an engine running it will catch fire; and so it did. The aircraft had a history of venting fuel. This I found out because being an ex tanker pilot I had a look at the detached Victor KC1's fuel logs which showed that this aircraft has taken disproportionately more fuel than the others.
Our recomendation to prevent a reoccurrence was to advise that the ventral tank should not be switched on until the take off point. This was accepted and put into place by the powers that be. It would be pertinant to point out that I, the other GD pilot, and the Engineering officer on the Board of Inquiry had no direct knowledge of Lightnings but we were General List GD and Engineering officers so therebye qualified. There was also no objection from the hierarchy of Tengah.
A few months later somebody gave his 8mm movie camera to a fellow pilot and asked him to film a double reheat take off with a vertical climb. The aircraft hurled down the runway, lifted off and at around 250knots was rotated into the climb. It G stalled, autorotated into a Kampong killing the pilot and one or two on the ground.
For the B of I it was easy; the had a film of the whole thing. It transpired, with Boscombe Down's help that with a full or nearly full ventral tank the aircraft's C of G was on or aft of the limit, something not experienced before because the ventral was a third empty by the time the wheels came off.
A little knowledge can be dangerous. The B of I, in retrospect, should have been carried out be Lightning friendly members. However, in this case there were no operational issues involved so anybody could do it.
Do I feel guilty? No; I had forgotton about it until now.