[Flyboy]

Actually, his license hadn't expired, it was dated until December nineteen seventy-five. It was his IMC rating that was out of date. This was an apparent oversight and administration error, rather than his competency. He was rated in the US for IMC, but he mistakenly assumed that, as he renewed the rating in Canada in nineteen seventy-four, it would have been accepted in the UK, as it was in the US. This is in addition to the fact that the aircraft's country of registration was not clear. The previous owners had de-registered the aircraft in the USA and had not re-registered the aircraft in another country. As the rules sate that the pilot flying an aircraft registered in a different country, he must be rated in the UK. However, he had logged over one thousand six hundred hours as captain, with more than one thousand hours on type; more specifically, in the aircraft flown. He had in excess of one hundred and fifty hours on instrument and eighty hours at night; including over thirty landings in conditions.

It was assumed, initially, it was instrument failure that was the root cause, but this was discounted by the AAIB report from the investigation into the accident. His RT was malfunctioning though and he had been out of radio contact for some time during the flight. The inexperience and lack of training of the local ATC at Elstree, in my opinion, could have been a contributing factor. They were not trained in IMC nor night operations and were unlicensed (not necessarily required for private fields). It is possible that they gave conflicting instructions as to the QNH/QFE (altimeter calibrations) at Elstree. But I think the more likely explanation was the VOR station at Lambourne was to blame. It had been having some calibration errors at the time and could have given incorrect information, leading to inaccurate range and vectoring data.

But it appears that the AAIB gave pilot error as the cause of the accident.