They also revealed the pilot attempted a desperate emergency landing just half a mile from his grassland airstrip.

Former RAF officer David Trueman, from Galashiels, was alone in his twin-seater Zenair Zodiac when it nose-dived into a gorse-covered and mist-shrouded hillside.

Experts from the Air Accident Investigation Branch (AAIB) have just published their report into the December 30 crash. They say it is possible that the single-engine yellow plane may have suffered icing to its carburettor which led to engine failure.

The inspectors found no major mechanic fault with the engine itself.

And they say there is evidence that the 65-year-old pilot realised he was in danger and started forced landing procedures – including switching off the fuel supply to the engine, a move which would minimise the risk of fire. It's likely he was flying almost blind using the plane's instruments.

Investigators say the plane hit the ground during a high-speed nose dive and that the crash was not survivable.

Mr Trueman, a former squadron leader with the RAF, had held a private pilot's licence since 1997, clocking up 310 hours – 130 of them in a Zenair Zodiac in the two years prior to his death.

Mr Trueman worked with the Ministry of Defence in Whitehall after leaving the RAF and moved to Borders in 1998. He lived at the Coach House, Glenmayne, and was survived by his wife Angela, daughters Alison and Caroline, stepdaughters Michele and Tanya, and stepson Mark.

Mr Trueman shared the grass runway at Midlem with fellow pilot Robin Johnstone, of Templehall Farm.

Mr Trueman and Angela were organisers of the Borders Vintage Automobile Club's annual rally at Thirlestane Castle and he was chairman and treasurer of the Scottish Borders Elder Voice.

The AAIB probe reveals that Mr Trueman checked the weather forecast on the Met Office website on the morning of the crash and told his family he intended to take a short local flight.

Investigators obtained an afterforecast which revealed that when Mr Trueman took off around noon there was an occluded front – cold overtaking warm – running north-south and moving east across the Borders. Investigators learned the weather started to close in shortly after Mr Trueman took off, leading to patchy hill fog which may have reduced visibility to around 200 metres. The cloudbase was low and it was drizzling.

Evidence shows the plane came down around an hour after taking to the uncontrolled airspace around Midlem.