A stricken plane suffered successive engine failures before crash landing near the A90, air accident investigators revealed today.

Eyewitnesses watched in horror as smoke billowed from the private aircraft before it came down in farmland next to the busy A90 dual carriageway near Stonehaven.

The pilot risked his life in the accident in April last year to bring the twin engine aircraft to a controlled skid through the muddy field – before emergency services arrived on scene.

The Air Accidents Investigation Branch (AAIB) said an examination of the aircraft revealed that pistons in each engine had suffered heat damage.

The AAIB report concluded: “Ultimately, it was not possible to establish why pistons in both engines had suffered virtually identical types of damage, although it is likely to have been a ‘common mode’ failure, which could include wrong fuel, incorrect mixture settings (running too lean) and existing damage arising from the use of incorrect oil in cold temperatures.”

The pilot of the small plane managed to avoid a disaster when he glided the aircraft down over the road and landed it on its belly in the mud on April 9 last year.

Eyewitnesses reported hearing a loud bang as the aircraft passed over the town of Stonehaven, heading from Wick to France.

They watched in horror as smoke came from the aircraft as it descended towards the busy A90 around rush hour.

The pilot had been on the second leg of a journey from Canada to deliver the eight-seater plane to its new owners in Thailand.

The pilot was put in a neck brace and taken to hospital for treatment having managed to initially walk away from the wreck of the Piper PA-31-350 Navajo Chieftain.

He was uninjured in the accident.