Test pilot tells inquest when he realised his navigator had fallen out the plane

A test pilot told an inquest he heard an explosion as he was flying a military jet upside down at around 450mph, then realised that his navigator had fallen out.

Former RAF fighter pilot Mark Williams, 50, said he looked in the mirrors of the RAF Tornado to check on colleague Michael Harland but saw 'nothing'.

Mr Williams was flying the warplane at around 5,000 feet above Norfolk on November 14, 2007 when Mr Harland fell to his death while strapped in his seat.

The inquest at Sprowston Manor Hotel, near Norwich, has heard that Mr Harland's ejection seat had not been properly fitted.

Jurors have heard that the seat struck the fin of the Tornado GR4, causing damage which would have prevented either of the two parachutes from working.

Father-of-two Mr Harland, 44, also a former RAF flyer who had been working as a civilian navigator, suffered multiple injuries and his body was found in a field near North Barsham, near Wells.

The inquest has been told that Mr Williams and Mr Harland, who both worked for BAE Systems, which services Tornados based at RAF Marham, had flown from the airbase to test the two-seater fighter jet after a lengthy service which included the fitting of new parachutes.

Mr Williams landed the damaged plane safely after making a distress call and was unhurt.

Mr Williams said he and Mr Harland were in the latter stages of the 90-minute test flight. He said the accident happened about 'half a second' after he 'inverted' the jet.

'There was a loud explosion,' said Mr Williams, who joined the RAF in 1978.

'The air in the cockpit became mist. When I opened my eyes, I saw the mist was also filled with yellow debris, like loft insulation, which was rushing around the cockpit. There were also several bits of paper.'

Mr Williams said he slowed, lost height and turned the plane the right way up, then checked on his 'friend and colleague'.

'I looked in my mirrors and I saw nothing,' he told inquest jurors. 'I could see right the way back to the rear bulkhead.'

He added: 'Once I realised he had gone, I turned the aircraft around straightaway to look for a parachute.'

Mr Williams said he made a distress call, alerted rescue helicopters and asked for another jet to fly alongside the Tornado and check the damage.

The inquest also heard that military flyers were not fully checking a seat-locking mechanism designed to stop pilots and navigators falling from RAF Tornado GR4s flying upside down.

Many RAF and civilian test pilots did not realise that there were two parts to a pre-flight safety check on the device, Jacqueline Lake, deputy coroner for Norfolk was told.

Mr Williams, who lives near Grantham, Lincolnshire, told the inquest he had been under the impression that he should conduct a check on one part of the locking device – not on two parts.

Accident investigator Stephen Moss has told jurors that the 'misengagement' of a locking device, which prevented the seat from sliding when the jet flew upside down, was the 'most probable cause' of the accident.

An RAF Board of Inquiry concluded the cause of the accident was 'the incorrect engagement of the seat-locking mechanism on installation of the seat to the aircraft'.

Mr Harland was married with two children and lived in Colsterworth, near Grantham in Lincolnshire.

The inquest continues.