The co-pilot of an RAF passenger jet which suddenly went into a dive after the captain allegedly lost control has told a court martial he thought he was going to die as the aircraft plunged towards the Black Sea.
Flight Lieutenant Nathan Jones had left the cockpit to make a cup of tea when the Voyager plane, with nearly 200 service personnel on board, plummeted 4,400ft (1,341m) in a matter of seconds - throwing him on to the ceiling.
Flt Lt Jones told the court martial in Bulford, Wiltshire, that he was able to crawl back into the cockpit of the aircraft where the captain, Flight Lieutenant Andrew Townshend, was battling to regain control.
It is alleged that a digital camera Flt Lt Townshend had been using in the cockpit to take pictures jammed the flight controls causing the autopilot to disengage and the plane to nosedive.
Flt Lt Townshend, 49, is accused of lying in both a technical log and service inquiry and insisted the incident had been caused by a technical fault.
He denies two counts of perjury and making a false record in relation to lying but admits negligently performing a duty in relation to the camera colliding with the aircraft's control stick.
The court heard that the incident took place over the Black Sea during a flight from RAF Brize Norton to Camp Bastion in Afghanistan on February 9 2014.
Flt Lt Jones said he had flown with the defendant "many times" and regarded him as a good friend and colleague.
He said that during the flight, Flt Lt Townshend had been taking photographs on his Nikon digital camera of other aircraft passing by.
After leaving the cockpit, Flt Lt Jones described what he thought was turbulence but then heard the "cavalry charge" alarm sound.
"It felt like a rumble, a bit of turbulence and suddenly everything hit the roof," he told the seven man court martial board.
"It was pretty sudden. But when you are pinned to the roof you know it is something to do with the aircraft.
"I remember there being lots of sounds and I remember it felt like a rush of wind from the outside of the aircraft. It was really noisy.
"It is very hard for me three years later to being able to say... it was very traumatic. It was the worst experience of my life. I thought it was curtains."
The witness said he crawled along the ceiling of the plane back into the cockpit.
"When I got into the cockpit that was when it went suddenly pitch black and you could see we were going into the sea or something very dark," he said.
"There was a lot of flashing lights and everything was stuck to the ceiling and Flt Lt Townshend was shouting that he couldn't get the autopilot out.
"I knew we were over the Black Sea so that was what I imagined in that split-second.
"I can remember him saying 'Get back into your seat I can't get the autopilot out'."
Flt Lt Jones said he was "acutely aware" of the risks of pulling back on the controls too heavily as it was possible to snap the aircraft's wings.
"I was grappling with the controls trying to get it out of the dive and pressing the (autopilot) disconnect on my side," he said.
"I could feel the aircraft pulling out of the dive and that's when it suddenly went from negative G to positive G and being pulled into my seat the wrong way.
"As far as I was aware Flt Lt Townshend was trying to do the same thing. He was still strapped in so wasn't on the ceiling but I imagine he would have been pretty stuck on his anti-G strap."
Flt Lt Jones said he was not able to say whether the autopilot was on or off when the incident happened as he was not in the cockpit but afterwards was trying to work out what may have happened.
"I was trying to diagnose what happened," he said.
"As far as I was concerned the autopilot was still 'in' and there had been some sort of autopilot malfunction.
"When you put the autopilot back 'in' and levelled it was a perfectly functioning aircraft. It was very confusing.
"The only thing that we could think of was that there was an autopilot malfunction. It was so bizarre because no faults came up."
The witness said he asked Flt Lt Townshend about what happened and he replied: "Nothing, I was just looking out of the window, looking at the stars."
The court heard Flt Lt Jones suffered fractures to his back, a prolapsed disc and nerve damage and underwent surgery. It was more than two years before he flew a plane again.
The court martial board also heard audio recordings taken from the cockpit voice recorder of the incident.
The cavalry charge alarm starts beeping and Flt Lt Townshend can be heard telling Flt Lt Jones "get in the seat".
He adds: "I can't get the AP (autopilot) out, can't get the AP out. I can't, I can't ..."
"Holy s***, I've got it, I've got it. Get a Mayday call out."
There is a lot of heavy breathing and Flt Lt Townshend can be later heard saying: "F****** hell, holy s***. What the f*** just happened?"
Flt Lt Townshend then addresses the passengers over the intercom telling them that he did not know what happened but advises them to remain buckled into their seats.