A helicopter which crashed in Afghanistan causing unsurvivable injuries to two British air force officers was unable to land on a football pitch because there were players on it, an inquest has heard.

Flight Lieutenants Alan Scott and Geraint "Roly" Roberts died after a Puma Mk 2 helicopter crashed while trying to land at Nato's Resolute Support mission headquarters in the Afghan capital Kabul on October 11 2015.

They were among the five people killed, who also included 44-year-old French-born security worker Gordon Emin and two US personnel, while five others were injured.

An inquest into their deaths at Oxford Coroner's Court on Monday heard how 32-year-old Flt Lt Scott died as a result of "multiple injuries including a closed head injury" which were "not survivable".

Flt Lt Roberts, 44, from North Wales died from a "blunt force head injury", which forensic pathologist Dr Nicholas Hunt said in the post-mortem report would have caused him to become "deeply unconscious and effectively dead".

The cause of death for Mr Emin, who lived in Kabul and whose inquest was also opened, was given as a spinal fracture.

A service inquiry report into the incident, published in December last year, said the helicopter that the crew and passengers were in struck the tether of a nearby surveillance balloon after being forced to re-circle the pitch.

Sergeant Simon Craig, who was flying as a crewman in the lead Puma helicopter, in formation and in front of the other as they neared the landing site, said he expected the players on the pitch to move, but that they did not.

"On the approach I realised at the late stage there were a number of players on the pitch.

"We had to overshoot to the east as we were unable to land on the field until it had been cleared," he said in a statement read in court.

During his evidence he told the inquest that they had landed on the field 30-40 times before, and that "overshooting is standard practice if the landing site is unsuitable".

Sgt Craig said they had been told about the balloon, also called a persistent threat detection system (PTDS), and to "look out for it", but stressed that the cable it was attached to was difficult to see despite the attached orange flags.

Giving evidence, Flt Lt Karim Zid, a pilot in the lead Puma helicopter, also stressed how the balloon could be difficult to spot, that it was something they had to work around, but from an operations perspective was there for an invaluable reason.

Within his statement Flt Lt Zid said he saw 20 people in football shirts and shorts playing football on the pitch as they attempted to land, but the safest option was for the field to be cleared before touching down.

He said the other Puma should have followed them into the overshoot turn, adding: "There was no reason for them not to follow us into it."

Witnessing the helicopter "not flying in a controlled way" once he could see it again, Flt Lt Zid said when it crashed to the ground he knew it was a significant incident with fatalities.

Lead captain of the two helicopters Flt Lt Michael Richards, who was also the pilot in control of first Puma, told the inquest that on the manoeuvre out to wait for the pitch to clear, Sgt Craig said over the radio the other helicopter was making an approach to land.

Flt Lt Richards said he thought it was "not correct for him to make an approach before me", but added: "No more than five seconds later Sgt Craig said they had a tail rotor failure."

He told the inquest this was the worst case emergency and that he watched the helicopter crash towards the ground.

Both Flt Lt Richards and Flt Lt Zid, along with Sgt Craig, told the court they have all completed subsequent deployments in Kabul, and noted how procedures surrounding the balloon have changed, and that the pitch is still used for football and landings.

Flt Lt Scott and Flt Lt Roberts were members of the Puma helicopter force based at RAF Benson in Oxfordshire. The helicopter crashed at a road junction within the headquarters compound at around 4.15pm.

The inquest into their deaths is expected to continue until Thursday.