The manufacturers of an ejection seat which activated during a pre-flight check, throwing a Red Arrows pilot to his death, has admitted a breach of health and safety regulations.
The charge followed an incident in November 2011 when Flt Lt Sean Cunningham,35, was thrown 300 feet into the air after the ejection seat unexpectedly activated.
Martin-Baker Aircraft Company Ltd had previously entered a not guilty plea to a charge that on or before November 8, 2011, it failed to conduct its undertaking in relation to the design, manufacture, supply and support of the Mark 10b ejection seat in a way that did not expose non-employees, including Flt Lt Cunningham, to risk.
The charge particularised the non-deployment of the main parachute attached to the ejection seat during low speed or zero-zero ejections as a risk.
Ahead of the start of a five-week trial at Lincoln Crown Court, John Martin, a director acting on behalf of the company, entered a guilty plea as members of Flt Lt Cunningham's family sat in court.
The prosecution, brought by the Health & Safety Executive, arose out of investigations into the death of Flt Lt Cunningham. He was carrying out pre-flight checks on his Hawk jet at the Arrows' base at RAF Scampton when the seat activated, throwing him into the air.
The parachute on the ejection seat did not deploy and he fell to the ground still strapped into the seat. He suffered multiple injuries and was airlifted to hospital, where he later died.
Rex Tedd QC, prosecuting, said there were still issues which need to be resolved and further discussions are to take place between prosecution and defence counsel to agree the basis of the guilty plea.
At the conclusion of Monday's 20-minute hearing, Mrs Justice Carr adjourned the case for sentencing, which will commence on February 12 and take up to three days.
She said "In light of the plea the matter will now proceed to sentencing. No health and safety case is the same. This case is unique like any serious case of its type."
Flt Lt Cunningham, who was from Coventry, had just completed his first season with the Arrows and held the position of Red 5 in the formation team at the time of his death.
An inquest in January 2014 was told that the ejection seat firing handle had been accidentally moved into an unsafe position and a crucial safety pin was incorrectly inserted.
In the four days before the pilot's death 19 seperate checks failed to spot the problem which the Central Lincolnshire coroner Stuart Fisher said was "there to be seen."
The inquest was told that when the ejection seat fired the parachute failed to deploy. The coroner ruled this was because a nut had been fastened too tight to a bolt.
Mr Fisher gave a narrative verdict at the end of a three-week inquest. He highlighted an issue that warnings about problems with the ejection seat had not been passed down to either pilots or ground crew who worked with the Red Arrows.
In a statement released after the guilty plea, Martin-Baker Aircraft Company said: "Firstly and most importantly we express our deepest condolences to the family and friends of Flight Lieutenant Sean Cunningham.
"Today Martin-Baker Aircraft Company entered a guilty plea to a single breach of Section 3 (1) of the Health and Safety at Work Act 1974. This plea was entered following detailed and lengthy discussions with the Health and Safety Executive which have considerably narrowed the issues from when its investigation first started.
"It should be noted that this was an isolated failure relating to the tightening of a nut during maintenance procedures conducted by RAF Aerobatic Team (RAFAT) mechanics.
"Martin-Baker Aircraft Company has designed and manufactured ejection seats for 73 years and in that time these ejection seats have been flown by 92 air forces, with over 17,000 seats currently in use. Our ejection seats have saved the lives of 1,050 British Royal Air Force and Navy aircrew, with a further 6,009 aircrew lives saved around the world.
"Martin-Baker’s priority has and will always be the safety of the aircrew who sit on the Company's seats. We appreciate that the Health and Safety Executive, during this process, has acknowledged this dedication and track record of saving lives."