A warning about a problem with a crucial part in the ejection seat in the jets used by the Red Arrows was not given to the Ministry of Defence, an inquest has heard.
The evidence was heard as the inquest into the death of Red Arrows’ pilot Sean Cunningham entered its second week.
Martin Baker Ltd, the manufacturers of the seat, sent the warning in a maintenance instruction document to a number of air forces including Pakistan, India, Italy and Finland over 20 years ago but it did not go to the MoD, the inquest was told.
The 1990 warning specified that the drogue shackle nut should not be over-tightened.
This week the inquest was told how the over-tightening of the nut could prevent the main parachute from opening in the event of the ejection seat being activated.
Flt Lt Cunningham,35, who lived at Burton Waters, near Lincoln, died in November 2011 after his seat fired him 300 feet into the air while he was on the ground preparing for take-off from the Red Arrows base at RAF Scampton.
His main parachute failed to deploy and he suffered multiple injuries when he fell back to the ground still strapped into his ejection seat.
Michael Cameron, after sales executive for Martin Baker, admitted in his evidence that the issue of over-tightening of the nut was a potential risk to life.
He said the company should have made it clear to its customers what the problem was .
Mr Cameron, who served in the RAF for over 20 years before joining Martin Baker, said: “I don’t know what happened at the time.”
Neil Mackie, who worked in the quality assurance department at Martin Baker for over 20 years before retiring, said he would have expected the warning about over-tightening the drogue shackle nut would have been communicated to ‘significant’ customers such as the Ministry of Defence.
He said it was also important that the shackle did not ‘pinch’ and was free to move otherwise this could also affect the deployment of the parachute.
Mr Mackie told the hearing: “I was more concerned with pinching the shackle. I made it crystal clear that under no circumstances must it pinch.”
Central Lincolnshire coroner Stuart Fisher is examining the circumstances surrounding the death of Flt Lt Cunningham including why the ejection seat activated and why the pilot’s main parachute failed to open.
The hearing at Lincoln Cathedral Centre is scheduled to continue into next week and is expected to conclude on 31st January.