Charges could still be brought in connection with the death of a Red Arrows pilot if it is found that safety laws were breached.
The Health and Safety Executive (HSE) said today that it was "continuing to investigate" following the death of Flight Lieutenant Sean Cunningham in 2011.
It comes after the Crown Prosecution Service ruled out any criminal charges being brought.
Flt Lt Cunningham, 35, was fatally injured after being ejected from his Hawk T1 aircraft while on the ground at RAF Scampton, Lincolnshire, on November 8 2011.
The parachute on the aircraft's ejector seat did not deploy and the South African-born airman died later in hospital.
Lincolnshire Police handed over a file concerning the Iraq veteran's death, but on April 30 the CPS said that, having considered all the evidence, no charges would be brought.
At the time, Alison Storey, specialist prosecutor for the CPS Special Crime and Counter Terrorism Division, said there was insufficient evidence to establish that any individual or the Ministry of Defence breached their duty of care to Flt Lt Cunningham in relation to the servicing of the relevant equipment.
She also said there was insufficient evidence to provide a realistic prospect of conviction of Martin Baker Ltd in relation to the manufacture of the parachute.