The UK’s Air Accident Investigation Board has just published another interim report regarding the 08/2015 Hawker Hunter crash at Shoreham.(https://assets.digital.cabinet-office.gov.uk/media/5677d6bf…) with recommendations that the Civil Aviation Authority review procedures for the maintenance of ejector seats in swept-wing aircraft.
These are recommendations to correct safety or maintenance issues that have come to light during the accident investigation, they should not be interpreted as indicators that an ejector seat problem was the cause of, or contributed to, the crash.
Depending on how this all pans out, along with all the usual airworthiness worries, there is the potential that many vintage aircraft get grounded when they can no longer source new pyros. Hopefully, there won’t be a Daily Mail “Ground Everything” knee-jerk reaction.
Simply put, the explosive charges that go BANG in the ejector seats and canopy have an established shelf and working life. The Hunter needed new ones. The supplier said you’ll have to wait. Maintenance company signed off on flying with soon-to-be-expired cartridges, CAA said okay-if-you-say-so. New cartridges didn’t arrive on time. Signed-off again. (It appears this may be a regular occurrence in the realm of vintage aircraft as parts become difficult/slow to procure.) New ones arrived in June 2015 but were not fitted. I’ve no idea how long it takes to change them, so it’s possible the Hunter was out flying at displays and they were going to fit them once the season finished. There are other wrinkles due to a maintenance company change, an odd I’m-sure-everything-will-be-fine 6 year policy, and an excellent recommendation that first responders be told to look out for charges popping off if the canopy or seat are still in place... read the report.