A simple check to ensure the shackle rotated about the bolt should probably have been wise. As this was essential to parachute deployment.
MB knew of the issue and had told other operators but apparently could find no evidence of having told their most “intelligent” customer.
Very recently (days, and too late), a report came to light showing MoD knew of various issues in 1999. This was concealed/withheld from Service Inquiry, Coroner, CPS, HSE and Police. The penny probably dropped that one MoD office had inadvertently released evidence that another sought to conceal, so the associated reports giving finer detail have not been released. (This has happened before, and is what sunk MoD on Mull of Kintyre). FoI requests are now rejected.
It is known that even if the shackle was free to move by hand, it could occasionally jam when under load. The design worked to the original aircrew weight spec, but not when it was changed to take account of heavier (male) and lighter (female) crew. This resulted in a modification to one seat variant, but not that fitted to Hawk. The question is why that mod was not adopted in Hawk. It is not as simple as a design flaw. It is more a case of an adequate design becoming less so when the spec is changed. This is routine, every day stuff to EAs and TAs in MoD; and industry.
This does not exonerate M-B over the claim not to have sent information to MoD in 1990 (demonstrably they informed BAeS, and it becomes a case of who was responsible then for initiating aircraft tech pubs amendments), but it does prove conclusively that
MoD was wrong to claim it did not know in 2011. Legal authorities were misled by omission. Perjury is a possibility.
Why did M-B not use this report as evidence that MoD knew? We know the answer. Their solicitor's stated strategy of 'not upsetting MoD'. In my opinion, this makes all concerned complicit in future accidents that share this root cause (systemic airworthiness failings). We've been here before, too often.