RetiredBA/BY,
I'd like to add a couple of points to Tuc's (customary) excellent reply.
As the SI report makes clear, the RTI (RTI/59) was developed in response to discovering a crack in an ejection seat top cross beam in July 2010. With assistance from MB and 1710 Naval Air Squadron (the latest incarnation of what was once the Naval Aircraft Materials Laboratory , the MoD's only dedicated material testing and NDT laboratory) it was determined that a visual inspection for cracking every 14 days was appropriate, and that the seat could safely be operated with a cracked beam. This was recommended to the Hawk Support Authority.
Things now get hazy due to the lack of meeting minutes , and indeed of almost any records of the decision trail. In early August, the Hawk SA, with the AES PT, produced RTI/59, which called up a full NDT inspection of the beam, requiring disassembly of the drogue shackle. From the SI report, it appears that a meeting took place later in August chaired by 22 Group, acting as the Aircraft Operating Authority (AOA). The SI report says that the AOA was 'not content to operate the aircraft with a cracked cross beam as the visual effect might undermine aircrew confidence in the system'. Four further iterations of RTI/59 took place between August and October 2010 (unusual), leading to a 50 hourly check with associated disturbance of the shackle. The SI report notes that this 50 hourly NDT check was kept in place even after 1710 NAS had provided assurance to the PT that a visual (non-dismantling) examination was adequate.
In my view, the PTs (Hawk and AES) didn't have to impose the full RTI/59 on the seat. 1710 and MB had told them a visual inspection was OK. It appears that it was 22 Group who demanded the full NDT inspection so as not to 'undermine aircrew confidence'. Even after further assurance from 1710, the full RTI was kept in place. So why did 22 Group get to call the shots? Why did the PTs go for a full NDT inspection and shackle dismantling? Did the PTs get 'told' what to do by their aircrew? We just don't know. No minutes or records. The MAA saw all this as an 'other' factor. I respectfully disagree, and consider the failure to properly consider all the safety implications of this RTI to be a 'contributory' factor. But that's just my view as retired engineer. Doesn't really change the price of fish.
Best regards as ever to all those doing the work,
Engines