Tuc,
Thank you for, as ever, timely and accurate addition to my overlong post. The newer MAP-01 regs aren't quite as clear cut (I think) but the main thrust is clear - if the DA is involved, it's an SI or an STI.
What's much clearer is what is supposed to happen when putting together any TI. I quote from MAP-01, Chapter 10.5.1 Para 1.1:
Prior to issuing an SI(T) (which includes RTIs) the TAA in conjunction with the Release to Service Authority (RTSA) and Handling Squadron (HS) must assess its effects on the Air System Safety Case, RTS and handling and operation in accordance with RA 5405.
So, when the HSA issued the RTI, who certified that they had assessed its effects on the safety case for the seat? They must have done, to issue the RTI as per MAA regs. But there WAS NO safety case for the seat. This is a clear failure of the HSA's airworthiness management process. And where was the RTSA? Did they also not know that the seat didn't have a safety case? And where was the MAA? When they assessed the HSA and the seat PT, how come they didn't spot that there was NO safety case?
Come to that, how did the RTSA issue an RTS in the first place without a seat safety case? How did ACAS sign that one off?
Once you start digging, you don't stop until you find the truth.
Best regards to all those who care, and do their best.
Engines