can we now have an RTS without the completion of the safety case?
JSP553 - “The aircraft safety case must underpin the totality of the Aircraft Release to Service”.
Before entering service it was issued with a RTS certificate by CA. That, basically said, that the aircraft was safe to fly and operate within certain parameters. In effect it was its "safety case", and remained that way until around 2002.
You are speaking pre-GARP, so;
The Controller Aircraft Release was a statement by MoD(PE)’s Controller Aircraft (a 3 Star post) to ACAS (his customer) that the aircraft was airworthy at a given build standard; usually that presented at the Boscombe trials you speak of. Part of the underpinning evidence was the Safety Case or Safety Argument. The term “Safety Case” may be relatively new, but the basic work was still required to be carried out, regardless of what it was called.
Before signing the CAR, CA was obliged under the regulations to seek a firm statement from ACAS that the proposed CAR was acceptable, and that he (ACAS) would incorporate it within his RTS as Part 1. (Part 2 was Service Deviations or, if you like, variations from the presented Build Standard and representative of the In Use Build Standard). If ACAS was unhappy, the CAR was not to be signed, thus avoiding a situation whereby PE delivered an aircraft that could not be put to its intended use, safely. (Despite this regulation, CDP and successive Mins(AF) are on record as saying it is ok to dump an unsafe aircraft on the user and walk away. In my opinion, those who do so are guilty of fraud, maladministration and worse, but I can’t say too much because they are now very senior in DE&S, so I’ll just sit on the fence and say 15 years hard labour would do the trick).
ACAS issued the RTS, which was his statement to the Users that the aircraft was airworthy and, upon Initial Issue, he signed a letter of promulgation which was the authority to fly the aircraft in service.
Our (UK) system is limitations based, so “CA Release trials” were conducted to determine, for example, the installed performance of avionic equipment, from which any limitations were derived. It follows that one needs a performance baseline; for example, when the Nimrod Mk1 was modified to Mk2, the Build Standard, Safety Argument and CAR/RTS of the Mk1 had to be maintained and current otherwise the Mk2 had no baseline from which to work. Similarly, MR2 to MRA4. (I imagine this is where MoD and BAeS are having a lot of trouble, because it is highly unlikely the MR2 pre-requisites are in order). This applies to any such conversion or modification programme – MoD’s most notable failure in this respect was Chinook HC Mk1 > Mk2, where the CAR and RTS were issued before the installed performance of most of the avionics was established, meaning very little of it was actually cleared for use. In fact, far from the Mk2 having a valid Safety Case/Argument, CA and ACAS signed their Releases in the knowledge Boscombe had declared Safety Critical Software “positively dangerous”.
I mention Chinook because, of course, it shared a MoD(PE) 2 Star with Nimrod. If one aircraft was screwed up, it more or less followed that they all were as staff worked under the same directives. Which was precisely the point made by MoD staff prior to the Nimrod accident (when failure to implement airworthiness regs was notified directly to Adam Ingram), and reiterated by ACM Loader in the BoI. And why Haddon-Cave’s conclusions came as no surprise whatsoever.
Faced with that degree of Gross Negligence by MoD, you ask very good questions DV.