Perf Group A history
I have been trying to establish, out of idle curiosity, the history of the development of aircraft Performance Groups, particularly Perf “A”, with its rigorous treatment of engine-out operation. Web searches have produced little info.
I have seen a claim that Perf A originated with FAR25, which was first published in 1965, and that the first type certificated to FAR25 was the B737. Is that correct
This raises a few queries. What standard applied before that? To what standard were 1950s propliners, the Comet, B707, and DC-8 certified in respect of engine-out operation? I know that the FAA-approved B707 was rejected by the UK ARB, which required significant changes to the fin (vertical stabilizer if you’re from the US) and the rudder boost to improve engine-out go-around controllability.
Clearly, at that stage, there were major differences between national authorities. I suspect that alignment improved later – but the UK CAA still required changes to the Mmo of the B767 in the mid-80s.
When Perf A appeared, was it applied retrospectively to existing types? I recall that, maybe about late 60s, there were reductions imposed in the UK on the MGW of the DC-3, which were said at the time to make the type commercially unviable. Though, of course, it carried on flying for many years. I assume the change was to improve engine-out performance.
Further queries on performance criteria for some RAF types. I recall conversations with Shackleton pilots back in the 60s over a beer or three; they lived at times with a 20 knot gap on take-off between the stop speed and the go speed, thus giving in that speed band a horrid choice between a slow crash and a fast one. This was in the context of Gibraltar, with its short 6000ft runway, and Sharjah, rather longer but with temperatures frequently up to 40 deg C or so. Did that always apply? Or, at UK bases such as St Mawgan and Kinloss with longer runways, was there a higher level of safety?
Also, for the A-W Argosy, similar conversations in which I was told that at times they operated to “military performance standards”, whatever they were. The RAF Argosy first flew in 1961, so pre-dates (I think) Perf A. Did they operate to Perf A in normal times? What was the permitted degradation to “mil perf standards”, and in what circumstances could that be used?
I hope there may be some performance engineers out there with relevant knowledge.