In general, check the formulæ and regroup them (currently split between HUD, autothrottle, different versions...)
[x] AJS approach alpha is just 12° or 15.5° (depending on α15.5° button). This applies both to the SI [1] and the A/T [2].
[x] JA approach alpha is computed to give an acceleration of 1m/s^2 at MIL power, minimum 9° [3].
This should be displayed on the TI [3]. (was already there, my bad)
[x] This approach alpha, capped to 12° (or 15.5° with the button) is used for SI speed error indication [3].
[x] This approach alpha, capped to 12°, is used as A/T reference in A/T mode 2 [4].
[x] In A/T mode 3 (α15.5° button on), the manual says the A/T reference is just 15.5°, without taking the computed approach alpha into account [4]. Is that an error in the manual?
[x] There is a graph of aircraft mass giving 1m/s^2 acceleration at MIL, at 12° and 15.5° respectively for the AJS. Even if it is for the AJS, it could help with computing this approach alpha on the JA.
edit: I decided to keep the exact same values for HUD and A/T. Doing otherwise seems surprising and would be confusing.
[x] JA rotation speed is "based on aircraft weight and acceleration, [...] minimum of 250km/h" [6], emphasis mine. Currently only aircraft weight is used. For the AJS, there is a graph of rotation speed depending on weight and A/B zone [7].
references:
[1] AJS SFI part 1 chap 17 sec 4.3.8
[2] AJS SFI part 1 chap 10 sec 2
[3] JA SFI part 1 chap 17 sec 4.4.3.1
[4] JA SFI part 1 chap 11 sec 5.1
[5] AJS SFI part 4 fig 13
[6] JA SFI part 1 chap 15 sec 4.13
[7] AJS SFI part 4 fig 8
In general, check the formulæ and regroup them (currently split between HUD, autothrottle, different versions...)
references: [1] AJS SFI part 1 chap 17 sec 4.3.8 [2] AJS SFI part 1 chap 10 sec 2 [3] JA SFI part 1 chap 17 sec 4.4.3.1 [4] JA SFI part 1 chap 11 sec 5.1 [5] AJS SFI part 4 fig 13 [6] JA SFI part 1 chap 15 sec 4.13 [7] AJS SFI part 4 fig 8