一直以来，在如果襟缝翼卡在 0 位，为了复飞接通 SRS GA 模式，至少要将襟翼手柄放在 1 位。
空客在 2020 年发布的 FCGS X12 版本中，为 A350 引入了新的逻辑：2500ft RA 以及 AFS CP 高度以下，光洁构型也可以接通 SRS GA 模式。
需要注意的是，不正常程序 [ABN] F/CTL LDG WITH NO SLATS & NO FLAPS 中，仍然要求襟翼手柄放到 1 位，但对原因的解释有所改变。
老程序：
新程序：
关于 "approach logic"，空客解释说，这是 PRIM 的一个内部功能，主要是用来计算和显示一些速度分量。具体的并没有过多解释，空客认为机组无需了解。
TechRequest原文
Q:
Due to SRS GA engagement condition revision from FCGS X12, A350 can engage SRS GA in whatever CONF and lever position.
However, in [ABN] F/CTL LDG WITH NO SLATS & NO FLAPS, FLAP LEVER 1 is still required with explanation "in order to enable engagement of the approach logic in the PRIMs."
So what is that approach logic in the PRIMs which still need FLAP LEVER 1?
A:
Airbus reviewed your query, and we would like to provide you with the following information:
We confirm that for aircraft with FCGS X12, go-around procedures could be performed in a clean configuration for operational needs.
However, whatever the PRIM standard installed on the A350 aircraft, the action line “FLAPS LEVER 1…SELECT” is still necessary for the F/CTL LDG WITH NO SLATS & NO FLAPS ECAM procedure.
The reason is that the flap lever position is one of the criteria to activate the approach phase of the PRIM and therefore flap lever to 1 is required for “approach logic” in the PRIM. The PRIM uses the “approach logic” (this approach phase is an internal function inside the PRIM, not the APPROACH phase in the FMS) to adapt the computation and the display of several speed components.
In addition, the internal functioning of the PRIM and in particular the behavior of the PRIM in accordance with the different flight phases is not described in the operational documentation. The current layer 2 of the action line “FLAPS LEVER 1…SELECT” has been assessed as sufficient information for the flight crew.