感谢同事的问题。
DSC-22-FG-50-50 C A/THR SOFT MODE 中提到 A/THR SOFT 模式的激活条件包括：
The speed/Mach control has not changed from managed to selected mode during the last 10 min
那么，以下两种情况都符合这个条件么：
- 10 分钟之内一直是管理模式，没有转换为选择模式
- 已经转换成为了选择模式，但这个转换是在 10 分钟之前完成的
空客回复是，在其他条件都满足的情况下， “10 分钟内一直是管理模式”这一情况是符合的。
而如果 10 分钟之前转换到了选择模式，但在 10 分钟内没有改变选择的速度目标值，A/THR SOFT 模式也会重新激活。这一点 FCOM 中到时没有说清楚。
另外，关于 A/THR SOFT 模式，其实 21 年之前并没有 10 分钟这一个条件，是在升级了 FCGS Standard X13 之后是修改过的，以改善飞机对风梯度的反应。
TR-81779046 原文
Q
DSC-22-FG-50-50 C A/THR SOFT MODE 中提到：
The speed/Mach control has not changed from managed to selected mode during the last 10 min
请问以下两种情况都符合这个条件么：
- 10 分钟之内一直是管理模式，没有转换为选择模式
- 已经转换成为了选择模式，但这个转换是在 10 分钟之前完成的
也就是 A/THR SOFT MODE 的必要条件是“必须是选择速度”，还是“10 分钟内没有转换”？
As stated in DSC-22-FG-50-50 C A/THR SOFT MODE:
The speed/Mach control has not changed from managed to selected mode during the last 10 min
Do both of the following situations meet this condition?
- The mode has been in managed mode and has not switched to selected mode within the last 10 minutes.
- The mode has already switched to selected mode, but the switch was completed more than 10 minutes ago.
In other words, is the necessary condition for A/THR SOFT MODE that the speed must be in selected mode, or that there has been no switch within 10 minutes?
A
We confirm that both situations meet the mentioned condition.
In order to clarify, we would like to inform CSC that, as indicated in A350 FCOM DSC-22-FG-50-50-SPEED/MACH Mode-A/THR SOFT MODE, a design change was introduced to improve the aircraft reaction to wind gradients with the FCGS Standard X13 installed in the entire CSC A350 fleet.
With this new design, the A/THR soft mode is inhibited for 10 minutes when the Speed/Mach control is changed from “Managed” to “Selected” mode. This enables the A/THR to react quicker to the speed variations.
As a result, if the managed mode has been active for at least 10 minutes without switching to selected mode, the A/THR mode activates (i.e. provided that all the other activation conditions are met).
If the flight crew selects the selected mode and keeps it for 10 minutes without changing the selected target speed, then we confirm that the A/THR soft mode reactivates.
Then, if the flight crew changes the selected speed target, the A/THR soft mode deactivates.
