在 A320 和 A350 的襟缝翼卡阻不正常程序中，都比较清楚地说明了要选择速度来放构型（标黄部分），但对于进近速度是选择还是管理则没有那么清楚（标橙部分）：
A320 程序中只说了要减速到计算的进近速度，没说管理还是选择。A350 程序中，在一开始写了“USE SELECTED SPEED”，虽然理论上后面都应该按照这句话执行，但没有再说也可能会对机组造成误解。
如果在计算了不正常情况下的 Vapp，并在性能页面做了修改，选择速度和管理速度是一样的，而管理速度还有最小地速功能可用。如此看来，使用管理速度更有优势。
空客认为，A350 确实可以使用管理速度，但出于以下几点考虑，仍然建议使用选择速度：
- 与 A320 和 A330 程序保持一致
- 输入进近速度会增加机组进近期间的工作负荷
- 在某些情境下，PFD 上的特征速度会不显示，此时只能使用选择速度
- 由于在不正常襟缝翼构型下计算出的 Vapp 已经确保了足够的 VLS 裕度和擦机尾裕度，所以管理速度的最小地速功能意义不大。
第 1 条和第 4 条还是比较合理的，尤其是第 4 条，如果最小地速意义不大，那么管理速度最可能的优势就没有了。
关于第 2 条工作负荷，个人觉得没有什么道理，因为进近速度的输入是在进近准备期间就完成了的，而不是在五边再来输入，而就算五边再输入也不是什么大事儿。
关于第 3 条的"某些情况"，经过再次询问，空客解释是这种情况非常极端，几乎不可能出现，比如失去所有 ADR 和备用源数据。
TechRequest原文
Q1 :
In case of slat/flaps failure or jammed, we have to select speed for extending configuration. And when the landing config is established, should we manage or select VAPP?
In ABN PRO, "USE SELECTED SPEED" is capital emphasized. And in the video of AIRBUS-WIN, VAPP is also selected.
But after landing performance computing and VAPP revised, the selected and managed VAPP are the same. Why don't we manage it with the benefit of GS MINI?
A1 :
On A350, the FCTM PR/AEP/F_CTL.F/CTL.Abnormal Slats/Flaps Configuration states
QUOTE
\- The flight crew should use the selected speed
UNQUOTE
Airbus recommends to use the selected speed sets at the computed Vapp in the case of Abnormal Slats/Flaps Configuration for the following reasons:
- For commonality with A320 and A330 families, for which the use of selected speed is mandatory;
- It is technically possible to use managed speed, however, the flight crew would have to enter the selected speed as Vapp in FMS and switch to managed speed when established at the approach speed that leading to heavy workload to the crew during the approach.
- In some scenarios, the characteristic speeds may not be available. If they are not displayed on the PFD, the flight crew must use the selected speed.
- To fly the computed Vapp that will not be affected by the Ground speed mini function. The computation of the Vapp in the case of Abnormal Slats/Flaps Configuration ensures adequate speed margin against VLS and sufficient ground clearance to avoid a tail strike.
On A350, it is still possible to use managed speed for landing, but for the above reasons, Airbus recommends the use of selected speeds.
Q2 :
“In some scenarios, the characteristic speeds may not be available”. Will those scenarios can only happen in A320 and A330, or in A350 as well?
A2 :
In response to your request, we would like to confirm that whereas it is less likely to happen on A350 than on other aircraft, situations leading to the loss of the characteristics speeds may also occur on A350.
Indeed, scenario such as the loss of all ADRs and backup sources (FADECs and AOA probes) for example can lead to the loss of the speed informations.
However, from an operational standpoint, due to the number of design redundancies (and considering the number of failure to be accumulated), those scenarios remain extremely unlikely.
