这个问题在 DSC-32 - Landing Gear#SUMMARY OF BRAKING MODES 中已经说得比较清楚了。空客在回复中也同意了这个 Braking Mode Summary 信息不全，以后会在下面增加脚注，表明在两部 BRAKES CTL 都不工作的情况下，A/BRK 是不工作的。
参考 DSC-32 - Landing Gear # SUMMARY OF BRAKING MODES ：
手册中提供了一个刹车模式的总结表：
但需要注意的是，这个表其实不全。比如 A/BRK 是否可用只和 BRAKES CTL 工作与否有关，而并不是和正常还是备份刹车有直接关系。所以下面两种状态也是可能出现的：
这是因为刹车模式和功能同时受到控制器（BRAKE CTL 和 RBCU 好几个通道）、液压供给、A-SKID 开关等多方的影响，相互叠加可能出现很多种状态，在一个表中无法简洁表示出来。
所以也最好是分开来看各种降级的逻辑，会更容易理解：
原文
Q1:
As described in DSC-32-20-10-20 C REMOTE BRAKING CONTROL UNITS (RBCU):
If in the condition of BRAKES CTL failure, the situation should be as follow:
However, in the SUMMARY of DSC-32-20-10-40 F SUMMARY OF BRAKING MODES, there's no such situations：
For the NORM and ALTN mode in the table above, as A/BRK available, we can know controller is BRAKES CTLS instead of RBCU.
So, does the situations which normal or alternate mode controlled by RBCU exist? And if it is, which ECAM alerts should be corresponded with?
A1：
In response to your query, we would like to confirm that by design, in the event of loss of both Break Control Systems sides, the RBCUs (channels 1B and 2B) will take over control.
In such a case, the Normal and Alternate braking modes will remain available but the autobrake function will be lost (pedal braking remain possible).
Regarding to the cockpit effects, those will depend on the different failure leading to the loss of the two BCS sides but the ECAM BRAKES AUTO BRK FAULT and Dispatch Message BRAKES CTL 1+2 (at least) will be displayed.
Q2:
Should these two modes be added in "Braking Modes Summary"?
A2:
After internal review, the solution retained to address your remark is to add a footnote in the Braking Mode Summary table in order to indicate that in Normal and Alternate Braking mode, Autobrake is not available if both BRAKES CTL are inoperative.
