Assuming the AB letter is based on the TL of the reverser locked out engine not being moved to idle:
- Would the noise of the gear running through the water on the runway prevent the crew from hearing the "Retard" announcement?
- Would the TL position inhibit the spoilers, autobrakes and perhaps even the "Retard" announcement?
In the Dover C-5 accident, the problem engine was shutdown and a good engine was left at idle.
The discussion of that accident produced the opinion that it was better to move all the TLs together as it would not prejudice the shutdown engine and would avoid the risk of not using all the remaining engines.
The same doctrine may apply here as it seems more important to ensure the TLs are both at idle than to avoid attempting reverse on a locked out engine.