Setting the MDA in the altitude window has been implicated in a couple of incidents. While is seems sensible to the dive-and-drive camp, a pilot would not desire the aircraft to level during a constant-angle approach. It would only serve to unstabilise the descent. The AP would have to be taken out and descent re-initated to the runway which could lead to a long landing.
The CANPA method requires the missed approach altitude to be set before starting the final descent to "unlock" the altitude hold. If that altitude happens to be the same as platform, our procedures require setting 100' above platform until the descent has begun, then reset to the missed approach alt. shortly thereafter. It requires deliberate action and thinking by a crew to get it right. It's an NPA, after all.
Last edited by FIRESYSOK; 17th Aug 2013 at 16:02.