ballyboley I know I should get the FCOM out, but for a quick answer...
On a single channel coupled approach, does the A/T still look at the Radalt? So it will still retard the throttles in the same manner and height as on a Dual channel autoland? And who's Radalt does it take the information from?
I cannot speak for the B738, but on the B732/3/4 when doing a single chanel approach, there is no autothrottle retard/flare mode, the aircraft will simply fly itself into the runway at the touchdown zone....RA has no effect on A/T when single chanel operations.
One point I am interested in is were these crews previously form a B732/3/4/5 type aircraft where a speed drop on the "old" annaloge ASI would have been a lot more noticable, and the information depicted on the B738 w.r.t. speed tape is not as quickly noticable and thus its depiction was not caught amongst the various other information given to the crew with the NG CRT's.