Nextleft,
It may not be as important today but missed approaches used to be designed so that an aircraft with a radio failure is put into a position where another approach can be flown. So straight ahead (until when???) is not a very prudent procedure. Amsterdam (and Heathrow in days gone by it would seem) rely on very quick action from ATC - much as I think that ATC people are good and will do their best, do you really want to rely on ATC who may have something else occupying their minds sort you out?? (By the way - just because the controller isn't talking, it doesn't mean that they're not busy.
Radio fail, straight ahead until when?
Until it said so on the approach chart and MATS Pt 2. Which at Heathrow was SAH to 3,000ft. Then at LON DME 10 turn left/right for EPM NDB and enter the hold. Then commence a procedural approach under normal r/t fail procedures. Pretty straightforward really.
Personaly I wouldn't rely on the new(er) missed approach procedures being totally failsafe without any ATC intervention either.
WF.