Originally Posted by
NSEU
There is also a flap extension trigger in the thrust logic (on 747-400/767-300), but I'm just exploring the "what if" extremes.
If you can't extend the flaps and weather has suddenly turned marginal (or worse) at all alternates, etc, then why not use all the tools at your disposal?
If the weather is down and the loc is broke, the approach in question is not a tool at your disposal. You must use another approach.
And if you are in VMC and the "loc is broke", then what is the harm? Isn't it something nice to have? Of course, you still have raw data to guide you.
Sorry, I don't know the rules of the air... purely an former engineer's questions/ramblings... Thanks for your response.
If you're in VMC and the autopilot must be on, there's always the vertical speed wheel. The ILS capturing logic, in my opinion, should be designed to meet the requirements of IMC, a much more critical flight regime. And those requirements are to capture the localizer before the glideslope. If you get a bad vector that puts you into the glideslope first, (an ATC error that is not extremely rare) and the crew doesn't catch it, you really don't want the airplane automatically descending below the cleared altitude. This is a must-have, and compromising it for a "nice to have" is not the way to go.