Originally Posted by
busTRE
Peplum and others:
You simply cannot use ground speed.
The wind could easily be 150kts or more in any direction ( I don't kow where you get the idea that 75 is a maximum Peplum, it just isn't). So, if you maintain 400lts GS as you suggest you might be doing 250 or 550 or anything in between. i.e. you have no idea. At near to service ceiling the safe speed range can be as little as 30 kts wide and yet you think it is fine to use a method that has a 300 kt (or more range of error). I can only assume you are not professional pilots to have made such a basic error.
Where do you take the 30kts from?
WRT to ground speed the margin is roughly 100kts GS. (~M0,68 - ~M0,86)
The mistake you made is the same one sees over and over again. the 30kts range is IAS. For inertia of the airframe, it's GS that counts. IAS is aerodynamics, Gs is mechanics.
You can't have it both ways, sorry.
GS 400 kts would have been btw much better in any case than GS 110kts (that's what they had roughly). GS should have given them a clue how the thing was plowing through the air. Even if not exact enough for perfect flight, it might have saved the day.