PPRuNe Forums - View Single Post - Plane flips over after crash-landing in Somalia
Old 5th Aug 2022, 02:54
  #69 (permalink)  
hans brinker
 
Join Date: Nov 2010
Age: 56
Posts: 945
Received 0 Likes on 0 Posts
Originally Posted by fdr
Honestly, I have absolutely no idea other than a transfer function of kinetic energy, which goes against the teachings we get. I would not have believed that it does so, until seeing it first in airmasses over Japan in B747-200s, and even then, the observation is meaningless unless it works in reverse sense, and that also was observed. After that, I didn't need to pay for beer on Japanese trips very often.

The oddity was so curious I got the QAR data pulled to give some confidence that it wasn't observer bias. But if the temp and wind vector remains the same, yet your CAS sags out and the thrust comes on, then I can only assume that our teachings are an approximation of the real world.

If there was no inertia-related lag in the system, then there would be no such thing as a wind shear, wouldn't matter that the wind component dropped off 50 kts or not... or rose etc, as the aircraft would then be completely isolated from the outside world, and only referenced to the airmass, and it doesn't matter what the airmass does then. The reality is, it does indeed matter, and then I can only surmise that of the wind vector change causes a shear to be noted, then a vector change of the aircraft in the airmass would also cause a shear. There is only one case where the aircraft vector change really makes a difference and that is an extreme case, but still interesting, as if the plane is short of excess thrust, and enters a condition that is going to call for more than is available to maintain acceptable speeds. This is not an item that has only come up on beer bets, we had a number of aircraft that had speed excursions which resulted in an analysis as to why they ran out of puff.
Everything you have said is based on changes in wind speed and that is not the question.
hans brinker is offline