Originally Posted by snowfalcon2
The missing pieces of data are a) the airplane's lift/drag curve in various configurations, which the manufacturer should already know, and b) the wind gradient in the remaining flightpath until touchdown (usually the headwind decreases, which in this case is good and adds margin if we simply use the instantaneous wind data).
So in theory it's not that difficult to devise a software that automatically commands the autopilot into optimum glide mode at the first sign of a thrust deficit that prevents it from holding the commanded glideslope at Vref.
I fully agree. There might be as well a data base of obstacles, allowing for the best way to avoid obstacles ...
However ... I have a more readily available solution :
1. Just tell us where the best glide speed is, in % of the VRef. That percentage is a constant for a given aircraft configuration. For an aircraft with a high wing aspect ratio, in a normal landing configuration, I suspect that the best glide speed is somewhere between 90% and 115% of VRef (educated guess).
2. The pilots already have a fair idea of the
wind gradient, because they know the instantaneous wind ... and the ground wind as well (being "wind minded" is a part of airmanship, isn't it?)
3. The stronger the head wind, the stronger the wind gradient (rule of thumb ...)
4. The stronger the head wind ... the higher the need to inscrease the speed somewhat above the best glide speed. Add one third to one half the head wind component. Additionnal benefit : the aircraft will be low sooner, where the head wind is less. Extra speed will convert back into distance. Extra distance covered in ground effect is a bonus, regarding drag reduction.
5. Let us know also for sure the real effects of partial flaps reduction.
6. The pilots can see the main obstructions, and deviate if necessary.
Nothing is sacrilege in such an emergency.
The first available software is in the pilot brain, its common name is "basic airmanship".
Perhaps there is a need to train from time to time for the maintenance of that precious software.