Originally Posted by
misd-agin
B757-200W and 737-800W - approx. 19.5:1 calculated sink rate/TAS in the airplane.
This is a fact that is easily overlooked when discussing Glide Ratio.
Aerodynamically the correct glide Ratio is sink rate/IAS. When calculating how far you can glide with regard to Mother Earth, it becomes sink rate/TAS.
When starting the glide at >40k this will make quite a difference, so with an aerodynamic glide Ratio of 12 an effective glide Ratio regarding the Earth of ~16 - 17 could be expected.