Max Service ceiling for commercial airplanes

Ricky wrote in news:d853bc93-6705-4f74-bc06-
:


I remember learning recently in A&P school that 36,000 ft. is the
optimum altitude for long-range cruising. At approx 36,000 the temp.
stops falling & remains constant but pressure still decreases
resulting in a rate-of-thrust decrease that's more rapid at higher
altitudes than approx. 36,000.


Hmmm, it is true that the temp stops decreasing around there. (It's called
the Tropopause) but i never thought of it in terms of thrust like that
before. Rate of climb does get a little iffy up that high!


Bertie