In article ,
"Mortimer Schnerd, RN" writes:
Ian MacLure wrote:
Operationally its irrlevant because the FAA limits speed below 10K
ft to 250Kts IIRC.
As to the actual max speed attainable at low altitude, I believe you
have it correct.


Agreed. Thicker air equals lower speed. FAA equals even lower speed.

Not necessarily - thicker air also = much more thrust. It's all pretty
much a wash, with a transonic airplane. Usually the TAS in units/time
(mph, kts, km/hr) is higher, but the Mach Number's a bit lower. *The
Speed of Sound is proportional to absolute temperature. It's warmer
near the surface, so there's more mph/Mach Number.

--
Pete Stickney
A strong conviction that something must be done is the parent of many
bad measures. -- Daniel Webster