Posted by Bruce Kahl on December 10, 1999 In Reply to: Re: "Push
the envelope" posted by Arthur Smith on December 10, 1999 : : I
will accept the premise that "push the envelope" : : originated
with airline pilots, but I would like to : : know in exactly
what context: the actual practical : : mechanics of flying as in
the use of the controls : : relative to a certain aspect of
aircraft performance, : : the theory of flight as in
aerodynamics or the : : efficiency with which the aircraft
performs relative : : to outside forces, or some other practical
: : explanation? This expression comes out of the US Air Force
test pilot program of the late 1940's. The envelope refers to a
plane's performance capabilities. The limits of the planes
ability to fly at speeds and altitudes and under certain
stresses define what is known as its performance envelope. It's
an "envelope" in the sense that it contains the ranges of the
plane's abilities. "Pushing the envelope" is a good example of
how jargon -- the specialized or tec