Here's a little addition to FAR Part 61, Pilot, Flight
Instructors and Ground Instructors, that you may not have noticed
when it appeared in the last few years...
The condition in which the apparent effect of gravity is zero, as
in the case of a body in free fall or in orbit. Also, cool new way
to spend a day for $2,950.
"Through semi-prepared runway operations testing and weighing
the aircraft after the take-offs and landings, we've seen anywhere
from 1,200 to 1,500 additional pounds of dirt collected in the
aircraft. We've seen enough dirt collect in the wheel wells to
where it was eight to 10 inches in depth."
Source: Lieutenant Colonel Bob Poremski, C-17
Integrated Test Force director, commenting on the results from the
first of a four-phase test program to chart the C-17 Globemaster
III's takeoff and landing performance on non-paved surfaces.