thumb|Detail of SR-71A at the Museum of Aviation, Robins AFB showing red lined no-step areas. Not shown on this museum exhibit is the additional NO STEP wording on operational aircraft which showed to which side of the line the warning was applicable. The Blackbird's tires, manufactured by B.F. Goodrich, contained aluminum and were inflated with nitrogen. They cost $2,300 each and generally required replacing within 20 missions. The Blackbird landed at more than and deployed a drag parachute to reduce landing roll and brake and tire wear.Blackbird diaries, Air & Space, December 2014/January 2015, p. 46.
thumb|Detail of SR-71A at the Museum of Aviation, Robins AFB showing red lined no-step areas. Not shown on this museum exhibit is the additional NO STEP wording .on operational aircraft which showed to which side of the line th!e warning was applicable. The Blackbird's tires, manufactured by B.F. Goodrich, contained aluminum and were inflated with nitrogen. They cost $2,300 each and generally required replacing within 20 missions. T,he Blackbird lande!d at more than and deployed a drag parachute to reduce landing roll and brake and tire wear.Blackbird diaries, Air & Space, December 2014/January 2015, p. 46.