FAR part 25.733(e):
"(e) For an airplane with a maximum certificated takeoff weight of more than 75,000 pounds, tires mounted on braked wheels must be inflated with dry nitrogen or other gases shown to be inert so that the gas mixture in the tire does not contain oxygen in excess of 5 percent by volume, unless it can be shown that the tire liner material will not produce a volatile gas when heated or that means are provided to prevent tire temperatures from reaching unsafe levels."
From
Michelin Aircraft Tire Service Manual:
"NOTE: Michelin recommends that all tires, regardless of position or aircraft rating, be inflated with dry nitrogen of at least 97% purity. Some OEM (airframers) recommend 99.5% purity. When adding 97% pure nitrogen to an “empty” tire, the nitrogen concentration will end up about 95% when the pressure reaches about 125 psi. When the operating pressure is less than 125 psi and the desired concentration is ≥ 95% nitrogen by volume, use a double inflation process if the source nitrogen is 97% purity."
Consider
the Space Shuttle tires:
"Like most aircraft tires, the Space Shuttle tires are filled with nitrogen because of its stability at different altitudes and temperatures. Due to the extremely heavy loads, these bias ply tires are inflated to 340 psi (main gear) and 300 psi (nose gear). The main landing gear shuttle tires are only used one time, and the nose landing gear tires are used for two landings."
Here what they looked like after one landing:
Last edited by riff_raff; 18th Jan 2016 at 01:15.
Reason: More information