orifices so that damping during compression is less than during rebound. Oleo struts absorb and dissipate forces by converting a portion of the accumulated kinetic energy into thermal energy. Pneumatic systems like the oleo strut generally have long operating lives, and the construction is not unusually complex for maintenance purposes. Nitrogen is usually used as the gas instead of air, since it is less likely to cause corrosion. The various parts of the strut are sealed with O-rings or similar elastomeric seals, and a scraper ring is used to keep dust and grit adhering to the piston from entering the strut. See also FedEx Express Flight 80 – bounce during landing leading to crash References Aircraft undercarriage Telescopic shock absorbers