FAA Aviation Mechanic Airframe (AMA)Landing Gear SystemsEasy
A technician is servicing an oleo pneumatic shock strut and must add gas to the strut's air chamber. Which gas is specified by most manufacturers for this purpose, and why?
- ADry nitrogen, because it is inert and reduces the risk of internal corrosion or combustion
- BCompressed shop air, because it is readily available and free of cost
- CCarbon dioxide, because it condenses less at low temperatures
- DOxygen, because it provides the highest pressure per volume
Show answer & explanationAnswer & explanation
Correct answer: A. Dry nitrogen, because it is inert and reduces the risk of internal corrosion or combustion
Dry nitrogen is used to charge oleo struts because it is chemically inert, will not support combustion, and does not contain moisture that could cause internal corrosion, unlike compressed air.
Why the other options are wrong
- B. Shop air contains moisture and oxygen that can cause corrosion or combustion hazards.
- C. CO2 is not used for oleo strut servicing and is not specified by manufacturers.
- D. Oxygen is a serious fire/explosion hazard in contact with hydraulic fluid and should never be used.
Nitrogen Strut Charging
Dry nitrogen is used to pressurize oleo pneumatic shock struts because it is inert, moisture-free, and non-combustible.
- Prevents internal corrosion from moisture
- Non-flammable, unlike oxygen
- Standard gas specified in maintenance manuals for strut servicing
Memory trick: 'Nitrogen keeps it dry and inert - no fire, no rust'