FAA Aviation Mechanic General (AMG)Ground Operations and ServicingMedium
A technician is preparing to service the main landing gear tires on a transport-category aircraft. Why is dry nitrogen specified for tire inflation instead of shop compressed air?
- ANitrogen prevents internal oxidation of the tire and rim, reducing fire risk from combustion
- BNitrogen makes the tire pressure gauge read more accurately
- CNitrogen increases the tire's load-carrying capacity beyond its rating
- DNitrogen is less expensive to produce than compressed air
Show answer & explanationAnswer & explanation
Correct answer: A. Nitrogen prevents internal oxidation of the tire and rim, reducing fire risk from combustion
Dry nitrogen is inert and moisture-free, which prevents internal tire oxidation and reduces the chance of an internal fire caused by heat from braking combined with oxygen and rubber vapor inside the tire, unlike compressed air which contains oxygen and moisture.
Why the other options are wrong
- B. Gauge accuracy is unaffected by the type of gas used.
- C. Load rating is determined by tire construction, not the inflation gas.
- D. Cost is not the reason nitrogen is specified; safety and performance are.
Nitrogen Tire Servicing
Aircraft tires are inflated with dry nitrogen rather than compressed air to reduce fire/explosion risk and internal oxidation.
- Nitrogen is inert and moisture-free
- Prevents oxidation-related tire degradation
- Pressure checked when tire is cold for accuracy
Memory trick: Nitrogen = 'No oxidation, No moisture' for safer tires.