FAA Aviation Mechanic General (AMG)Ground Operations and ServicingHard
A technician is servicing an aircraft oxygen system and needs to select a compatible sealant or lubricant for a fitting. Which type of substance must be strictly avoided in oxygen system components?
- AAnti-static wrist straps used during fitting installation
- BDistilled water used to clean oxygen line fittings
- CAny hydrocarbon-based oil, grease, or petroleum-based lubricant
- DSilicone-based, oxygen-approved lubricants specified by the manufacturer
Show answer & explanationAnswer & explanation
Correct answer: C. Any hydrocarbon-based oil, grease, or petroleum-based lubricant
Hydrocarbon-based oils, greases, and petroleum lubricants must never be used on oxygen system components because they can spontaneously ignite or explode in the presence of high-pressure oxygen. Only oxygen-approved (typically silicone-based, non-hydrocarbon) lubricants specified by the manufacturer are permitted for oxygen system servicing.
Why the other options are wrong
- A. Anti-static straps address ESD hazards and are unrelated to oxygen system chemical hazards.
- B. Distilled water is not a fire hazard and may be used in some approved cleaning procedures.
- D. Oxygen-approved silicone lubricants are specifically designed to be safe for oxygen system use.
Oxygen System Servicing Hazards
Hydrocarbon-based oils and greases must never contact oxygen system components due to violent, spontaneous combustion risk under high-pressure oxygen.
- Only oxygen-approved, non-hydrocarbon lubricants (often silicone-based) are permitted
- Oil/grease contamination can cause explosion or fire in oxygen lines/fittings
- Technicians must keep hands, tools, and fittings free of oil/grease during servicing
Memory trick: Oil plus oxygen equals ignition — keep it clean and approved.