What precaution must be observed regarding tools used when servicing an aircraft oxygen system?

• A. Be sure that there is no oil or grease on the tools.
• B. Use oil on the tools.
• C. Use only plastic tools.
• D. Store tools in water.

Answer: (A)

Oxygen systems create an environment that easily supports combustion, so any tool that might contact the system must be completely oil- and grease-free. Oil or grease on tools can act as fuel in an oxygen-rich setting, and even a tiny residue or a spark from tool contact can ignite it, leading to a rapid fire or explosion. That’s why the standard practice is to keep tools dry and clean, free of petroleum-based lubricants, and to wipe them with a clean dry cloth or use oxygen-approved cleaners if needed. The emphasis is on removing all hydrocarbons from tools that will touch oxygen-system components.

Using oil on tools is hazardous because it introduces fuel into the working area. Relying on plastic tools doesn’t inherently solve the risk, since residues or compatible-but-flammable plastics could still pose problems. Storing tools in water is unsafe for multiple reasons, including corrosion and mishaps during handling. The key idea is ensuring all tools are oil-free when servicing oxygen systems.