Safety Precautions - Aircraft and Workshop
Safety in the workshop and on the aircraft
Hangar accidents come from four energy sources: mechanical (engines, hydraulics, compressed gas), chemical (fuel, solvents, hydraulic fluid, paint, welding fumes), electrical and electrostatic, and stored mass (jacking, towing, lifting). A candidate must know the controls for each: PPE matched to the task (eye, hearing, hand, respiratory, fall protection), bonding and grounding during refuelling and defuelling, no smoking or open flame inside the refuelling zone, and a written hot-work permit for any welding, brazing, grinding or cutting near the aircraft.
Know fire classes and the extinguisher chosen for each: A solids (water, foam), B flammable liquids such as fuel, oil and hydraulic fluid (foam, CO2 or dry powder - never water), C gases, D combustible metals, and electrical fires (CO2 or dry powder after isolating the supply). Know that hydraulic fluid injected under the skin is a medical emergency, that oxygen and nitrogen cylinders must be secured upright, and that an oxygen-enriched atmosphere makes clothing and grease burn fiercely.
Traps in questions: choosing water for a fuel fire; forgetting that static bonding and grounding protect against ignition; assuming a permit for one task authorises another task or location; treating FOD control (tool control, shadow boards, caps and plugs) as housekeeping rather than as a safety system.
Rule of thumb: if a task needs a flame, a spark, a pressurised system or a person off the floor, it needs a permit, a second pair of eyes, and the aircraft made safe first - isolate, depressurise, lock out and tag.