Where should fuel stains be located to not be considered a flight hazard?

Fuel stains should be located outside the aircraft and away from ignition sources to be considered not a flight hazard. This is because fuel vapors can ignite when they come into contact with sparks or open flames. Having stains located away from these potential ignition sources greatly reduces the chance of an explosive situation occurring.

Fuel near wing tanks is problematic since the wing is critical for flight, and any fuel leakage in that area could lead to significant hazards. Fuel stains underneath the aircraft could also pose a risk, as it may not be easy to ensure they are away from ignition sources, especially during maintenance activities where personnel and equipment are in close proximity. Lastly, fuel stains inside engine compartments are particularly dangerous, as engines operate at high temperatures and are more likely to ignite any fuel present.

Therefore, the safest scenario is for fuel stains to be located away from the aircraft and any potential hazards associated with ignition sources.