EAA Sport Aviation

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5.) RUBBER HOSE
How it smells: Deep, sharp, acidic, toxic,
like burning tires or a car peeling out
Where it’s found: Fuel/oil line,
alternator belt
What to do: Shut off non-essentials,
watch ammeter, land, and investigate.

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6.) CARPET/INTERIOR How it smells: Acidic, plastic, unnatural, acrid, like burning tennis shoes Where it’s found: Along cockpit walls, floor, and panel What to do: Shut off heater, turn off non-essentials, watch the ammeter, try to identify source, land, and investigate.

I am one step closer to distinguishing a drop of smoking oil from a loose hose cooking on exhaust pipes.

Here is our unofficial, non-scientific analysis of what we burned and smelled.

1.) OIL How it smells: Metallic, hot, natural, dirty, like a hot airplane engine after a flight Where it’s found: Oil leaks can originate in a variety of places like oil lines, oil filters, etc., but it is likely to burn or smoke when coming in contact with hot surfaces like the exhaust pipes or cylinders. What to do: Monitor oil temperature and oil pressure; think about what’s been worked on recently (i.e., an oil change, filter, etc.). If the smell goes away quickly on its own, it may have just been a drop that burned up. If it continues or gets stronger, it may be a more serious leak. Either way, land and investigate.

2.) SCAT TUBING
How it smells: Mild, rubbery, like an
old gym mat
Where it’s found: Air intakes, heater,
carb heat system, etc.
What to do: Turn heater off.

3.) ELECTRICAL WIRES How it smells: Potent, sharp, unnatural, plastic, sweet, like toasted marshmallows Where they’re found: Wires to lights, instruments, panel, etc. What to do: Did you just turn something on? Turn it off. Did a circuit breaker pop? Turn off non-essentials. Monitor the ammeter. If the smell or smoke continues and you can’t identify the specific source, consider turning the master switch off.

4.) ELECTRICAL RESISTORS How it smells: Toxic, potent, unnatural, like burnt caramel Where it’s found: In avionics, instruments What to do: Look to see if an instrument or radio failed; pull the circuit breaker for that instrument if it hasn’t already popped. Does the smell continue or does it go away? Monitor the ammeter.

CONCLUSION

While burning smells are not commonly experienced in flight, they’re also not particularly rare. There is a hot engine just a few feet away from us on every flight, so we’ll all likely smell something eventually. It may just be a harmless drop of oil on a cylinder, or it could be the first sign something is not right and you need to get back on the ground immediately.

Every airplane has emergency procedures for such situations, and it’s important to know them for the aircraft we fly. However, practical understanding in diagnosing the situation can also be greatly beneficial.

Before those eight seconds at 9,000 feet, I thought my textbook answer about what to do with an electrical fire was sufficient. I still may not be able to tell a merlot from a shiraz, but I am one step closer to distinguishing a drop of smoking oil from a loose hose cooking on exhaust pipes.

I’m extremely thankful for my experience with Jeff. Flying with other pilots, especially experienced ones, can provide some of the best training for new pilots like me.