Caught a fuel leak mid-flight on a Cessna 172 last Tuesday

I was doing a pre-flight inspection at KDVT in Phoenix and noticed a weird wet spot near the right wing root. Turned out the fuel drain valve O-ring was completely cracked, dripping about 3-4 drops a minute. Replaced it on the ramp with a $2 part from the parts bin before the flight even left. Anyone else had a small part like that almost ground you?

2 comments

2 Comments

evand657d ago

Oh man, that O-ring leak is a CLASSIC gotcha. I had the EXACT same thing happen at KAPA last summer, except I didn't catch it until I was already tracking fuel on the taxiway. Changed it out with a spare from the FBO's loaner kit, took maybe five minutes. Always amazed me how something that small and cheap can totally wreck your day if you're not paying attention.

lee_barnes707d ago

Hang on a minute, is it REALLY that serious? I get that a fuel leak is annoying and messy, but I've flown with a slow seep for a short hop in a pinch and it was totally fine. Those little O-rings cost like 50 cents and you can swap them in under a minute if you actually think ahead. I think people get WAY too dramatic about this stuff, like it's a catastrophic failure instead of just a minor nuisance. Nine times out of ten it's just a little dribble, not a fuel explosion waiting to happen. Honestly, I bet most pilots have let it slide at least once when they were short on time and came back to find it had sealed itself up from dirt or just stopped.