ever lose a fuel cap in flight?
 

Well, Yesterday was a bummer. I had planned an overnight trip to Waterloo from Ottawa (about a 1.5 hour trip) to have dinner with some friends. The weather was looking good, high ceilings and good forecast for the return trip. Long story short, I had a tonne of things to do to get ready, and it took me most of the day. Plus I had to wait for enough of the runway to be plowed so I could get out (we'd gotten hit with a dumping of snow the night before). Finally, at 2:30pm, I was ready for takeoff (which would have me in Waterloo well in time for dinner). Smiling, I throttled up and took off. Within seconds I felt a bit of something like the left wing dipping a touch, which I thought was just a bump of turbulence. I looked to my left and saw a missing fuel cap and fuel spraying out. ****. I checked that I was on the other tank (I was), and proceeded to climb into a circuit for an immediate return. I speculate that the slight wing dip I felt was as the fuel cap blew off the drag profile in the area around the missing fuel cap was suddenly different.
I have no idea what happened to the cap. I remember checking them both before takeoff. I'm guessing that maybe with the cold weather the seals had dried out or contracted? Weird thing is, i've been flying in colder weather than that several times over the last month.
My lesson-learned, I ordered a replacement cap plus a spare, which I will keep in my emergency tool kit in the back of the plane, so I have a spare one when I'm away from base.
I was really bummed out not to make it to Waterloo, but perhaps this was fate keeping me from making that flight for some other reason unbeknownst to me.

I know a guy in a 6A who lost one. I do not recall the specifics.

As for your case, if there is a failure mode that I am not familiar with this could assist me in my never ending education process.

However, I have for years kept a spare fuel cap and assorted parts in the plane.

On a related note, what is the exact size of the fuel drains? Is it a 1/8 inch NPT? The reason is I want a spare in case I have a failure of one of those.

I lost a cap on my Cherokee 180 when my daughter forgot to put the cap back on after refueling and I didn't double check her either.

Fortunately, I noticed it on take off, flew a tight pattern, and landed. The fun was looking for it on the runway. It took awhile, but we found it. Fuel loss wasn't too bad.

Lost a fuel cap in a Long EZ
 

Fortunately the openings were expertly located by Rutan to miss the prop if that ever happened. I had just before lubricated the seal to help keep it from drying out with a small shot of silicone spray. That was enough to lose the friction on the rubber seal . Have a similar cap on my RV9 that is maintained quite tight with no lubricants. !

I tossed a "spare" cap on one day to go fly formation. About 5 minutes in to the flight I look over and the cap is sitting about a half inch high and fuel is pouring out. I broke off the flight and headed back. The cap turned around a few times but never left the airplane. It was latched but maybe was adjusted for a different flange. It was interesting to say the least.

I lost one immediately after take off one day after I forgot to flip the lock down. I saw it fly off out of the corner of my eye and realized immediately my error (after just refueling). Landed, found some aluminum speed tape, put a couple of layers over the hole and I was on my way.

I did not put the lever down on one cap during my preflight when someone came along and started talking to me. I was in my hangar on my home field. I took off from my home field for one circuit. When I landed and shut down, I saw that the cap was missing. Looking on the runway, it was about 75 feet down the runway from where I started my takeoff roll. I had already installed my spare cap from my tool kit when I retrieved the old one. Since the old one was polished and engraved, I put it back on the airplane.

This happened on the 2nd weekend of this year after I have flown the airplane more than 13 years and 2,400 hours. Yes it can happen to me. Like an old FAA inspector once told me. "In God we trust. Everything else we check."

Not sure about the size, but the common failure mode on these is a damaged o-ring. I ordered a couple extra ones and carry those with me on x-country flights.

WRT losing fuel caps, add "check fuel caps" to your engine-run up check list and USE THE CHECK LIST and you should avoid this problem.

erich

I have never lost one in fight but always take a look at the caps when doing a control check.

Also, I carry an extra cap (and quick drain) in my tool bag.

The thought of losing a cap is exactly why I did NOT have my N-number engraved on them, only the fuel requirements.

PS. Fuel lube on the O-ring will help increase the life of the rubber part and aid in securing the cap.

Yes, 1/8" NPT. A plug will work just fine to get you home if you want to pick up something at the nearest home improvement store.