ever lose a fuel cap in flight?

[cjensen]

I lost a cap on a Comanche once...lost 14 GALLONS in one trip around the pattern!!

I'm willing to bet the cap is near where you rotated. Once the wing generates lift, the pressure on top of the wing would suck the cap right out if not locked down. Check that area, and I bet you'll find it...

[JoeBlank]

Operational checks and maintenance of fuel caps is on my Condition Inspection checklist so they get looked at every year. Proper tab tension, wear plate condition, tab shoulder wear condition, O-ring condition, and overall cap fit tension are critical. Both the stem seal and the large Viton O-ring should be lubricated with a film of Fuel Lube or EZ-Turn Lubricant.

A visual check of the caps is part of my pre-launch checklist. (CIGAR- "C" is for Controls & Caps). I can easily see them from the seat of any of the RV models (except -12).

Don't leave home without 'em...

[sandifer]

As mentioned, check the snugness of the cap on pre-flight. When fueling, put the cap in your pocket, so there's no chance of putting it down and forgetting to put it back...you'll notice it in your pocket when you attempt to strap in. Have a spare on hand. I never lost one in the RV, but did in the Pitts once (negative G) due to degrading rubber and lack of pre-flight check. The cloud of fuel spray over the canopy got my attention.

[elippse]

Last year shortly after takeoff some motion caught my attention out at he left wing; sure enough, the cap had come off. The hole in the wing is behind the maximum thickness and the fuel level was only half-way so there was no fuel emerging.

The cap had been showing signs of coming loose previously and I thought I had fixed it with silicon grease to allow the plunger to pull up on the rubber donut without friction. My friend had had a similar loss of one cap on his plane. So I made two fiberglass-foam caps that fit the wing curvature with minimal gaps. They are fitted with screws that go through the center and farther along through a bar with a threaded hole in its center. This bar is wider than the opening so it has to be slipped through at an angle. The end of the screw below the bar is fitted with a metal lock-nut so that the travel through the bar is limited; it can't be unscrewed! I just loosen the screw and jiggle the cap around until it comes out of the hole. To close I angle the bar until it goes below the opening, and then tighten the screw to pull the cap securely into place. No more lost caps!

[dpansier]

Many certificated airplanes use a cable or bead chain to contain the fuel caps, the disadvantage on the RV would be the retained caps may damage the visible wing surface when blown around.
Any thoughts?

[flyvans.com]

some aircraft have their fuel caps attached to the tank via a small chain or similar.
my understanding however is that this is not to keep the cap from getting lost but rather for static grounding. in theory, a fuel cap in your hands that isn't grounded to the aircraft could cause a spark. however, with all the standard rv fuel caps (ungrounded) and the assumingly many refueling cycles, i think it's safe to say that this theory has very little merit. at least haven't heard about a flock of refueling accidents involving rv's...

that aside, losing a cap is probably one of the "classics", along with an unlocked canopy etc...
hasn't happened to me yet but may someday. just fly the airplane first.

we have the retrofit key-lock insert caps from the van's catalog installed and like them. first of all, they look nicer and secondly, chances are that you are holding the cap by holding the key and are more likely to reinstall them right after removing the fuel nozzle.

regards,
bernie

[Tom Martin]

I lost a cap years ago on my RV4. The tanks were filled by the airport and I did not check to make sure that they were secure. I was twenty five miles away when I noticed it. This was about half way through my first 25 hours, on my first project! Fuel was streaming out of that tank but the other one was full so I was not worried about the amount of fuel that I had, but I did have 10 or 15 minutes to worry about sparks etc on the way back to the airport. When I went to land the runway was covered in seagulls and I admit that I was so distracted by the loss of the fuel cap and the consequences of having to go around that I let my speed get too slow. I caught it in time but it sure brought home what can happen when you focus on just one aspect of flight.
The birds walked off the runway as I was getting ready to go around and later we found the cap half way down the runway, on the centre line, undamaged.
There have been no lost caps in the last 16 years!

[petehowell]

If you use Fuel Lube in the northern climates, the caps will never come off in the winter! I think Mel suggested Lubriplate, and I have found that to be ideal here in Wintersota.......

[Kyle Boatright]

I lost one at about 100' and 100 knots on departure from a fuel stop. In my peripheral vision, I noticed a dark object (I assumed a bird) zip by my left wing. When I looked, no bird, but no fuel cap either. I made a mental note of my position over the field immediately after realizing what happened.

I flew an abbreviated pattern, noticing that the tank spewed fuel at high angles of attack and didn't at lower angles of attack.

Then I landed, parked, and walked the runway starting at the point where I saw the cap depart. I found it off in the weeds beside the runway, slightly dinged, but useable. I continue to use that cap as a reminder.

BTW, I had assumed the fuel guy had replaced the cap and he assumed the opposite. My fault entirely.

[Jekyll]

23 years in Marine aviation - saw a number of gas caps come off. The worst I ever saw was an F/A-18 Hornet loose a cap off a center line drop tank on take off in the late 80's. Big fire ball when the fuel mist hit the afterburner. The pilot ejected safely.

I'm not suggesting this can or will happen to an RV. Easy to put it on your check list to check caps after run up.