I would appreciate some opinions on whether to fly with a seemingly slight? fuel leak from my left wing sump drain. The plane is a Cessna 182P. The drain stem was removed to drain fuel when the fuel selector valve required repair a month ago. It seems the leak could be the seal. The tanks are nearly full and I had planned to fly out to the backcountry for a day. I would like to fly, use up the fuel and then tend to the leak. I have included a photo. There is not enough of a leak to collect on the ground. It seems to just stain the areas shown. There is no fuel smell inside the cockpit. Do you think it is safe or advisable to fly for a day, deplete the fuel and then effect repair? Thank you.

It could also be the fuel sender gasket or (God forbid) the bladder. The bladder was replaced in 2005.

Well, hard to say without pulling some fairings. I'd prob err on the side of caution if headed into rough terrain vs flying over farmland.

Odds are the o-ring in the sump drain was galled in the process of taking it apart or putting it back together. Google "Curtis valve o-ring"

Fuel leaks are a serious business and not to be trifled with. I was thinking about bidding on a 170B in WA that was totaled by the insurance due to a fuel fire. They didn't see any signs of fuel, but could smell it pretty badly. They decided to land and have it looked at by the shop on the field. After the bird had sat for a while on the ramp, the owner went over to the plane to tow it over to the shop, and when shutting the door (so his story went) created a static discharge that set the fuel afire. True or not, anyone who has lit an AvGas soaked towel on fire (dont ask) knows how scary that stuff is when it burns.

Get it fixed brother!

IIRC my wet wing Mooney manual said if you could see liquid fuel it was unairworthy, but if all you saw was stains it was airworthy. There were 4 or 5 levels of fuel escaping, and I can’t remember all the names, but they considered only the last two levels an airworthiness issue.

I would have to think long and hard about heading into the backcountry with evidence of a leak. My rule is if I have to ever think long and hard, don’t.

I have pulled my 172 drains and had a buddy stick his finger in the hole and not lost much fuel, pick someone who is a true friend though...

Rod

F F F

Fuck it Fly it Forget about it



If your lucky its just something loose. The tank probably dried out and rotted out when fuel was drained to repair the selector. I bet you need a new tank. Rotten vent line.

When the sump oring goes, it usually leaves a stain on the hangar floor. When the bladder has a leak, it usauly stains the skin and creeps its way down the door. I would be willing to bet its a leak in the bladder. Ive changed three 182P bladders in recent times. It usualy deteriorated around one of the nipples. Have fun!

I hate to say it, but it looks like a bladder to me. Anytime I've had a sump leak, the staining is only aroun and aft of the sump. Never had it ahead of and outboard of the sump. The staining along th rear rivet seam heading outboard is what makes me say bladder over sender gasket. Hopefully it's just somethin loose, 2005 isnt a very ol bladder!
As far s heading to the backcountry? I probably wouldn't. But I'd try to fly around home a bit and burn most o that tank out. Sure is more fun then draining it.

That’s a lot of staining. I’d want to get that at least isolated before flight. If it’s a bladder, it could/will get worse at the least appropriate time.

MTV

I've been through the leak situation, but in aluminum tanks. Both were cracked on top from "oil-canning". In each case the leak only showed when the tanks were filled, but the staining was not all that different from what your picture shows. Then after I'd spent beau coup bucks getting both fixed (the fix was cheap, $50/'tank; the removal and reinstallation of the tanks was the pricey part), a few months later it seemed to happen again--fill the tanks, and bad fuel staining again. This time, though, it was a $1.29 gasket for the fuel gauge sending unit. Whew!

If it were mine, I sure wouldn't go into the back country with it. I'd be draining the tank and look for the leak, which may very well be due to the reinstallation of the drain. But with my fuel gauge sending unit leak memory, I'd look there first.

Cary

Frankenflaps wrote:

20180826_174143.jpg

I would appreciate some opinions on whether to fly with a seemingly slight? fuel leak from my left wing sump drain. The plane is a Cessna 182P. The drain stem was removed to drain fuel when the fuel selector valve required repair a month ago. It seems the leak could be the seal. The tanks are nearly full and I had planned to fly out to the backcountry for a day. I would like to fly, use up the fuel and then tend to the leak. I have included a photo. There is not enough of a leak to collect on the ground. It seems to just stain the areas shown. There is no fuel smell inside the cockpit. Do you think it is safe or advisable to fly for a day, deplete the fuel and then effect repair? Thank you.

Pretty sure that's the bladder. I probably would error on the side of caution and get it repaired before it flies again.

If it was my bird I'd stick a finger in the tank while changing the o-ring to see if a new seal on the drain valve stopped the leak. If not, canx your trip. 10 minutes worth of troubleshooting for more perfect information.

Fire is an EP I really don't want to deal with. I'd call the plane "unairworthy" and ground it until the leak is fixed. I've seen the results of a couple of fuel fires. Not pretty, and the fire grows FAST!

I’d say that leaking is while the airplane is sitting. I have a drain valve like that that is leaking slightly (It’s a Saf-Air) and I just ordered a new pair from a Spruce. The valve sometimes doesn’t seal tightly after I check for water and I’ve had one leak in flight but the fuel is spread out in a narrow arch behind the valve and looks like “spray”. I would say that if no fuel is dripping on the floor then it’s a bladder leak. It however could be where the fitting for the drain gets clamped inside the rubber nipple on the bladder. It’s just a stainless automotive style hose clamp.

If it isn't making a puddle, it's probably slow enough that you won't have fuel starvation issues - but remember the stuff also evaporates quickly. It could be several things causing that, from a bad bladder to a simple O-ring, though the amount of it around the wing root suggests that it might be higher up (or more internal) than the O-ring under the wing. Mine looked a bit like that and most of it was coming from a bad cork seal on the filler neck, so every time I filled the airplane some would seep out slowly and run everywhere in the vicinity. I say "most" because I also ended up having a tiny bladder issue, but mine were from the 70's. 2005 should be well within the lifespan of a bladder, so check the easy stuff first.

Also get a 90-degree screwdriver and try tightening the screws holding in the fuel sender up behind that root fairing. It's very common to have one of those work loose over time and start to leak.

A leaky fuel sending unit gasket can show stains like that, as well as a leaky nipple. Both are so common. The latter is especially common if the wrong lube is used to assemble the nipple to fuel line connection. That would be my bet given the year of the last bladder change.

Sometimes an otherwise good bladder will develop a small weeping leak near the forward inboard area. There is usually no snap there to hold the bladder up, and therefore the tank sags in that area when not completely full, causing a crease which flexes then leaks. If this is the case, when you drain or burn off as little as five gallons on that side the leak will stop.

If you do have to change a bladder its not as bad as you might think, especially if you have long range tanks with two access holes.

PM me if you need more info.

Ron

How difficult is it to change the sender gasket ,I guess both tanks must empty ,

So, what was your decision? If a mechanic took a look at it, what was the expert's take?

FWIW, I wouldn't accept the risk of an in flight Fire.

Frankenflaps wrote:

20180826_174143.jpg

I would appreciate some opinions on whether to fly with a seemingly slight? fuel leak from my left wing sump drain. The plane is a Cessna 182P. The drain stem was removed to drain fuel when the fuel selector valve required repair a month ago. It seems the leak could be the seal. The tanks are nearly full and I had planned to fly out to the backcountry for a day. I would like to fly, use up the fuel and then tend to the leak. I have included a photo. There is not enough of a leak to collect on the ground. It seems to just stain the areas shown. There is no fuel smell inside the cockpit. Do you think it is safe or advisable to fly for a day, deplete the fuel and then effect repair? Thank you.

dez180 wrote:How difficult is it to change the sender gasket ,I guess both tanks must empty ,

You only need to empty the tank that you need to change the gasket on, just don't put the selector on both and it won't crossfeed. Then the headliner has to get opened a bit so you can pull the sender out and change the gaskets.

Just a general tip I've found from draining fuel, the fuel strainer is a surprisingly easy way to drain the last few gallons you can't easily siphon out.