Fuel tank vent

[km74]

My 170A has a fuel tank vent on the cabin roof. I have heard on a few discussions about people having only one vented fuel tank cap on their airplanes. Do you even need a vented cap on our airplanes? Is it just to have another vent in case that one plugs off? Has anyone had any problems with snow and ice building up inside that tube? It faces forward so you would think it would pick all kinds of debris while taxiing or parked outside and deposit them in the tank via the fuel tank vent. do most of you guys who park outside put a cover on them when parked? Has anyone had any problems with them in the winter with blowing snow? Thanks for any replys?

Ken

I also got my wing and engine covers today from Kennon and they fit pretty good.

[N1277D]

During the ownership of my 170A I have had no problems with the fuel tank vent on the top; even when flying through light snow that accumulated on the struts and stuck to the bottom of the aircraft. I learned somehow that snow tends to accumulate on that oil slim that builds up on the bottom of the aircraft

[doug8082a]

AD 79-10-14 R1 applies to multiple Cessna models including the entire 170 series (s/n 18729 through 27169) and addresses the "problem" of fuel tank vent obstruction. It requires that at least one fuel cap be vented as an alternate venting source should the original vent become blocked.

Personally, I haven't experienced my vent being blocked. I still have the phenolic mast from the old ADF antenna which seems to be doing a good job of keeping bugs out of the vent opening.

Fortunately though, it's one of the easiest ADs to comply with and, with the way the FAA can be up here in the Northeast , I'm better off for having done so.

Doug.
'52 170B

[N1478D]

I took my mast off before I knew that it served a purpose. Have not had a problem with the fuel vent other than small fuel stains sometimes when I take off from short fields with a lot of gas. About 500+ hours and over 4 years, sometimes in rain and have been up to Colorado in it during the winter time without any trouble. Never worry about it when parked outside.

[wa4jr]

Hi Ken...I have a '54 170B parked outside for lack of hangar space. I fly once a week even if only for a short time to keep the engine in good shape. I usually get water out of each tank sump...with more coming from the right tank. Usually 1/8 to 1/4 of the fuel tester is water. Minor amounts from the gascolator. I blame the water intake on the factory fuel vent. My vent has a screen to prevent foreign objects from entering and a check valve to keep fuel from flowing out during "spirited" maneuvers. I just read in the Cessna 170 Book that the origin of the AD requiring vented caps on the right tank of the Cessna 170 is with the Cessnas that had a vent line running out to a wing tip where insects could easily build nests. According to the Cessna 170 Book, there is no record of any Cessan 170 fuel vent failures. The FAA evidently thought that what is good for one specific type of Cessna is good for them all regardless of their fuel venting configuration. The Cessna 170 Book goes on to list a number of fuel system problems that are CAUSED by the required installation of the vented cap our our airplanes. So you can make the call as you see it, Ken. If I can beleive the Cessna 170 Book, our 170s did not have a problem with the fuel venting system, so it appears the FAA dropped the ball on this one. One could probably go back to non-vented caps...the only problem being the legality issue.

[GAHorn]

Hi Ken...I have a '54 170B parked outside for lack of hangar space. I fly once a week even if only for a short time to keep the engine in good shape. I usually get water out of each tank sump...with more coming from the right tank. Usually 1/8 to 1/4 of the fuel tester is water. Minor amounts from the gascolator. I blame the water intake on the factory fuel vent. My vent has a screen to prevent foreign objects from entering and a check valve to keep fuel from flowing out during "spirited" maneuvers. ....

The Service Bulletins/kits that provided additional holes in the rear of the gooseneck and the check valve in the gooseneck were subsequently rescinded due to additional problems introduced by compliance with those kits. It is recommended that they be "undone".
A very likely source of water in fuel tanks of aircraft stored outdoors is the standpipe which is formed by the filler neck leaking water into the tanks. That filler neck is threaded and screwed into the tank well fitting and was supposed to be sealed with sealant. But if not done properly, or if deteriorated, water will collect there and leak into the tanks. Some owners tape a rubber cover over their fuel cap areas while stored outdoors. Alternatively, you could comply with the Monarch system of covering the area.

[doug8082a]

What little water problems I had were solved with the Monarch risers and caps. I doubt the original vent is the source of your water problem. My 170 has been outside for the three years that I've had it (2 years with the Monarch mods) and the only time I get water now is if I fail to fill the tanks after a flight and moisture condenses inside the tank.

Doug
'52 170B

[n1410d]

Just file this under useful information that you will probably never use. I had a chief flight instructor tell me of a time when his fuel vent iced up on a 182 during a flight. The engine started surging and he finally guessed the reason. His solution; he opened the window grabbed his fuel sample cup and stuck it in the drain. Instant vent. It kept him up until he got to the next airport. Moral; keep that sample cup where you can reach it

By the way I have one vented cap (right tank) and one unvented cap. Have never had a problem. IF you ever smell fuel in the cabin especially after a wheel landing, check the rubber hose that connects the main vent to the lines going to the fuel tanks. Mine were leaking but not enough to put a blue stain on my headliner. And check those fuel cap gaskets. If you don't know how old they are replace them. Wag Aero has them. It's one of the few Cheap things you can buy for an Airplane

Patrick Mahaffey. Grand Prairie TX
n1410d

[zero.one.victor]

I like the story about using the tank drain to vent the tank while in-flight. But........
On my 170,first of all,the window won't open enough to get your arm out & up to the bottom of the wing without the window-latch being disconnected.
Second of all,if the latch IS disconnected,when the window is opened in-flight it will float up against the bottom of the wing,covering the tank drain.You can see it (if the window's not too dirty!) but ya can't reach it.
Makes for a good story,anyway! I like the ones about Santa,and the Tooth fairy too!

Eric

[flyer170]

I had fuel stains from my left fuel tank and I fixed that last week with a new fuel cap gasket (pg 51 part #E-422-000) that I bought from Wag-Aero. I replace the oil filler gasket with the same type gasket. My vented cap on the right tank works fine. I have installed a short mast that I made out of wood in the stanchon ahead of the cabin fuel vent.
George and others I still need to plug the two small holes on the back side of the fuel vent tube. What would be an easy way to do that I tried some metal tape but the fuel softened the adhesive on the tape.
Bob

[N1478D]

Just file this under useful information that you will probably never use. I had a chief flight instructor tell me of a time when his fuel vent iced up on a 182 during a flight. The engine started surging and he finally guessed the reason. His solution; he opened the window grabbed his fuel sample cup and stuck it in the drain. Instant vent. It kept him up until he got to the next airport. Moral; keep that sample cup where you can reach it

By the way I have one vented cap (right tank) and one unvented cap. Have never had a problem. IF you ever smell fuel in the cabin especially after a wheel landing, check the rubber hose that connects the main vent to the lines going to the fuel tanks. Mine were leaking but not enough to put a blue stain on my headliner. And check those fuel cap gaskets. If you don't know how old they are replace them. Wag Aero has them. It's one of the few Cheap things you can buy for an Airplane

Patrick Mahaffey. Grand Prairie TX
n1410d

Good Morning Pat,

Your 170 always looks like it has just been waxed, never dirty. Saw you the other day with a long handled contraption working the top of your wings. What's your secret to keeping your plane looking so good?

[GAHorn]

I had fuel stains from my left fuel tank and I fixed that last week with a new fuel cap gasket (pg 51 part #E-422-000) that I bought from Wag-Aero. I replace the oil filler gasket with the same type gasket. My vented cap on the right tank works fine. I have installed a short mast that I made out of wood in the stanchon ahead of the cabin fuel vent.
George and others I still need to plug the two small holes on the back side of the fuel vent tube. What would be an easy way to do that I tried some metal tape but the fuel softened the adhesive on the tape.
Bob

Fast/Cheap/Easy method:
Take a piece of rubber or pvc hose that is a tight fit and insert it into the gooseneck as a dam. Use "JB Weld", two-part epoxy, found at Wal Mart and autoparts stores. Mix it and let it get a little more firm than syrup,...more like putty. Work it into the hole so as to get it plugged without forcing a lot of it into the gooseneck. Smooth the external appearance and remove the rubber tube. Let it harden at least 4 hours before lightly sanding the outside for appearance. Don't try to mess with the inside. (A small "button" formed in there will help hold it in place.)

Correct Method:
Remove the gooseneck and take it to a welder. Reinstall it with new hoses.

[flyer170]

George... Thanks for that info.
Check out my pop quiz under fuel selector above 5,000ft
hangar section.
Bob

[rudymantel]

Speaking of keeping that fuel sampler cup handy, I gotta share this with you guys. I was flying my 336 (fixed gear) Skymaster from Jamaica to Miami one day. I was alone, over Cuba when I got the urgent urge to pee. The only container I had was the little drain cup. The 336 fortunately had a storm window. It was slow and tortuous but eventually the fuel drain cup helped me relieve the problem.
Rudy

[GAHorn]

It's not so tortuous if you'll remove that little spike from the sample cup before trying to pee into it.