Water Leaks

[Kyle]

Goood Morning Everyone,

Happy fathers day to all who fill that role

My plane has been out on the ramp since May 1st. This is the first time it has been out of a hanger, and on a ramp in about 16 years. The last few weeks we have had buckets of rain. A few days ago I was poking around the plane and discovered that the baggage compartment carpeting - aft most portion, was soaked with water. Additionally, the side paneling and fiberglass insulation under it, was soaked from the cabin floor up about three inches.

The side paneling was only wet on the area of the baggage compartment. The rest of the cabin, from the back of the rear seat forward to the firewall, and all associated side panels, was dry as a bone. The hat shelf was also very damp but not as wet as the carpet. The carpet in the very back, by the bulkhead was so wet you could wring it out like a facecloth.

The door and window seals are all new, and that area seems to be staying dry. The upper edge of the windshield was resealed with the two part window sealer this past winter and the headliner seems to be dry with no stains.

The wing root has masking tape between the wing and cabin. I'm just not sure how far back along the top it goes.

Can anyone point out common problem areas I should be looking into ??

Thanks in advance,

Kyle T.

[doug8082a]

Hey Kyle,

Given the stance in a three point it's not surprising that the aft end of the carpet is the wettest. You mention the hat shelf being damp as well. Sounds like the water came from above and then ran off the hat shelf onto the floor??? How's the headliner? Any antennas above that area? Old patches from prior antennas? Fuselage beacon? Anything that can leak from above in that area? How about the seals around the rear windows?

I would remove anything that is wet and dry it out. It'll only start to mildew and retaining water against the skin is not a good idea. Pull out the rug, remove the rear side panels, and have a look under the headliner. Just a few thoughts.

I'm busy this coming weekend or I'd pop over and have a look. Maybe I can arrange something mid-week if you are up for it.

[GAHorn]

The windshield is mounted all along it's side/lower edges with felt. Heavy rain has lots of access to the interior. Most of if ends up in the belly and out the belly drains, assuming they're clear and open, but.... The rain runs down the windshield, doorposts, etc., and soaks the floor up front along the side panels which "wick" up lots of moisture. The front door-edges allow water to enter unless they are very well sealed by doorstrip/weatherstip. The wing-root vents also allow rain to enter if it blows hard. The water then runs back to soak the baggage carpet.
The wing root is difficult to seal up. Unlike later models, the 170's fairing doesn't completely unwrap from the root, and makes it difficult to tape up the gap, so rain enters the cabin due to capillary action. The "shoulder-blade" fairings are notorious for this, and some of them can be found full of water for days after a rain. (After many years the lower seams become blocked with dirt/dust which make them behave like a full bladder. Use a fiber straw or broomstraw to clear out the lower seams so they can drain externally.)

(My old 206 sat outside most of it's life and I actually found that many bulkheads in the belly bacame water-tanks after a rain. I had to drill drain holes in each bay with a 1/8" bit. Be careful if ever you do this not to hit internal structure, fuel/brake lines, wiring, etc. I've not seen 170's with that particular problem, however.)

[Kyle]

As an update to what I have found. Today it was raining like heck on the Cape so off to the airport I went, flashlight in hand to have a look at the water coming in.

Water is coming in above the bulkhead assembly at Sta. 90.00 on the co-pilots side. The skin lapjoint at this location is the only one in which the skins (Figure 17 Fuselage Assembly, Illust. #18, part # 0512000-73) front leading edge goes on top of the aft edge of the next fwd. skin (Illust. #1, part # 0591200-56).

In all other skin lap joints, the aft section of one skin goes over the forward edge of the next skin as you work your way aft to the tailcone.

When viewed from the inside, the headliner was wet, right at sta. 90.00 bulkhead above the leading edge of the hatshelf. The problem is when viewed from outside / above, that portion of the lapjoint is covered over by the wing fillet assy. (Figure 17 - item 10, part # 0512153-2)

In addition, I removed the baggage cmpartment rear panel and got my head up to look forward thru the upper holes of the sta. 108 bulkhead. I observed water droplets on the sta. 90 bulkhead. I think next is to remove the headliner - need to figure out how without tearing / ripping etc.

Lastly, my grimes rotating beacon, mounted on top between bulkheads 108 and 140 is also leaking .....

Be gone for a few days but appreciate any comments or sugjestions ?

Thanks in advance.

[GAHorn]

The beacon leak shouldn't affect too much as regards soaking the interior, due to it's aft location.
The skins tho' don't seem right.
I'm not where I can just go out to the hangar and look at my airplane, but I don't think I recall any of the skins being installed underneath subsequent skins( fore-to-aft) like you describle your sta. 90.
If indeed your airplane is so assembled, (maybe a rebuild error?) then the only way I can imagine to stop the leak (other than a pretty big job of drilling it apart and reskinning) is to use Pro-Seal along that seam. Lots of heavy iron use that technique, and it can be unnoticeable if done correctly. Clean the seam with Alcohol and let it dry thouroughly so no alcohol is in the seam. Mask off the seam about 1/8" fore and aft of the seam, and spread the Pro-seal, ... then, after it's tacky, but before it hardens, strip off the masking tape.
You'll likely have to paint it to match. (Pro-Seal might also seal up around the mounting ring around the beacon?)

[Kyle]

George,

I went back out today and had a look at the seam. False alarm ... the lap joint is just like the rest of them. Properly overlaped so as not to cause water or anything else to be forced under. Don't know what I was thinking ..... to many hours at whatever

I believe I will still need to pull the headliner down to see where it is coming from.

If anyone has had experience in dropping the headliner, any tips would be appreciated.

Thanks in advance ..........

[GAHorn]

Kyle, do you have any antennas on top of the cabin? If so, water can leak under a dry/cracked/missing gasket and can run underneath for quite a ways following skin, cables, etc., until it finds a place to drip off.
If you have single-element antennas, such as the type that penetrate the cabin roof via porcelain insulators,...they can be the worst. The local NAPA will sell you some 1/8" sheet of cork gasket material which you can make gaskets out of.

[blueldr]

Another way to effectively seal lap joints and similar leaks is to heat the area with a heat gun and flow some parafine or candle wax in to the leaking area.

[GAHorn]

Another way to effectively seal lap joints and similar leaks is to heat the area with a heat gun and flow some parafine or candle wax in to the leaking area.

Pep Boys sells candles? (What a great idea! But mightn't those items might also melt in the sun and drip onto the headliner?)

[Bruce Fenstermacher]

Yes BL this tip might make reading your posts worth it.

(OK that was uncalled for, but my fingers are bad and I couldn't stop them from typing. I do enjoy your view on many subjects BL)

So tell us how the wax holds up to the heat of the sun.

My plane to had a very wet rear compartment. I found that when it rained the prevailing winds blew the rain under the upper fairing between the wing and the flap and into the fuselage at the cable pass through holes. Since I couldn't and didn't want to move my plane tie down I removed those panels and sealed them with silicone. effectiively removing most of those leaks

[170C]

Personally I perfer the water leaks to oil leaks , but I too had water leaks and at last years convention in Detroit when we were ready to leave the headliner was wet over the rear seat on the left side and all the way from the back seat to the door post ahead of the fuel gauge on the right side Upon a suggestion on this forum I removed the two panels over the flap cables as mentioned above and put some silicon on the seams. It appears (hopefully) that that cured the problem. Hope yours goes as well.

[GAHorn]

I like to stay away from "silicone" sealants whenever possible because they contribute to corrosion due to curing agents... but I guess a wet interior is worse.
I wonder if the flap/fuselage fairings are draining well? They tend to fill their lower seams with dirt and then the water level builds in them and can flood the interior. Flushing them out should avoid this.
My own airplane has withstood quite heavy rain (including the entire week of rain at the Wilmington convention) and remained dry inside. But the following trip home involved a stay on Dauphin Island when a mini-hurricane absolutely flooded the carpet. I believe that water penetrated thru the open air vents and down the front doorposts. I aired the airplane out with the carpet raised for quicker drying, and haven't experienced it since. (But I also make certain my air vents are tightly closed when tied out.)
Another oft-overlooked source for wet interior is the upper windshield seam. Water will penetrate that unsealed area and drip down onto the carpet. Duct tape might help diagnose it.

[Bruce Fenstermacher]

I didn't want to use the silicone for the possible corrosion problems you mentioned George but couldn't think of anything else to use.

That is why I was so intrigued with BL's suggestion of using parafine wax. It is so simple if it doesn't melt out from the suns heat.

[Kyle]

Thanks everyone for the hints.

Bruce, when you mentioned "I found that when it rained the prevailing winds blew the rain under the upper fairing between the wing and the flap and into the fuselage at the cable pass through holes. Since I couldn't and didn't want to move my plane tie down I removed those panels and sealed them with silicone. effectiively removing most of those leaks"

Do you mean you removed the wing fillet assy. (Figure 17 - item 10, part # 0512153-2) ?? because I don't see how else to get to that seam. Also the cable pass through holes .... are they under the same fairing or can I get to them by removing the flat acess cover that has 5 screws in it?

George - I have two comm antenna's on top a few inches behind the fuel vent. They are what looks like standard cessna comm antennas. I will check them for seals, however all insulation around then seems to be dry.

The problem area seems to be just aft of the pulleys under that fairing.

I'll report back as soon as we have a chance to look at it. Again.......thanks for all the tips.

[Bruce Fenstermacher]

Kyle
I sealed plate part number 0520007-1 fig 7 #19 which is held in place by 5 screws.