The refurb on my 54' C-180 continues ...
Today I moved on to L/H fuel tank replacement.
The new tank has an outboard fwd upper fuel vent nipple, which is apparently an upgrade on the early model Cessna. Looking for advice on the installation of this vent system. It looks like I will need to cut a new inspection panel in the bottom of the wing, drill a hole in the outboard rib for the nipple, and have a hole by the strut attach zone. There must be instructions out there somewhere. Suggestions welcome ...
Thanks

I think you have it figured out as far as a new inspection hole and figure out where to make the nipple hole. Someone told me that if you don't want to go with the updated vent system you could just plug that nipple and keep doing what was original or if you want to do it right, here is the kit from McFarlane Aviation. If you want to keep it original and can reach, you could probably make the nipple hole from the inside and skip the new inspection hole for the time being.
http://www.mcfarlane-aviation.com/Produ ... C0716122K&

If you PM me your email address I can send you a copy of the instructions. It is worth noting that the original Cessna letter has a misprint on one of the hole sizes, which will lead to a rib repair

Take care, Rob

As I understand it, if you replace the left tank you have to do the vent SK180-6.

The service kit is not available any more and the price would be astronomical if it were.

Here's my plan of attack: I purchased a copy of the SK paperwork including the part numbers from 180/185 Association and have been collecting parts for the time when the enevetable happens. My tank is original 1955.

The valve assembly p/n 0716125 is the most expensive part. I found one from Texas Air Salvage. They had two. I would suggest snapping up the other if you can for the $175 they were asking. McFarlane has an upgraded p/n 0716122 vent tube that comes with a small length of fuel line you'll need and the wing grommet for the vent penetration. That's another $125. The next spends item is the doubler and cover plate. I just happen to have bought these items in a package of three. I'd be willing to sell a pair if you can't find them. They are p/n 0710100-2 and 0311516-8 respectively. The balance of parts are small (clamps, rivets, screws, etc.)

The paperwork I bought from the 180/185 Association is cheap so I'd suggest buying it from them and you'll have the directions and dimensions for the opening you have to cut.

Or you could just take the airplane to Beegles. Just my .02 worth.

Rich

Rob wrote:If you PM me your email address I can send you a copy of the instructions. It is worth noting that the original Cessna letter has a misprint on one of the hole sizes, which will lead to a rib repair

Take care, Rob

Rob,

Would you care to share which one?

Regards, Rich

When I bought my 180, the owner included some tubing and stuff for this vent "upgrade". Told me that it was mandatory if I pull the LH bladder out. I don't believe that SB's are mandatory for a non-commercially part 91-operated airplane. I have never had a problem with the over-cabin fuel vent in a year and a half of owning this 180, or in about 11 years of owning a 170. But I have heard plenty of tales of woe about the under-wing vents dripping, causing uneven- LH & RH fuel flow, etc. I personally don't see any advantage in the underwing vent, except *possibly* being more icing resistant in icing conditions (not generally an issue for a VFR airplane), and I plan on leaving that fuel vent right where it is.

I thought there was an AD. Hmmm, doing the annual tomorrow so I'll find out what my IA says when he does the AD search.

I know my C182 would drip occasionally, but with the vent assembly sitting at the high point of the tank for a tail dragger I would assume the 180 would be less prone to dripping.

I like the idea of not having to cut an access hole in the bottom of the wing.

Rich

Rich, if the vent mod was worth doing, Malcolm probably would have done it already.

I replaced my right bladder a few years ago with an Eagle. Since it wasn't too bad, I thought about doing the left since it is ancient. I tried to get Eagle to make me one without the new vent nipple and he said there was no way he'd send one out that wasn't updated. I decided to keep the old one which is legal until it needs to be replaced.

In reality, it'd be so much better to just put a short plastic airfoil deal in front of the overhead vent to deflect water,ice, and bugs.

AD 90-21-8 requires the modification of the fuel vent by SK 180-6 "any time the left fuel bladder is removed for any purpose". Until the fuel bladder is removed the AD is complied with by the installation of a placard requiring inspection of the fuel vent system. Whether the vent mod is "worth doing" is immaterial to the legality of complying with the AD. Installation of a fuel bladder without the vent modification would be a clear violation of the FAR's by the aircraft owner/operator and the installing mechanic (note installation of a fuel bladder is not preventative maintenance a requires at the very least the supervision of a certificated mechanic).

For FAR part 91 operations SB compliance is not mandatory EXCEPT when included as part of an AD, which is the case where SK180-6 is included in paragraph (b) of the AD method of compliance.

Didn't know it was made mandatory by inclusion in an AD, shame on me.

hotrod180 wrote:Didn't know it was made mandatory by inclusion in an AD, shame on me.

That's OK, just trying to keep the information accurate for future readers of this post.

Tim

Here's a link to the text of the AD being discussed (90-21-08):

http://rgl.faa.gov/Regulatory_and_Guida ... t=90-21-08

From that AD:
"To preclude undetected fuel loss on airplanes equipped with an over the wing (above cabin top) fuel vent tube, accomplish the following:"

and

"(b) When the left fuel bladder is removed for any purpose, modify or install a fuel tank (bladder) equivalent to Cessna Part Number 0726000-13 (fuel vent in the outboard end of the fuel tank container), and relocate the primary fuel vent opening to behind the left lift strut in accordance with Cessna Service Kit SK 180-6. (Under the wing primary fuel vents behind both the left and right wing lift struts are acceptable). "

However, according to Pitts Driver, service kit SK-180-6 is unavailable. How can the FAA expect people to install something which is no longer available?

Something else from the AD:

"(f) An alternate means of compliance with this AD may be used if approved by the Manager, Wichita Aircraft Certification Office, Federal Aviation Administration, 1801 Airport Road, Room 100, Wichita, Kansas 67209.
NOTE 2: The request should be forwarded through an FAA Maintenance Inspector, who may add comments and send it to the Manager, Wichita Aircraft Certification Office."

I wonder if any has ever had an alternate means of compliance approved, perhaps a fairing in front of the existing overwing vent as described by 180Marty?

180Marty wrote:.... or if you want to do it right, here is the kit from McFarlane Aviation. ....
http://www.mcfarlane-aviation.com/Produ ... C0716122K&

BTW this is not a link to the service kit, it is to a modified vent line with a hump rising above the top of the fuel tank to prevent fuel from dribbling too readily out the under-wing vent.

For those who still have the overhead (quarter turn forward) vent tube.
They originally came with a bug screen in them / on them. Never could find a new one but read that there is a usable screen that comes in some small can of voluble liquid. Can't remember if it was acetone, MEK etc.

hotrod180 wrote:Rich, if the vent mod was worth doing, Malcolm probably would have done it already.

Your right on that. He was meticulous but he is also the one that mentioned the vent issue to me. I think he was happy the left tank never let go. The original tank still isn't showing any issues so I'm not messing with it. I'm just accumulating parts for the inevitable.

Say "Hi" to Malcolm for me when you see him.

Rich

"Or you could just take the airplane to Beegles. Just my .02 worth."

I just got a quote from Beegles to do both tanks and the AD with parts for $8500! ouch!

180Marty wrote:I replaced my right bladder a few years ago with an Eagle. Since it wasn't too bad, I thought about doing the left since it is ancient. .

Wow, you are the first person I've heard not say that it was a major PITA. Any tips?

Wow, you are the first person I've heard not say that it was a major PITA. Any tips?

Guess I'm pretty slim with long arms. Hardest thing was getting the spring snap deals to push up into their holes in the far corners. Was all my finger tips could muster to push without bending backwards.