Gas Tank Failures

C

cubnut

New member
Just got another report of a gas tank leak. I am guessing here, but it seems like there is a short period of time when factory gas tanks could not handle the rigors of aerobatics? It takes almost eight hours to pull a gas tank, another eight to stick one back in, and at least that long to put all the fabric back on.

My 1977 has never had a failure, but one in the local community got new factory tanks in 2004, and since then three failures!
 
Hello, How do you know the gas tank is leaking? Do you see fuel stains on the wings? Is there a way to inspect the tanks without removing fabric? Thank you!
 
My 2005 8KCAB developed a leak in the LEFT tank at 270 hrs TT. I have flown about 50 hrs of light acro in the aircraft. Acro did not include snap rolls and was done when the fuel tanks were less than 1/2 full.

Indications: Initially Fuel smell in the cockpit. Eventually fuel dripping out of The vent holes in the bottom aft of the wing, and the aft wing root.

Repair for the leak required removing the wing and removing the fabric top and bottom 5 ribs out from the wing root. The tank was leaking from two different places on the aft part of tank near the bottom. The tank could not have been repaired in the wing.

ACA was helpful throughout the process. Shipping and crating costs to the ACA factory from the West Coast were cost prohibitive . I flew the aircraft to a Museum in Port Townsend Wa. that specializes in fabric aircraft for repair. The leaking tank was drained and blocked off from the fuel system for the flight.

There seems to be several incidents of fuel tank leaks in this period of time. As a result,I decided to have the right wing removed and the RIGHT tank replaced as well. Good thing, the RIGHT tank was cracked and beginning to leak too.

This was a very costly and disappointing repair for such a low time aircraft.
 
View attachment 1I had fuel showing up at the back of the wing running down the fusalage after flying. It was worse when the fuel level was high and barely noticable with the tanks on a quarter. So we knew the problem was in the top of the tank. No acro but a 50 year old airplane that certainly has seen acro. The gas was very visible and smelly being mogas vs 100LL.

I called ACA. As you say they were very helpful describing what to do. My A&E and I noticed a fabric stain at the rear corner of the tank and decided to first cut a 4" hole in that location. There it was! A very small crack adjacent to a weld. I could not beleive all the gas was coming from that small crack. We cleaned it and put PPG PRC-DeSoto P/S 890B2 Gray Fuel Tank Sealant on it and I patched the fabric. The second picture is with primer on the patch before it was top coated.

My recommendation would be to fill your tank and begin by cutting a 4" hole or two in stategic locations to look in and see what you can determine. You may be able to seal it in place.

Also being an old plane, the treads in my drain bung were boogered up and would not seal. I Prosealed a brass 1/4"x1/8" bushing in the bung and went to a 1/8" drain valve.
 
my 1964 7ECA started out with some fuel stains back by the drain. I thought it was just a little "weepy". some time later the fabric came loose at the trailing edge. $3,000 later, I'm flying again. What a mess.
 
You must log in or register to reply here.
Back
Top