Squawk Box

March 2018 Issue

Fuel Tank Frustrations

Cessna 172M Skyhawk
Blocked Vent

Right fuel tank cracked at top seam. Tank was replaced. Operator noticed a very loud oil canning sound from right wing after shutdown following a one-hour flight. Investigation revealed a partial blockage of the fuel tank vent, causing oil canning of fuel tank due to vacuum in fuel tank. Vent line was cleared and vented cap was replaced with new.

Part total time: Unknown


Cessna T207A
Leaking Wing Tank

After several attempts to find a fuel odor in the cabin, the right wing-mounted fiberglass wing tank was removed. Discovered evidence of substantial leakage and other small seeping spots. The leaking tank was replaced with OEM-style fuel bladders. Suspect leaks resulted from the age of the tank and/or porous spots in the fiberglass resin.

Part total time: 2,637 hours

Flight Design CTLS
Unknown Fuel Blockage

During cruise flight, engine went from 5100 rpm to 3000. Transparent fuel tubes at the base of the wings and visible in the cockpit revealed no fuel in left wing tank but adequate fuel in right one. Carb heat, banking into left turn with right wing up had no benefit. Engine quit completely at 500 feet agl. Landed dead-stick. No damage, no injuries. Minutes after landing, engine was restarted and ran fine. Dipstick showed five gallons in right tank, none in left. Later, approximately 3.5-4 gallons of fuel were drained from the sump. Removing wings revealed some residual fuel still in wing tanks.

Part total time: 1,150 hours

Piper PA-34-200T Seneca II
Corroded Wing Tanks

Pilot reported fuel leaking from under right wing deicer boot. Removed boot and found corrosion had eaten through the leading edge of both tanks behind the deicer boot. It’s probable that water was retained behind the boot and created the problem.

Part total time: 5,723 hours

Piper PA-28-161 Warrior II
Contaminated Fuel Tank

Left fuel tank found to have very small black particles in fuel sample. After sumping various times, the small black particles were still present in the fuel samples. Left fuel tank removed to clean foreign debris. Upon removing the fuel transmitter, the carbon float was found to be coming apart on the edges and was rubbing the fuel tank when at extreme up or down travel. Transmitter replaced with new.

Part total time: Unknown