Frequently Asked Questions about Fuel Cells

How do I know if my fuel cell is repairable?
We can't tell you if your cell is repairable until we see it. However, here are some general guidelines for different fuel cell construction types and their average reparability. Check your fuel cell against this list to get a better idea of your cell's potential reparability.

Goodyear/Engineered Fabrics Corporation — Urethane (Vithane)

US Rubber/Uniroyal — All Rubber

Other manufacturers: Aerazur, FTP Industries, Superflexit, Yokohama

Are there different types of fuel cells?
Fuel is stored in aircraft in three different ways.

1. Metal tanks that are manufactured and placed in the cavity (i.e., the Cessna 172).
2. Wet wing or integral tanks. This system is utilized in some general aviation aircraft but is more prevalent in commercial aircraft. The cavity is sealed with urethane or polysulfide sealant to hold the fuel in the cavity.
3. Bladders (or fuel cells) have been the staple way to store fuel in general aviation aircraft. The bladder is removable (for repair) and holds the fuel in a collapsible tank in the event of damage to the cavity.

FFC manufactures many bladder type fuel cells and is certified to repair all general aviation and commercial bladder type fuel cells. In addition, FFC repairs commercial aviation wet-wing cells, and, in the very near future, Mooney wet wing and Piper Cherokee (PA-28 & PA-32) wet-wing cells. For more information, call us today at 1-800 647-6148

How are fuel cells manufactured?
Fuel cells are manufactured by combining two or more layers of material, creating an inner liner bonded to an outer liner. The inner layers should be non-porous and resistant to fuel and fuel vapors. The outer layer protects the cell from heat and humidity. The preferred material for bladder type fuel cells is vulcanized (autoclave cured) nitrile rubber compound.
All fuel cells manufactured by FFC are autoclave cured nitrile rubber cells certified by the FAA. For more information on our manufacturing and repair processes, click here.

How long do fuel cells last?
A new PMA fuel cell or even a properly repaired fuel cell by a certified repair facility should last you for many years — more than 20 years is not uncommon. But it really depends on factors such as environment and operating conditions. A tank that is kept topped off with fuel is more likely to have a long life. Overhauled cells can save you from 25%-60% of the costs of a new fuel cell and, properly cared for, should perform at the same quality as a new fuel cell.
FFC can diagnose your fuel cell for reparability and offer you a quick exchange program whereby we instantly ship you a rebuilt cell of your part number before receiving your damaged cell. Upon receipt of the damaged cell (same part number) and finding that it is repairable, we will refund your core price. For more information, call FFC at 1-800-647-6148.

Vithane (urethane) Cells: PMA replacement vithane fuel cells are currently manufactured only by Engineered Fabrics Corporation (EFC). The only GA aircraft manufacturers currently using bladders in their aircraft are Raytheon with the Beech line and Piper with the aircraft they are currently manufacturing. Both manufacturers use EFC as their tank supplier.
FFC offers every model of Beech aircraft fuel cell. For more information, click here.

Commercial Aviation: EFC is by far the largest manufacturer of commercial aircraft fuel cells using their Vithane technology. These tanks are prevalent in Boeing and Douglas aircraft, as well as many military aircraft. The only other manufacturer competing in this market is American Fuel Cell and Coated Fabrics using nitrile rubber technology.
FFC is the only stocking distributor of EFC PMA Douglas fuel cells. For more information, click here.

What methods might be used for fuel cell repairs, and are those methods approved by the FAA?
This is a general listing of fuel cell repair methods.
All repairs made by FFC will be certified and FAA approved. For more information on our repair process, click here.

Heat cured factory repairs: For the most part, approved by both the FAA and the fuel cell manufacturer. Performed by factory-trained technicians.
Air cured field repairs: Approved by the FAA and the fuel cell manufacturer for emergency repairs. May be performed by A&P mechanics. Not recommended for permanent repairs. Repair kits not always available for construction types.
Coatings: Some approved by the FAA. Performed with FAA authorization in an FAA approved CRS only. Only one repair station still coating.
Do-it-yourself jobs: No approvals.

Why is it important to let a CRS (Certified Repair Station) handle my fuel cell problems?
An approved fuel cell repair facility can properly diagnose your fuel cell problem, including location of leaks and weak areas that might turn into leaks in a few months. Skilled technicians can repair practically any damage to a fuel cell and replace nipples, gaskets, transfer ports, etc returning the cell to FAA certified condition.
All repairs made by FFC are FAA certified and guaranteed unconditionally for two years. To find information on your aircraft, click here.

What is the proper use and care of aircraft fuel cells?
Fuel cells should be topped off as much as possible to keep the fuel cell supple. Because fuel cells are adversely affected by extreme heat and humidity, hangar storage is best whenever possible. There are no inspection requirements for fuel cells. However, if a fuel cell is removed from an aircraft for any reason, it is wise to have it tested and inspected by a CRS (certified repair station).
FFC is designated CRS TH4R544M. For more information on FFC's certifications, click here.

Store cells at room temperature with little or no humidity. Cells should be stored in their original shipping containers. If a cell is removed from its shipping container for inspection, put it back into the container as it was originally folded.

Why is it important to keep my aircraft in a hangar if possible?
Heat and humidity can cause fuel cells to dry out if the tanks are not topped off frequently. This drying out, or brittle condition, is one of the major causes of leaking fuel cells. If you live in a particularly hot and humid climate, it is important to keep your fuel topped off if your aircraft is parked outside of the hangar for extended periods of time. Also, aircraft that has been parked outside during the winter season are susceptible to accumulation of water in the tanks, which is a major cause of bladder failure.