Technical data

13773-001
28-10
Page 1
STORAGE
1. DESCRIPTION
The fuel storage system consists primarily of a vented integral 42-gallon (159-liters) capacity fuel tank in
each wing, a integral fuel collector tank/sump in each wing, a three-position selector valve, an electric
boost pump, gascolator, an engine-driven fuel pump, and five fuel drains.
Each wing contains an integral fuel tank bounded by the upper and lower wing skins, main spar web, aft
wing shear web, and the inboard and outboard fuel tank ribs. The wing skins and fuel ribs, are of fiberglass
composite with foam core sandwich construction. A fuel baffle rib is also integral to each tank to reduce
fuel slosh. Fuel return lines are fed to the top of each fuel tank. Access panels are located in each fuel tank
bay for servicing. Fuel tank fittings and screens are accessible through wing access panels. Fuel flows by
gravity from each fuel tank to the corresponding integral collector tank. Fuel then feeds into a fuel tube
located in the fuselage.
Sumps are built into the fuel tanks and collector tanks. Integral collector tanks are located at the inboard
wing root area of each wing. The collector tank offers a sediment and water collection area, and capacity
for ensuring fuel flow to the engine during uncoordinated maneuvering. A drain is located in each tank for
preflight inspection. The collector tank drains are located at the fuel system low points. The center of the
fuel drains can be pushed inward with the fuel sampler to inspect for water or contaminates. A flapper
assembly (swing check valve) is installed in the line from the wing tanks to the collector tank to keep fuel in
the collector tanks during uncoordinated maneuvers. Each collector tank holds approximately 3.5 gallons
(13.2 liters). The integral collector tank access cover is supported by a continuous flange around the lower
skin opening.
A 1/16-inch mesh strainer is installed on each of the two ports in each integral fuel tank. The strainers are
accessible by removing the inboard fuel tank access cover. The stainless steel strainers are brazed to
stainless steel nuts and are 1.0 inch (25.4 mm) in diameter by 2.5 inches (63.5 mm) long. The fuel strain-
ers in the fuel tanks should always be cleaned after the airplane has been in storage. If any damage or
restrictions are noted during inspection, then replace the strainers.
Each filler cap has a viton o-ring which seals the fitting in the upper wing skin. The filler cap is grounded to
the airframe through a resistive (approximately 100 ohm) connection through the aircraft lightning protec-
tion. Fuel tabs are integrated into the fuel filler necks and indicate approximately 23.0 usable gallons (87.0
liters) in each tank.
Each integral fuel tank is vented from the top of each fuel tank to a flush NACA style scoop vent located
approximately 51 inches from the wing tip on the lower wing skin. Vent lines from the main fuel tanks are
constructed of fuel resistant plastic. The fuel tank vent lines do not have any points in which moisture can
accumulate during normal ground or level flight operation. The top of each collector tank is vented to the
inboard fuel rib of the corresponding fuel tank.
Fuel drains are provided at various locations throughout the fuel system for drainage of water and sedi-
ment from the fuel system. To activate the drain valves, a fuel sampler cup/screwdriver is furnished with
the flyaway kit. Drain valves are located at the inboard access panel of each integral fuel tank, both collec-
tor tanks, and the gascolator.
Note: When servicing fuel system pipe thread fittings, apply a small amount of grease (MIL-G-
60320 Type 1) to the external threads.
30 Nov 2000