Technical data

13773-001
28-10
Page 2 30 Nov 2000
2. MAINTENANCE PRACTICES
A. Wing Fuel Tank
(1) Adjustment/Test - Wing Fuel Tank Pressure Test
(a) Acquire necessary tools, equipment, and supplies.
(b) Fill each tank with approved fuel. (Refer to 12-10)
(c) Place the fuel selector valve in the off position.
(d) Remove the fuel system vent scoops (NACA vent) from the underside of each wing, next
to the wing tip (LW14 or RW14).
(e) Disconnect vent hoses from the vent scoops.
(f) Plug outboard end of either vent hose.
(g) Connect a rubber hose and tee into the unplugged vent hose.
(h) Attach a water manometer and a low pressure air gage into the tee. The water manometer
will be the primary checking device for pressure measurements. The pressure gage is the
backup gage and will serve as a check on the manometer.
(i) Record the ambient and calculated maximum water pressure and level readings.
WARNING:
Never attempt to remove the fuel filler cap with pressure in the fuel
system. Never apply regulated or unregulated air from an air compres-
sor to the fuel vent hose.
CAUTION: The water manometer will be the primary checking device for pressure
measurements. The pressure gage is the backup gage and will serve as a
check on the manometer. Do not pressurize the fuel tanks to more than
55.4 inches of water (2.0 psi). Major structural damage to the fuel tank/wing
may occur if more than 55.4 inches of water (2.0 psi) is applied. Stop pres-
surizing the fuel system when either gage indicates the maximum allowable
pressure or level. If pressure or level exceeds 55.4 inches of water (2.0 psi),
the fuel system may sustain damage that cannot be repaired. Always blow
into hose, never inhale fuel or vapor. It may take several breaths to reach
55.4 inches of water (2.0 psi). Only air gages that are known to be accurate
shall be used.
(j) Blow into the open end of hose until the manometer indicates 55.4 inches of water (2.0
psi).
(k) Pinch or clamp hose to maintain maximum pressure in the fuel tanks.
(l) Leave the fuel system pressurized for 10-20 minutes.
(m) Inspect fuel and collector tanks, fittings, and caps for signs of leakage.
Description P/N or Spec. Supplier Purpose
Rubber vent hose - Any Source Test fuel system
Tee fitting - Any Source Test fuel system
Air pressure gage 0-5 psi Any Source Verify pressure
Water manometer - Any Source Verify pressure
Soapy water solution - Any Source Inspect for leaks