FAA Advisory Circular 43.13-1B
Acceptable Methods, Techniques, and Practices
Aircraft Inspection and Repair
AC 43.13-1B | 8. Engines, Fuel, Exhaust, and Propellers | 2. Fuel Systems | 8-35. Fuel Pumps
9/8/98
AC 43.13-1B
the effects will occur sooner with a full fuel
tank than with one partially filled.
b. Check tank vents and overflow lines
thoroughly for condition, obstructions, correct
installation, and proper operation of any check
valves and ice protection units. Pay particular
attention to the location of the tank vents when
such information is provided in the manufac-
turer’s service instructions. Inspect for
cracked or deteriorated filler opening recess
drains, which may allow spilled fuel to accu-
mulate within the wing or fuselage. One
method of inspection is to plug the fuel line at
the outlet and observe fuel placed in the filler
opening recess. If drainage takes place, inves-
tigate condition of the line and purge any ex-
cess fuel from the wing.
c. Assure that filler opening markings
are affixed to, or near, the filler opening;
marked according to the applicable airworthi-
ness requirements; and are complete and legi-
ble.
8-34. FUEL CROSS-FEED, FIREWALL
SHUTOFF, AND TANK SELECTOR
VALVES. Inspect these valves for leakage
and proper operation as follows.
a. Internal leakage can be checked by
placing the appropriate valve in the “off” posi-
tion, draining the fuel strainer bowl, and ob-
serving if fuel continues to flow into it. Check
all valves located downstream of boost pumps
with the pump(s) operating. Do not operate
the pump(s) longer than necessary.
b. External leakage from these units can
result in a severe fire hazard, especially if the
unit is located under the cabin floor or within a
similarly-confined area. Correct the cause of
any fuel stains associated with fuel leakage.
c. Selector Handles. Check the operation
of each handle or control to see that it indicates
the actual position of the selector valve to the
placard location. Movement of the selector
handle should be smooth and free of binding.
Assure that stops and detents have positive ac-
tion and smooth operational feel. Worn or
missing detents and stops can cause unreliable
positioning of the fuel selector valve.
d. Worn Linkage. Inaccurate positioning
of fuel selector valves can also be caused by
worn mechanical linkage between the selector
handle and the valve unit. An improper fuel
valve position setting can seriously reduce en-
gine power by restricting the available fuel
flow. Check universal joints, pins, gears,
splines, cams, levers, etc., for wear and exces-
sive clearance which prevent the valve from
positioning accurately or from obtaining fully
“off” and “on” positions.
e. Assure that required placards are
complete and legible. Replace those that are
missing or cannot be read easily.
8-35. FUEL PUMPS. Inspect, repair, and
overhaul boost pumps, emergency pumps,
auxiliary pumps, and engine-driven pumps in
accordance with the appropriate manufac-
turer’s instructions.
8-36. FUEL FILTERS, STRAINERS,
AND DRAINS. Check each strainer and filter
element for contamination. Determine and
correct the source of any contaminants found.
Replace throw-away filter elements with the
recommended type. Examine fuel strainer
bowls to see that they are properly installed ac-
cording to the direction of the fuel flow.
Check the operation of all drain devices to see
that they operate properly and have positive
shutoff action.
Par 8-33
Page 8-21