Fuel Quantity Indicating System - Piper Comanche PA-24 Service Manual

PIPER COMANCHE SERVICE MANUAL
not have these tabs, though installation is similar. The fasteners may be felt through the rubber cell and by
gripping the cell skin with the fingers around the fastener area they may be installed in their bracket. To
check if each fastener is secure reach between the cell and wing exerting a slight pressure inward.
e. Attach the fuel lines to the molded nipple fitting and secure.
f. Make fmal inspection prior to closing the fuel cell to make sure the fuel cell is clear of foreign matter
such as lint, dust, oil or any other installation material. If the fuel cell is not completely clean, wipe it with a
lint-free cloth soaked in alcohol or kerosene.
g. Position the sender unit andlor filler unit with its gasket and install the vent and drain hoses. Align
the bolt holes and insert all bolts before tightening. Torque the bolts according to requirements placarded on
the cell. Special attention should be given to the bolt and stud lengths to avoid bottoming on the inside of the
blind tapped holes or dome nuts.Either of these conditions could produce an error which would result in a
loss of compression of the sealing surface.
h. Connect the sender unit wires and replace the cover plate(s), gasket(s) and screws.
8-10. Fuel Quantity Indicating System.
8-IOa. Check and Adjustment of Fuel Quantity Indicating System.
NOTE
The fuel quantity values in the following procedure include unusable fuel.
a. General Checks of System.
' . . 1. Completely drain the main and auxiliary fuel cells that relate to the gauge that is to be checked.
(Refer to Draining Fuel Cells, Section II.)
2. Level the airplane longitudinally and laterally. (Refer to Leveling, Section II.)
3. Connect a 14-volt power supply to the airplane electrical system and observe the fuel quantity
gauge. It should read empty with the respective fuel selector lever at both the main and auxiliary ON
positions.
4. Add fuel to each cell in the amount of 3.75 (or 8.75 in the PA-24-400 only) U.S. gallons to the
auxiliary cell and 7.5 U.S. gallons to the main cell, to bring each cell to one-quarter its full capacity.
5. Again move the selector lever to both ON positions and observe the gauge. At either position the
quantity pointer should align with any part of the one-quarter full gauge index.
6. Continue to add fuel in increments of 3.75 (or 8.75 in the PA-24-400 only) and 7.5 U.S. gallons
to the auxiliary and main cells respectively for each quarter capacity of the cells. At each quarter increment,
until full, check that the quantity pointer aligns with any part of the corresponding index, with the selector
lever at either ON position.
7. Should the gauge and the amount of fuel in the cell not correspond, the procedure in steps "b"
through "d" may be necessary to isolate the trouble in the system.
b. Sender Check.
l. Remove the fuel sender to be checked. (Refer to paragraph 8- lOb.)
2. Secure the sender in the appropriate position on the fabricated jig as shown in Figure 8-9. (The
jig may be fabricated from dimensions given in Figure 8-19.)
3. With the float arm against the bottom stop, the float should be just touching the base of the jig. If
the float arm is not touching the base of the jig or the bottom stop, adjust the float by bending the arm at a
position shown in Figure 8·9.
Revised: 8115198 FUEL SYSTEM
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