Fuel System Description; Fuel System Troubleshooting - Piper PA-44-180 SEMINOLE Maintenance Manual

GENERAL.
The fuel system components covered in this section consist of fuel cells. fuel selector valves, gascolator and
electric fuel pumps. Each wing contains a fuel cell, having a capacity of 55 U.S. gallons, for a total capacity of
110 U.S. gallons.
This chapter also provides instructions for removal, repair, cleaning, reassembly and testing of repairable
components of the fuel system.
The aircraft is approved for operation with an anti-icing additive in the fuel. When an anti-icing additive is
used it must meet the specification MIL-I-27686, must be uniformly blended with the fuel while refueling, must
not exceed .15% by volume of the refueled quantity and to ensure its effectiveness should be blended at not less
than .10% by volume. One and one-half liquid oz's. per ten gallons of fuel would fall within this range. A
blender supplied by the additive manufacturer should be used. Except for the information contained in this
section, the manufacturer's mixing or blending instructions should be carefully followed.
ASSURE THAT THE ADDITIVE IS DIRECTED INTO THE FLOWING FUEL
STREAM. ADDITIVE FLOW SHOULD START AFTER AND STOP BEFORE
FUEL FLOW. DO NOT PERMIT CONCENTRATED ADDITIVE TO COME
I N TO CONTACT WITH THE AIRCRAFT PAINTED SURFACES OR THE
INTERIOR SURFACES OF THE FUEL TANKS. SOME FUELS HAVE ANTI-
ICING ADDITIVES PRE-BLENDED IN THE FUEL AT THE REFINERY. NO
F U RTHER BLENDING SHOULD BE PERFORMED. FUEL ADDITIVE
MUST NOT BE USED AS A SUBSTITUTE FOR PREFLIGHT DRAINING OF
THE FUEL SYSTEM DRAINS.
DESCRIPTION.
An independent fuel system is incorporated into each wing permitting each engine to operate from its own fuel
supply. However, the two systems are interconnected by means of a crossfeed that will permit fuel from one cell
to be drawn by the opposite engine in the event of an emergency.
Fuel cells are installed in the aft nacelles and consists of bladder type tanks.
Fuel pressure and fuel flow for each system are indicated on their respective gauges located in the instrument
panel. A fuel quantity gauge for each system, also located in the instrument panel, indicates the amount of fuel
remaining as transmitted by electric fuel quantity sending units located in the wing tanks.
Fuel for each engine is drawn through a finger screen located in the fuel tank to a selector valve. From the
selector valve, the fuel goes through a gascolator (fuel filter) to the electric pump and into the engine driven
pump which forces the fuel to the carburetor.
TROUBLESHOOTING.
Chart 2801, lists troubles which may occur in the mechanical or electrical portions of the fuel system, the
probable cause and a suggested remedy. When troubleshooting, first check from the fuel supply or power source
to the item affected.
PIPER AIRCRAFT
PA - 4 4 - 1 8 0 / 1 8 0 T
AIRPLANE MAINTENANCE MANUAL
— CAUTION —
2A21
2 8 - 0 2 - 0 0
Page 28-01
Revised: May 15, 1989