ATP Electronics Piper Archer - Fuel Management; Electrical System; Alternator Failure

4 • Aircraft Systems
An electric engine priming system is provided to facilitate starting. The primer
switch is located on the far left side of the overhead switch panel.
CAUTION: DO NOT OVER-PRIME. Over-priming washes lubrication
from cylinder walls and increases re risk. Always follow the
checklist for primer usage.
Fuel Management
Throughout operation, checklists will call for "Fuel Selector... Proper Tank." It is
important to monitor fuel burn to maintain a balanced fuel load. The Archer
POH does not provide a limitation on fuel imbalance. It is ATP's policy that
the fuel selector should not be changed during critical phases of ight, to
include takeo and operations below pattern altitude, unless called for on an
emergency checklist.
During cruise ight and maneuvers, fuel load should be monitored and the fuel
selector should be selected to the fullest tank only when a noticeable dierence
in fuel load occurs. 30 minutes of operation should result in a fuel load
dierence of several gallons, and is a good guideline for fuel selector changes.
During pattern work operations, the fuel selector should only be changed while
on the ground during a Full Stop/Taxi Back procedure. It is critical to follow the
proper procedure for changing fuel tanks while on the ground, as well as while
in ight. Failure to follow the proper fuel selector change procedure can lead to
interruption in fuel ow, and engine failure, during a critical phase of ight.
Electrical System
The Archer is equipped with a 28-volt DC electrical system and a 24-volt lead-
acid battery. Electrical power is supplied by a 70-amp, engine-driven alternator.
A voltage regulator maintains a constant 28-volt output from the alternator. An
overvoltage relay is located on the forward left side of the fuselage behind the
instrument panel. Alternator output is displayed on a digital ammeter on the
instrument panel.
Alternator Failure
In the case of the "ALTERNATOR INOP" annunciator, follow the "ALT Annunciator
Illuminated" checklist. The expanded procedure can be found in the Archer POH
Section 3.25:
"Loss of alternator output is detected through zero reading on the ammeter. Before
executing the following procedure, ensure that the reading is zero and not merely
low by actuating an electrically powered device, such as the landing light. If no
increase in the ammeter reading is noted, alternator failure can be assumed. The