Specifications

AC 43.13-1B CHG 1 9/27/01
Page 11-12 Par 11-35
11-35. ACCEPTABLE MEANS OF
CONTROLLING OR MONITORING THE
ELECTRICAL LOAD.
a. Output Rating. The generator or al-
ternator output ratings and limits prescribed by
the manufacturer must be checked against the
electrical loads that can be imposed on the af-
fected generator or alternator by installed
equipment. When electrical load calculations
show that the total continuous electrical load
can exceed 80 percent output load limits of the
generator or alternator, and where special plac-
ards or monitoring devices are not installed,
the electrical load must be reduced or the gen-
erating capacity of the charging system must
be increased. (This is strictly a “rule of thumb”
method and should not be confused with an
electrical load analysis, which is a complete
and accurate analysis, which is a complete and
accurate of the composite aircraft power
sources and all electrical loads) When a stor-
age battery is part of the electrical power sys-
tem, the battery will be continuously charged
in flight.
b. The use of placards is recommended
to inform the pilot and/or crew members of the
combination(s) of loads that may be connected
to each power source. Warning lights can be
installed that will be triggered if the battery
bus voltage drops below 13 volts on a 14-volt
system or 26 volts on a 28-volt system.
c. For installations where the ammeter is
in the battery lead, and the regulator system
limits the maximum current that the generator
or alternator can deliver, a voltmeter can be in-
stalled on the system bus. As long as the am-
meter never reads “discharge” (except for short
intermittent loads such as operating the gear
and flaps) and the voltmeter remains at “sys-
tem voltage,” the generator or alternator will
not be overloaded.
d. In installations where the ammeter is
in the generator or alternator lead and the
regulator system does not limit the maximum
current that the generator or alternator can de-
liver, the ammeter can be redlined at
100 percent of the generator or alternator rat-
ing. If the ammeter reading is never allowed
to exceed the red line, except for short inter-
mittent loads, the generator or alternator will
not be overloaded.
e. Where the use of placards or moni-
toring devices is not practical or desired, and
where assurance is needed that the battery will
be charged in flight, the total continuous con-
nected electrical load should be held to ap-
proximately 80 percent of the total generator
output capacity. When more than one genera-
tor is used in parallel, the total rated output is
the combined output of the installed genera-
tors.
f. When two or more generators and al-
ternators are operated in parallel and the total
connected system load can exceed the rated
output of a single generator, a method should
be provided for quickly coping with a sudden
overload that can be caused by generator or
engine failure. A quick load reduction system
or procedure should be identified whereby the
total load can be reduced by the pilot to a
quantity within the rated capacity of the re-
maining operable generator or generators.
11-36. ELECTRICAL LOAD DETER-
MINATION. The connected load of an air-
craft’s electrical system may be determined by
any one or a combination of several acceptable
methods, techniques, or practices. However,
those with a need to know the status of a par-
ticular aircraft’s electrical system should have
accurate and up-to-date data concerning the
capacity of the installed electrical power
source(s) and the load(s) imposed by installed
electrical power-consuming devices. Such