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Instrument Flying Handbook
Emergency Operations
Aircraft System Malfunctions

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Instrument Flying


Table of Contents

Chapter 1. Human Factors
Chapter 2. Aerodynamic Factors
Chapter 3. Flight Instruments
Chapter 4. Section I
Airplane Attitude Instrument
Using Analog Instrumentation
Chapter 4. Section II
Airplane Attitude Instrument
Using an Electronic Flight

Chapter 5. Section I
Airplane Basic
Flight Maneuvers
Using Analog Instrumentation
Chapter 5. Section II
Airplane Basic
Flight Maneuvers
Using an Electronic Flight

Chapter 6. Helicopter
Attitude Instrument Flying

Chapter 7. Navigation Systems
Chapter 8. The National
Airspace System

Chapter 9. The Air Traffic
Control System

Chapter 10. IFR Flight
Chapter 11. Emergency

Ammeter (left) arid Loadmeter (right).
Figure 11-4. Ammeter (left) arid Loadmeter (right).

Alternator/Generator Failure
Depending upon the aircraft being flown, an alternator failure
is indicated in different ways. Some aircraft use an ammeter
that indicates the state of charge or discharge of the battery.
[Figure 11-4] A positive indication on the ammeter indicates
a charge condition; a negative indication reveals a, discharge
condition. Other aircraft use a load meter to indicate the load
being carried by the alternator. [Figure 11-41

Sometimes an indicator light is also installed in the aircraft to
alert the pilot to an alternator failure. On some aircraft such
as the Cessna 172, the light is located on the lower left side
making it difficult to see its illumination if charts are open
Ensure that these safety indicators are visible during flight.

When a loss of the electrical charging system is experienced,
the pilot has approximately 40 minutes of battery life
remaining before the system fails entirely. The time
mentioned is an approximation and should not be relied upon
as specific to all aircraft. In addition, the battery charge that
exists in a battery may not be full, altering the time available
before electrical exhaustion occurs. At no time should a pilot
consider continuing a flight once the electrical charging
system has failed. Land at the nearest suitable airport.

Techniques for Electrical Usage
Master Battery Switch

One technique for conserving the main battery charge is
to fly the aircraft to the airport of intended landing while
operating with minimal power. If a two-position battery
master/alternator rocker switch [Figure 11-5] is installed, it
can be utilized to isolate the main battery from the electrical
system and conserve power.

Operating on the Main Battery
While en route to the airport of intended landing, reduce the
electrical load as much as practical. Turn off all unnecessary
electrical items such as duplicate radios, non-essential
lighting, etc. If unable to turn off radios, lights, etc. manually,
consider pulling circuit breakers to isolate those pieces of

equipment from the electrical system. Maximum time of
useful voltage may be between 30 and 40 minutes and is
influenced by many factors, which degrade the useful time.

Loss of Alternator/Generator for Electronic Flight

With the increase in electrical components being installed
in modern technically advanced aircraft, the power supply
and the charging system need increased attention and
understanding. Traditional round dial aircraft do not rely
as heavily on electrical power for the primary six-pack
instrumentation Modern electronic flight displays utilize the
electrical system to power the AHRS, ADC, engine indicating
system (EIS), etc. A loss of an alternator or generator was
considered an abnormality in traditionally equipped aircraft;
however, a failure of this magnitude is considered an
emergency in technically advanced aircraft.

Double Rocker Switch Seen on Many Aircraft
Figure 11-5. Double Rocker Switch Seen on Many Aircraft