General Description; Purpose Of Equipment; Physical Description; Functional Description - Mid-Continent Instruments 4300 Series Installation Manual And Operating Instructions

Section 1: General Description
1.1

Purpose of Equipment

The Model 4300-XXX Electric Attitude I ndicator with Battery Backup incorporates a moving
display that simulates the earth's horizon and provides the pilot with a real time visual indication
of the aircraft pitch and roll attitude relative to the indicator symbolic airplane.
The instrument can function as a primary or standby indicator with special configurations
available to match existing systems or electronic flight displays. I n the event aircraft electrical
power is lost, the indicator will switch to an internal backup power source (rechargeable sealed
lead acid battery) to permit continued operation of the indicator. Panel tilt, lighting color/ voltage,
non-trimmable knob cover, front mount adapter plates and a slip indicator are available as
options.
1.2

Physical Description

The 4300-XXX Electric Attitude I ndicator with Battery Backup incorporates pitch and roll displays
that are mechanically linked to a spinning mass gyroscope. The horizon bar moves behind the
symbolic airplane. Precession error is corrected by the 4300's erection system or by pulling the
"PULL TO CAGE" knob. I f the gyro motor is not receiving sufficient power to operate, a warning
flag drops into view. This will normally occur only if the unit is turned off or after the internal
standby battery is exhausted.
1.3

Functional Description

Model 4300-XXX Electric Attitude I ndicators employ an efficient electrically driven internal vertical
gyroscope assembly incorporating a special air erection mechanism. This mechanism
simultaneously erects the pitch and roll axes of the gyroscope. Movement of the aircraft
generates a reaction of the display that simulates the visual reference seen by the pilot when
looking outside at the earth's true horizon line.
The 4300-XXX Electric Attitude I ndicator with Battery Backup offers the unique feature of a self-
contained standby power source. Advances in the design of this gyro system allow it to operate
for about one hour after main input power is lost, depending on the battery condition at the time
of power failure.
Anytime aircraft power is absent, with the unit in either power loss warning mode or turned off,
pushing the STBY PWR button will put the unit into the standby power mode. The instrument will
run from standby power until the internal battery is exhausted. I f the unit is already running on
standby power (internal battery), pushing the STBY PWR button will turn the unit off completely.
Pushing the STBY PWR button again will restore unit operation to standby power. Restoring
aircraft power will clear any standby power mode and automatically resume standby battery
charging.
The indicator will operate on an input voltage of 10 to 32 volts. An integral lighting system
featuring a user replaceable light tray assembly operates from the aircraft lighting bus and is
available in 5V, 14V, or 28V versions (dependent on configuration). I n standby power operation,
low intensity LED dial lighting is automatically turned on to provide nighttime visibility.
The internal battery is designed for emergency use only. Frequent use, extended discharging,
extended lack of charging, misuse and age will require battery replacement. Replacement can be
done in the field with or without removal of the attitude indicator. Do not operate this model
Rev J, September 1, 2009
Mid-Continent I nstruments, Wichita, KS
Manual Number 9015762 Page 5 of 22