Ameri-King АК-451-Series - Manual (Page 9)

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weights and severe penetrator tests, and continue to operate normally. Continued
operation in a temperature range of -20 degrees Celsius to +55 degrees Celsius is
assured.
2.2 OPERATION
The AK-451 ELT, Emergency Locator Transmitter, is a state of the art Micro
controller technology, long lasting, solid state based equipment. It is an extremely
reliable, highest standard of quality, designed to meet TSO-C126 and TSO-C91a
requirements for critical application.
Both ELT main unit and Remote Switch are self-powered by their own internal
batteries. Interface with aircraft electrical power system is not required.
With the main switch, located on the ELT main unit, set at "ARM" position, the AK-
451 ELT is automatically activated upon sensing a change of velocity of 4.5 ± 0.5
Feet/Second, along its longitudinal axis (Automatic Fixed-ELT (AF) Configuration).
It is also designed to be removed from the aircraft and used as a personal locating
device when it is necessary to leave the scene of the accident (Automatic Portable
ELT (AP) Configuration) and survival ELT(s) configuration.
In the event of a crash, the AK-451 activates automatically, and transmits the standard
swept tone on 243/121.5 MHz lasting until battery power is gone. This 243/121.5
MHz signal is mainly used to pinpoint the beacon during search and rescue
operations.
For the first 24 hours of operations, a 406 MHz signal is transmitted at 50-second
intervals. This transmission lasts 520 ms and contains identification data programmed
into the beacon and is received by COSPAS-SARSAT satellites. The aircraft
GPS/NAV latitude/longitude data position will also be transmitted (if GPS/NAV is
connected with the ELT). The transmitted data is referenced in a database (maintained
by the national authority responsible for ELT registration) and used to identify the
beacon and owner.
Accuracy:
Doppler positioning is employed using both 121.5 MHz and 406 MHz signals.
Position accuracy of the 121.5 MHz signal is within an area of approximately 15-20
km radius about the transmitter. Due to the better signal integrity of the 406 MHz, its
location accuracy is within about a 1-2 km radius. If the GPS/NAV position data is
transmitted, the accuracy of the AK-451 will narrow to 22 meters (typically).
2.3
TRANSMITTER FUNTIONAL TEST
The ELT should be tested every month.
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WARNING
Do not allow test duration to exceed 5 seconds. A false alarm may be generated.
Any time the ELT is activated, it is transmitting a 121.5 MHz and 243.0 MHz
distress signal. If the ELT operates for approximately 50 seconds, a “live” 406
MHz distress signal is transmitted and is considered valid by the Cospas-Sarsat
satellite system.
Any time that the ELT Main Switch is lifted and flipped from “OFF” to “ARM”,
a 406 MHz self test signal is transmitted (after 25 seconds), however it is
specially coded as a “self test” signal that is ignored by the COSPAS-SARSAT
satellites.
2.3.1 Main Switch ON/OFF/ARM Operation:
In normal operation, the Main Switch, located on the ELT main unit, must be in the
"ARM" position. In the event of a crash, an acceleration activated crash censor (G-
switch) turns the ELT 'on' automatically when the ELT experiences a change in
velocity (or deceleration) of 4.5 fps ± 0.5 fps. Activation is also accomplished by
means of the cockpit mounted remote control unit or the "ON" switch on the ELT
main unit. To reset the ELT press either "RESET" switch on the remote control panel
or on the main unit.
The ELT has an "OFF" position. This allows the beacon to be handled or shipped
without 'nuisance' activation. Care should be taken when transporting or shipping the
ELT not to move the switch or to allow packing material to become lodged such as to
toggle the switch.
Main switch, alternate positions:
•
"ON:" ELT transmits immediately. Both Green ON lights on the main unit and
remote switch unit flash and the buzzer sound, at rate of 1 second ON, 4 seconds
OFF.
•
"OFF:" The ELT is turned off.
• "ARM:" ELT self-test is confirmed after 24 seconds. If the self-test is passed,
the 2 Green ON lights and the buzzer sound must be extinguished. The ELT system is
then in the "ARM" mode.
2.3.2
Transmitter ID Programming and Self-Test:
Turn the main switch from the "OFF" position to the "ARM" position. The
Buzzer sound and the 2 Green ON lights shall illuminate for 4 seconds, then
extinguish. This is to allow coding programming during the next 20 seconds window
and self-test for 1 second thereafter.