General Principles of Operation

The AN/PRC-63 radio set provides two-way voice communication with a searching aircraft that is equipped with compatible transmitting and receiving equipment within a range of 25 miles and an altitude of 10,000 feet. A search aircraft flying at 10,000 feet and equipped with compatible direction-finding equipment can locate an AN/PRC-63 radio set transmitting in the beacon mode at a distance of approximately 70 miles

Figure 5-7.-AN/PRC-63 radio set.

3. voice reception.

(line of sight) between the search aircraft and the radio set. The AN/PRC-63 radio set can be worn as part of the aircrewman's flight clothing or life jacket; it is secured to the garment by a strap attached to the slots in the battery housing. The automatic deployment device supplied with the radio set, when suitably connected to the parachute harness of the aircrewman by the user, will allow automatic transmission of the beacon tone upon parachute deployment. The radio can also be packed in a seat pack and, with the same deployment device suitably connected, can be automatically placed in beacon tone transmission mode upon ejection from the aircraft. The lanyard attached to the deployment device has been designed to withstand a pull force of 20 pounds without breaking.

The downed aircrewman may remove the radio set from his flight clothing, life jacket, or survival kit and change its mode of operation to either voice transmit or voice receive by pressing the appropriate end of the rocking toggle actuator. In the event that he becomes injured, disabled, or otherwise incapable of selecting the desired mode of operation, the radio set will continue to transmit MCW beacon signals until the battery power is exhausted.

Function and Use of Operating Controls

The function and use of the operating controls are described in table 5-1.

NOTE: When POWER ON/OFF actuator is in OFF position or in ON position with the deployment device installed, all other operating controls are disabled.

The radio set can be held in either hand and operated by the thumb or fingers, respectively. In the normal operating position, the speaker/ mike faces the operator.

NOTE: During operation, the radio set must be held in the upright position (antenna vertical), or loss of transmission or reception will result. For best results, hold the radio set approximately 1 to 2 inches from the mouth when speaking, or ear when listening.

In the receive mode the sound is controlled by the volume control knob, which is located in the upper corner of the radio set (opposite the flexible whip antenna) and marked VOLUME MAX. Full clockwise rotation gives maximum volume; full counterclockwise rotation gives minimum volume. The sound of the beacon monitoring tone is also controlled by this knob.

NOTE: Neither the beacon nor voicetransmitter output is affected by the position of the volume control knob.

Table 5-1.-Operating Controls and Functions

Inspections

There are three inspections/test intervals prescribed for this type of radio. (They are also prescribed for the AN/PRC-90.) The first daily/ preflight is performed at the squadron level by the aircrewrnan. It is to be performed daily or prior to each flight. It consists of a basic operational check using an AN/PRM-32 radio tester or with the aid of a known good radio. Prior to testing the emergency radio, you should call flight operations to inform them that you are going to test a radio.

Every 90 days the radio must be inspected by the PR at the organizational level. It is best to make this inspection in conjunction with the inspection performed on the aircrewmen's personal survival equipment.

The last of the three inspections is performed at the intermediate level (AIMD). This inspection is performed every 180 days by personnel in the avionics rating.

The testing procedures for all three inspections are outlined in NAVAIR 16-30PRC 90-2 for the AN/PRC-90 radio and in NAVAIR 16-30PRC 63-1 for the AN/PRC-63.

Battery Replacement

The Mallory battery will require frequent inspections to ensure that it hasn't lost any of its operating life. When operating in a hightemperature area, the inspection should be conducted at least every 30 days. The service and shelf life of the battery expires 36 months from the date of manufacture. When the battery fails to produce the power for the radio to operate at maximum operating range, you must replace it. Any battery that shows evidence of a swelling, chipped, or cracked surface, or moisture must be condemned and a new battery installed.