SEARCH AND RESCUE (SAR) COMMUNICATION

During rescue operations, it is essential that you use standardized communication procedures. Voice, hand, and signal communications are important in aiding a rescue. The primary means of communication is the survival radio carried by the aircrewman or supplied with the survival equipment. Instructions for using the radio are embossed on the radio case, and all crewmen must be familiar with the radio operations.

Radios

Depending upon available stock levels, air commanders may direct a particular radio to be used. If no particular type of survival radio is

Figure 5-36.\Survivor entering the rescue net.

available, each life raft must have an AN/URT-33A beacon or AN/PRC-90 radio set. We will cover the AN/PRT-5, AN/URT-33A, and the AN/PRC-90 survival radios in this chapter.

In addition to the automatic direction finder (ADF) capability of SAR force aircraft, the United States government also uses satellites that monitor guard frequencies for emergency locator transmitter (ELT) broadcasts.

AN/PRT-5.\ The AN/PRT-5 radio transmits a tone-modulated signal in both high- and ultrahigh-frequency ranges. The set has an inflatable collar assembly that allows it to float at sea or sit upright on land. The radio can operate continuously for 72 hours at 25C (77F). No provisions for voice or code communications or for receiving signals from search aircraft are available with this transmitter. The AN/PRT-5 radio operates on 243.0 and 8364 MHz. The assembly instructions and the directions for use are included with each set.

AN/URT-33A.\ The AN/URT-33A beacon radio is a battery-operated radio that transmits a tone-modulated radio signal. The battery provides 72 hours of continuous operation. It must be pointed out that this beacon should not be used at the same time the AN/PRC-90 is being used, as the AN/URT-33 will interfere with the voice communication signal of the AN/PRC-90. When you are using the AN/URT-33, do not point the antenna directly toward the receiving aircraft because of the type of antenna employed; a conical area perpendicular to the antenna tip does not radiate a signal.

Do not attempt to use the telescoping antenna on the AN/URT-33A radio without first detaching the flexible antenna. Use of both antennae creates interference in the transmission patterns of both.

To turn the AN/URT-33A radio on, you must move the switch to a position where the word ON can be read. This may be confusing to the aircrewman, and the AN/URT-33A could be on when the aircrewman thinks it's OFF.

AN/PRC-90.\ The AN/PRC-90 radio set is a dual-channel personal emergency rescue transceiver, used principally for two-way-voice or modulated-continuous-wave (MCW) communication between a downed aircrew member and a rescue aircraft. Provisions are included for transmitting tone MCW and swept-frequency homing beacon signals to guide rescue efforts.

The AN/PRC-90 is battery powered and contains a flexible antenna, an interchangeable telescopic antenna, a function switch (knob and indicator), an MCW button for Morse code, a volume control dial, and an earphone.

When you are using the voice mode, the AN/PRC-90 is capable of transmitting up to 60 nautical miles (nmi) and up to 80 nmi on beacon or code. A rule of thumb is that this and other survival radios are limited to a line-of-sight

Figure 5-37.\Rescue hand signals.

transmitting capability. Because of this lineof-sight imposition, you should try to transmit from the highest point in the area. All survival radios should be held at least 14 inches above the surface for best results. Signal range increases proportionally with the altitude of the search aircraft provided the line of sight is not obstructed. Degradation can be expected when the radio set is operated in bad weather and inside areas of rugged terrain. The radiated ranges given are obtained when the half-wave antenna is used; the range is typically one-third less when the quarter-wave antenna is used.