Army Aviation

MEDEVAC Search and Rescue Missions

Tech Talk / By Mr. Nathan Proper: A successful medical evacuation (MEDEVAC) search and rescue (SAR) mission must quickly and accurately locate/navigate to the person(s) in distress.

Soldiers standing by to load simulated casualties on a MEDEVAC Black Hawk / U.S. ARMY PHOTO

Therefore, having the latest life-saving and personnel locating technology on the aircraft is critical. Alongside the properly trained medics, the well-equipped MEDEVAC pilots and crew significantly increases the chance of survival for wounded soldiers, downed crews, and other persons in imminent danger.

One of the life-saving items of equipment used for these SAR missions is the Personal Locator System (PLS). Designed originally for the MEDEVAC H-60 helicopter equipped with the Forward-Looking Infrared (FLIR) system, the PLS relies on a receiver and antenna system installed on the aircraft to pick up transmitted signals from a person(s) in distress. The PLS provides navigation indicators to aid the pilots in locating anyone equipped with an AN/PRC-112 survival radio. These survival radios, when activated, send distress signals (also known as “homing”) over UHF frequencies. These signals are received by the PLS-equipped aircraft are processed into course and distance information the pilots can use to home in on the signal’s origin. This method of unencrypted communication has met with some vulnerability. Enemy opposition can intercept the homing signal burst transmitted by the AN/PRC-112, which can be used to identify the location of the person(s) in distress, and ultimately lead to a capture before recovery forces ever arrive.

Over the years, advancements in technology and obsolescence costs have had a negative impact on the PLS. In addition, Units have reported at after action reviews (AAR) that the PLS was rarely ever used and the required shark-fin antennas under the aircraft were prone to being damaged. Consequently, the PLS system was often removed for weight savings. In late 2015, the U.S. Army released an Aviation Maintain Action Message (AMAM), H-60-16-AMAM-03, to address the removal of the PLS. The AMAM states “The PLS is now considered obsolete. The PLS was a production line installation on HH-60L/M aircraft and added to select UH-60A/L aircraft by an Airworthiness Release (AWR). A recent general officer steering committee (GOSC) agreed to stop installation of the PLS on new production HH-60M, and approved local removal of the PLS from all fielded Units.”

Latest Technology
Soldiers are now equipped with Combat Survivor, Evader, Locator (CSEL) radios. The CSEL is a communication system equipped with precision Global Positioning System (GPS) geoposition and navigation data, two-way over-the-horizon (OTH) secure data communication, OTH beacon operation, line-of-sight (LOS) voice communication, and swept tone beacon capabilities. Position data can be securely transmitted from the soldier’s radio to a personnel recovery (PR) center or Joint Search and Rescue Center (JSRC).

Advanced technology, such as the Blue Force Tracking (BFT) system on the U.S. Army H-60 fleet, will accept the location data transmitted from a nearby PR or JSRC. The BFT system provides vast improvements in situational awareness. For example, this system will automatically display friend or foe locations which can be overlaid on the pilot’s moving map display on the Electronic Display Module (EDM) for H-60A/L, and on the Multi-Function Display (MFD) for the H-60M. Enroute MEDEVAC aircraft crew can also track specific locations such as casualty recovery areas and medical treatment facilities.

The PLS has served on U.S. Army H-60 helicopters for nearly two decades. In order to keep up with the changing battlefield environments, and to retain a tactical advantage over the enemy, Soldiers deserve the latest and most capable technology. The MEDEVAC mission plays an important part of these soldiers’ safety and survival. Although replacement systems are very costly to design, test, approve, and integrate onto the H-60 platforms, the PLS system may still not be fully compatible with existing CSEL radios. In addition to providing friendly (blue) locations and known enemy (red) locations, the BFT encrypted system also brings real-time situational awareness and secure networking capabilities for crews performing SAR missions.

Mr. Nathan Proper is a medical evacuation systems engineer in the Utility Helicopters Division of the Aviation Engineering Directorate of the U.S. Army Aviation and Missile Research, Development, and Engineering Center at Redstone Arsenal, AL.