Electronic Weapons: Dead On Arrival


March 2, 2014: The U.S. Air Force was embarrassed recently when it was revealed that the PLBs (personal locator beacons) in ejection seats and parachutes (not part of ejection seats) failed 45 percent of the time when actually used and 24 percent of the time when the air force went and spot checked the ones that were waiting to be installed. The beacon (the AN/URT-44) weighs 540 gr (19 ounces) is water and shock proof and the size of a smart phone. The air force paid $1,765 each for 17,000 of these back in 2009. Delivery was complete by 2010. As the extent of the failure rate became known the air force decided to replace all the AN/URT-44s with a new locator design from another manufacturer.

What really bothered a lot of aircrew, who depend on these beacons to be quickly found by rescuers after bailing out, is that many air force personnel who ski spend $300 on avalanche locators, which make it easier to find skiers buried in snow by an avalanche. These locators have proved very rugged and reliable and cost less than a fifth of what was paid for AN/URT-44s. 

Despite this fiasco, the air force does take emergency equipment seriously. Much effort goes into designing, building and maintaining ejection seats and CSEL (Combat Survivor Evader Locator) radios. These devices, along with locator beacons are all part of the U.S. military CSAR (Combat Search and Rescue) system. Special satellites communicate with two types of SCEL radios: the older AN-PRC-112 and newer AN-PRQ-7.  Recent satellite upgrades made the system work faster, which is especially important since time is often critical. The PLBs emit a signal that nearby aircraft or ground personnel can detect. The PLBs are a backup device that are especially useful if air crew are unconscious or dead.

Pilots and crew of aircraft that go down use CSEL radios to let rescue aircraft know where they are. This is especially critical if you go down in hostile territory. The AN/PRC-112G uses GPS and satellite phone technology to send a brief ("burst") transmission of the radios (and downed pilots) location via satellite. When the rescue chopper is close enough (within line-of-sight) the AN/PRC-112G provides encrypted (the enemy can't listen in) two way radio capability to get any essential information from the downed pilot before the pickup is made. The AN/PRC-112Gs batteries are good for 96 hours of use.

The AN/PRC-112 was developed in the 1980s based on experience during the Vietnam War. CSARs first appeared early in World War II, when the Germans invented a hand cranked rescue radio (with a range of 300 kilometers). One was captured by the British in 1941 and copied. The design was passed on to the U.S., who produced their own version of it. After World War II new designs appeared that were smaller, lighter, and more capable than the original 15 kg (33 pound) World War II models.

The handheld AN/PRC-112 is being replaced by the more compact and 10 percent heavier AN/PRQ-7. Weighing .9 kg (32 ounces), the AN/PRQ-7 incorporates GPS, a beacon that can be picked up by satellite or nearby aircraft, and a two way radio. The AN/PRQ-7 batteries also last longer (over 450 hours) and the entire unit is more rugged and reliable. Over 50,000 AN/PRQ-7s have been bought since it was introduced 15 years ago and each costs about $9,000 (including a $1,600 battery pack). .

While CSEL radios have gotten better over the last four decades, they have also been used less and less. American warplanes and helicopters have become more reliable and American domination of the air has grown, as has the defensive capabilities of these aircraft. But aircraft, usually helicopters, still go down because of component failures or enemy action and the CSELs still get used.

The most expensive bit of emergency equipment is the ejection seat. These cost between $200,000-300,000. Most ejection seats weigh about half a ton, and are complex bits of technology. Ejection seats became essential as military aircraft became so fast, that a pilot could not safely climb out of the cockpit and jump. With the higher speed there was the danger of hitting the tail. Also, escaping pilots were often injured or stunned, and unable to get out quickly enough.

The first ejection seat was developed in Germany where the seats were first installed in their He 219 night fighters, in 1943. These used compressed air to propel the seat out of the aircraft. A year later, rocket propelled seats were installed in the He-162 jet fighter. By the end of the war, all of Germany's jets were equipped with rocket propelled ejection seats. While the Swedish firm SAAB had also developed a rocket propelled ejection seat, it was British firm Martin-Baker that jumped in after World War II and created a design that quickly filled the needs of most Western air forces.

The U.S. Air Force long insisted on using only American made ejection systems, but the U.S. Navy stayed with Martin-Baker because the American ejection seat did not function as well at very low altitudes (where a lot of naval aviators have to eject during carrier operations). Martin-Baker supplies about two-thirds of the ejection seats for Western fighter aircraft. The other major supplier of ejection seats was the Soviet Union. Those manufacturers continue to produce good ejection seats for Russian aircraft. Over 10,000 aircrew have successfully used ejection seats since World War II.




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