Murphy's Law: Fear Of The Friendly Skies


March 26, 2014: In the United States and Western Europe air safety bureaucrats are resisting calls to allow UAVs (Unmanned Aerial Vehicles) to be used for commercial purposes. In some European nations even military UAVs are heavily restricted from operating, even in air space controlled by the military. In other parts of the world UAVs are allowed to operate in civilian air space with no ill-effects. China has become an enthusiastic user of UAVs for monitoring pollution, crops and to do many other commercial jobs that previously were handled, at much high cost, by manned aircraft or space satellites. Israel does all that as well as flying UAVs through civilian air space just to get them where needed for some security or military situation. Israel is a small country and there’s not much choice. But the Israelis and Chinese also did the math and realized that UAVs are the real or even potential danger that American and European flight safety bureaucrats believe exists. That sort of thing does little to change the rules for UAVs in North America and Europe.

Flying has long been much safer than most people believed it to be. That paranoia has been extended to UAVs despite no lives lost to UAV collisions in Iraq, Afghanistan, or anywhere else. There is a potential danger with large (over 50 kg/110 pound) UAVs, as these are hefty enough to bring down manned aircraft. Yet in a decade of heavy use in Iraq and Afghanistan there has been one such collision for every 250,000 UAV flight hours. In the one incident so far there was no loss of life.

Despite the excellent safety record for UAVs in a combat zone, the fear of collisions has led to heavy restrictions on UAV use in disaster relief operations, which the military is often called upon for overseas and inside the United States. Right now the military must receive permission from the Secretary of Defense before using UAVs off the battlefield. That’s not really an issue at the moment because most recent disasters the military got involved in there were sufficient manned aircraft to look for survivors, assess damage, and so on. But overseas that is often not the case. Moreover disaster relief experts point out that in the early hours and days after a major disaster you can’t have too many eyes in the sky.

The one actual UAV collision took place in 2011 when a U.S. Army RQ-7 UAV and a U.S. Air Force C-130 transport collided. The RQ-7 hit a wing of the C-130, between the two engines. The RQ-7 was destroyed, while the C-130 had the skin of the front of that wing torn open and some of the interior spars bent. One of the props on the inboard propeller was destroyed (and that engine had to be turned off). But the C-130 was able to land safely, and parts and technicians were flown in to repair the C-130 where it was.

An RQ-7B Shadow 200 weighs only 159 kg (350 pounds), compared to 70,000 kg for a loaded C-130, so the outcome of this collision is not surprising. Shadow is small, being 3.5 meters (11 feet) long with a wingspan of 4.1 meters (12.75 feet). Most UAVs in the air over combat zones are even smaller. Indeed over 90 percent of them are the tiny two kilogram (4.4 pounds) Raven. Witnesses in Iraq and Afghanistan have seen a few of them destroyed, or simply knocked out of the air by a passing aircraft, usually a helicopter. Raven operators suspect that many of those that were lost for unknown reasons were similarly hit or caught in the backwash of low flying aircraft. A few have been seen getting attacked by birds. There have been very few recorded collisions.

The small, plastic, Raven would not do much noticeable damage to an aircraft. The pilots and crew of helicopters hit by Ravens apparently don’t notice it at all. After landing ground crews may notice a new dent and wonder where it came from. The Shadow collision was understandable because the Shadow is the largest UAV that often operates at low altitude (under 300 meters) and uses military airfields to land and take off.

In light of all this, the army is developing a new radar system (GBSAA or Ground-Based Sense And Avoid) to increase safety for UAVs. GBSAA is mainly a software system using existing radars to track UAVs and manned aircraft and alert UAV operators when their UAVs are too close to other aircraft (manned or unmanned). GBSAA can be expanded to use transponders (which commercial aircraft have been using for a long time) and more flexible software. But the basic idea is to insure that UAV operators are no longer “blind” to what is in the air nearby. GBSAA had its first field test a year ago and it was a success. The first GBSAA is to be deployed in 2014.

GBSAA will likely be more in demand by potential civilian UAV users. Battlefields have much lower safety standards than civilian air space, what with all those artillery and mortar shells, plus the bullets and rockets. But civilian air space has a lot of small aircraft and helicopters, so UAVs are generally banned. GBSAA could change that and make battlefields safer as the UAV traffic becomes denser.






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