Tethers, Airplanes , Safety and Terrorism
Tethered Balloons Exist Now
A Flying Electric Generator (FEG) is a tethered device, and tethers going up to high altitudes obviously pose a problem to aircraft. While it is not well known, balloons tethered at altitudes up to 15,000 feet exist now at fifteen sites along the southern borders of the United States carrying radar equipment to detect illegal flights from the south trying to smuggle drugs. These are part of the Tethered Aerostat Radar System, which also provides the North American Aerospace Defense Command with low-level surveillance coverage in the Florida Straits.
These tethered aerostats, are located within horizontally and vertically restricted airspaces that are shown on aeronautical charts used by pilots.
Some time ago the FAA indicated that our planned demonstration should be in an already restricted airspace, and placed us in contact with military liaison officers. These officers suggested potential restricted airspace demonstration sites which Sky WindPower has investigated, and at which interest in participating has been expressed.
Our calculations show that by reserving less than one four hundredth of U.S. air space, located at relatively remote locations not on airway routes, all its electrical energy needs could be met. Less than one four hundredth of U.S. airspace is a small fraction of the amount of airspace which civil aviation must currently avoid.
Many people who are not pilots have the idea that pilots may fly anywhere they want, except over the White House and a few other key locations. While understandably pilots might not like to see more restrictions on where they may fly, there is already so much authorized airspace use for various specific purposes that the FAA maintains a website updated daily for use by pilots showing airspace locations and altitudes as well as time periods in which airspace is restricted. Either the airspace must be avoided or the pilot must seek permission to enter it. For those interested, the site is:
Presumably the country's need to become energy independent and to reducing global warming will also receive consideration for airspace use once altitude wind energy capture technology is shown to be capable of providing direct solutions to these issues.
Safety on the ground is a primary design consideration. Our four or more rotor designs provide an advantage over the twin rotor design in that no tail empennage (that is, horizontal stabilizer) is required. However, inevitably, crashes will occur, just as airplane crashes do occur. Our FEGs are being designed to be just as reliable as commercial airliners, whose safety records are incredibly good. And FEGs will only be taking off or landing in uninhabited areas, not at airports teeming with people in and around them.
Unlike nuclear fission power plants, another non-global warming energy source, FEG arrays would not be very tempting terrorism targets, and do not pose radiation worries whether from accident or deliberate action.
If an aircraft does fly into a tether in restricted airspace, tethers could be severed, and passengers killed. With the safety measures being implemented, it is expected that the rotocraft could be bought down without harm to anyone, and probably not to the FEG either, even if a tether were severed.
In April of 2007 for the first time, after over thirty years of no accidents, a plane flew into an aerostat tether off Key West, Florida. Three people were killed in this light plane, illegally flown, by a private pilot at night into this restricted airspace without utilizing available warning electronics.
There is a risk in any undertaking, and civilization must balance the low risk of using this promising technology against its potentially great benefits.