Group Pushes GPS to Reduce Air Disasters

Power lines and wind farms can pose near-invisible hazards to approaching planes.

A Norwegian consortium is developing a system to use GPS data to reduce the number of airplanes and helicopters that crash after collisions with power lines, buildings and other easily avoidable obstacles.

The system would be cheap, portable, and easy to keep up-to-date, according to the Norwegian analyst firm that is helping to lead the coalition. The GPS system should also be more effective than flags, orange balls or other static visual signs that are often the only warning approaching pilots get before crashing into power lines made nearly invisible by dark, fog or almost anything else that reduces visibility, according to Norwegian research firm SINTEF.

In Norway, 10 percent of all aircraft accidents are caused by collisions with power lines, without even including cell-phone towers and other potential hazards, the company said in a statement announcing the coalition.

Collisions in Canada are such a problem that grass-roots organizations such as Responsible Electricity Transmission for Albertans are lobbying for national laws requiring that power lines be buried rather than raised above the ground.

Power lines are only the most common obstacle, however, according to SITNEF. The best option available now is the Obstacle Collision Avoidance System (OCAS) developed by U.S., Canadian and Norwegian companies, and approved for use in the U.S. by the FAA.

The system relies on radar mounted on masts raised near particularly dangerous obstacles such as power lines. When the radar picks up a plane flying too close to the obstacle, the OCAS tower automatically radios and sounds an audible warning.

The number of potential obstacles makes the system difficult to set up and control, however, according to SINTEF, which slowed implementation in both Norway and the United States.

The risk of collision – with power lines and other obstacles – is so great that the U.S. National Transportation Safety Board (NTSB) called in July for ways to mark and put warning lights on wind evaluation towers, often put up near power plants to monitor wind and weather at altitudes of less than 200 feet and send warnings automatically by radio when something hazardous is happening.

The Federal Aviation Administration (FAA) is responsible for marking and notifying pilots of potential obstacles near flight paths, but doesn’t track wind evaluation towers or any other structures that rise less than 200 feet from the ground – which includes power line towers, cell phone towers, buildings and other potential low-altitude obstacles.

The number of those potential obstacles and frequency with which cell towers or other structures go up makes it “infeasible” according to the agency.

As wind farms become more numerous, they provide yet another set of potential hazards, which are also exempt from requirements that they be visible enough for the pilots of low-flying aircraft to avoid them.

Financial difficulties forced the founders to sell OCAS, whose the future of which is now in question – without having solved much of the problem for which it was created.

Since 2009, Norwegian helicopter pilot Jan Ivar Sandnes has been working with local utility Nord-Trøndelag Elektrisitetsverk (NTE) on a GPS based system that would be simple enough for any pilot to use and inexpensive enough to put in every cockpit.

After four years of limited use and development, Sandnes and his company NobileSoft agreed to a joint development coalition that includes SINTEF, the utility NTE, Energy Norway and another power utility called Statnett.

The main advantage of the system is that it can be contained entirely in the cockpit, relying only on GPS signals from existing navigation satellites to match an aircraft’s location to that of potential hazards, according to Sandnes.

Making it work requires far more detailed information than is built into current maps and guides, or that is easily available from anyone but companies that own the obstacles – power companies that know exactly where their power lines and poles are, but may not have shared that information with air-safety agencies.

“This data, relating to geographical position, cables and their heights, are both inaccurate and available in a variety of formats,” according to SINTEF analyst Trond Bakken.

Getting updates from power companies takes a predictable amount of effort; getting it from cell-phone network companies, the owners of tall buildings, or companies putting up wind evaluation towers or other tall, often temporary, structures will take a lot of money and legwork.

Getting the air-safety agencies in other countries to accept the concept and help gather data would also help, though it would vastly expand the amount of data needed to make the system complete and usable in areas wider than just Norway, Sandnes said.

“There is great interest in this project from overseas, and now that we have research expertise and experience backing it up, it would be very interesting to establish a multinational consortium to promote the system in the global market,” he told Engineering & Technology magazine.


Image: Rauch