Wind turbines have the potential to be a hazard to air navigation, according to two new letters AOPA issued recently. While AOPA recognizes the role wind turbines play in green power generation, it is concerned that their tall construction could lead to potential collisions with aircraft and impact the reliability of radar.

AOPA made the comments in opposition to a bill in the Washington State legislature and on a request for comments to a wind farm proposed in Nantucket Sound off the coast of Massachusetts.

According to Greg Pecoraro, AOPA vice president of airports and state advocacy, "It has become increasingly important for AOPA to educate lawmakers across the country about the effects of these systems on aviation. Particularly so when the wind farms are in close proximity to airports," he said. "Aside from the obstruction itself, they can also interfere with communication and navigation, and wind patterns for all aircraft, especially gliders."

Pecoraro made the comments in his letter on Washington H.B.1008, a piece of legislation that would regulate the installation and operation of wind turbines in the state.

"If the systems were to be installed near arrival or departure paths of these facilities, the safety of passengers and crew, as well as citizens below, would be severely compromised," Pecoraro said.

AOPA also is working on a high-profile wind farm issue off the other coast, in Nantucket Sound. This proposal caused political fireworks a few years ago when residents of the upscale islands opposed the clean energy source. Aesthetics aside, AOPA said there are serious aviation considerations as well.

Responding to the FAA's request for comments on the wind farm as a potential hazard to air navigation, AOPA said the proposed 130 wind turbines that cover a 35-square-mile area of the sound would cause a significant hazard to air navigation.

"The area of significant concern to AOPA is the high volume of low-altitude VFR flights between Barnstable Municipal, Martha's Vineyard, and Nantucket Memorial Airport," AOPA said.

The letter went on to say that the wind farm would impact radar coverage in the area, making it unlikely pilots would be able to receive flight following and other radar services over the water at lower altitudes.

The association will continue to monitor the wind turbine situation in Washington, Massachusetts, and around the country.