Thermal plumes a potential danger near airport

August 5, 2010

Thermal plumes from a proposed power plant less than three miles from Byron Municipal Airport may pose a hazard to pilots, AOPA told the airport land use commission July 29.

The California Energy Commission is nearing the end of a 12-month review process before it decides whether to issue a license to the Mariposa Energy Project, a 200-megawatt natural-gas-fired facility with four exhaust stacks that would be located 2.6 miles southeast of Byron Municipal.

The Contra Costa County Airport Land Use Commission (ALUC) is also evaluating the project before determining whether or not it is compatible with the Airport Compatible Land Use Plan. The last of three public hearings on the proposal is slated for Aug. 11, and AOPA is encouraging pilots who are concerned about the potential impact of the plumes to attend.

As AOPA pointed out in its letter to the land use commission, the FAA recently added safety guidance  to the Aeronautical Information Manual (7-5-15) recommending pilots avoid flying in the vicinity of thermal plumes, such as those from smoke stacks and cooling towers. Noting that plumes can be invisible and that it is difficult to determine the extent of unstable air around them, the FAA urged pilots to keep their distance. Of particular concern to AOPA is the proximity of the plumes to the airport, potentially causing turbulence for landing and departing aircraft in the most critical phases of flight.

The FAA is also conducting additional studies on the potential hazards of thermal plumes, with results anticipated later this year.