Voluntary guidelines set for marking meteorological towers

June 23, 2011

The FAA has released its guidelines for the voluntary marking of meteorological evaluation towers (METs) in an effort to make them more visible to pilots conducting agricultural and other low-level operations in their vicinity.

AOPA has supported the FAA’s proposal to set voluntary procedures for marking and lighting the towers that are used to gather weather data, are constructed in rural or remote areas, and stand less than 200 feet agl.

AOPA noted in formal comments submitted Jan. 21 that the proliferation of such towers posed a “significant hazard to many types of aeronautical operations. The towers are very difficult to see and in some conditions are virtually invisible.”

In a policy statement released June 24, the FAA urged parties constructing the towers to acknowledge the potential hazard METs pose to aviation.

“While this guidance is not mandatory, the FAA anticipates that in the interest of aviation safety, developers and landowners will consider this guidance for METs erected in the environments described in this document,” it said. “The FAA recommends voluntary marking of METs less than 200 feet agl in accordance with marking guidance contained in this document and Advisory Circular 70-7460-l, Obstruction Marking and Lighting.”

The FAA issued the recommendation to mark METs in accordance with published guidance while noting that historically the advisory circular’s guidelines were not applied to METs less than 200 feet agl.

“However, the FAA recognizes the need to address safety impacts to low-level flight operations due to the construction of METs in remote and rural areas, especially as agricultural spraying season approaches,” the policy said.

“This action will improve safety in the National Airspace System, particularly for agricultural pilots and other low-level flight operations,” said Tom Kramer, AOPA manager of air traffic services.

The FAA said it took action in response to the concerns expressed by parties from state governments to agricultural operators about the visibility of METs. The towers are used by wind energy companies to gather data on possible sites for wind turbines.

The structures, the FAA said, “are portable, erected in a matter of hours, installed with guyed wires and constructed from a galvanized material often making them difficult to see in certain atmospheric conditions.”

METs less than 200 feet agl are not subject to regulatory notice requirements and do not trigger FAA aeronautical studies.