Many METs fall just below the 200-foot Federal Aviation Administration (FAA)
threshold for obstruction markings. They can also be erected quickly and without
notice to the local aviation community, depending upon their location.
• Because of their size and color, pilots have reported difficulty seeing METs from the
air. Therefore, METs could interfere with low-flying aircraft operations, including those
involving helicopter emergency medical services, law enforcement, animal damage
control, fish and wildlife, agriculture, and aerial fire suppression.