NIOSH and the Mid-Air Collision Avoidance Working Group Prevent Aircraft Collisions in Alaska

A Story of Impact :

Aviation is a basic mode of transportation in Alaska. Alaska has six times as many pilots per capita and 16 times as many aircraft per capita when compared to the rest of the United States.¹ There are approximately 736 registered landing areas, in addition to the thousands of lakes and gravel bars where pilots land.³ Hazards can exist on the ground when aircraft are taking off or landing, and also in the air when sharing congested airspace.

During 2011 there were three mid-air collisions in Alaska. One of these collisions occurred in the Matanuska- Susitna (Mat Su) Valley between two seaplanes, fatally injuring four people. In response, the Mat Su Mid-Air Collision Avoidance Working Group was formed with representatives from industry, the military, the Federal Aviation Administration (FAA), Aircraft Owners and Pilots Association (AOPA), Alaska Airmen’s Association, the Alaskan Aviation Safety Foundation, the Alaska Air Carriers Association and the National Institute for Occupational Safety and Health (NIOSH). Mapping of Common Traffic Advisory Frequencies (CTAFs), which are the frequencies used by pilots to communicate while operating near an airport without a control tower, in the Mat Su Valley showed a substantial amount of overlap; pilots in an area could be on separate, but correct frequencies and therefore unable to communicate with each other. In addition, there were disparities between various sources of radio frequency information, including the FAA’s Alaska supplement, flight charts, and individual airport listings.

As a partner in the Mat Su Mid-Air Collision Avoidance Working Group, NIOSH analyzed data from FAA and Aviation Safety Reporting System databases and found very little overlap in reports of near misses and near mid-air collisions from Alaska. Alaska pilots were surveyed and locations of high traffic areas in the Mat Su Valley were identified. Radar data from air traffic control was reviewed to determine common traffic routes. Several scenarios were developed to clarify communication confusion; these scenarios were reviewed and evaluated by local pilots, commercial operators, flight instructors and airport operators.