Low-flying C-17s and general aviation aircraft aren't a good mix. That's what AOPA is telling the U.S. Air Force about its proposal for C-17 flight training in the Susitna Valley north of Anchorage, Alaska.
The Air Force is planning on converting the fleet of turboprop C-130 Hercules aircraft based at Elmendorf Air Force Base to the larger and faster C-17 Globemaster. The military is completing a draft environmental impact statement on its plan to use the C-17 in existing Alaska military flight training areas, which would include low-level, slow-speed routes (SRs) in the Susitna Valley. Unlike military training routes (MTRs), SRs are not shown on civilian aeronautical charts.
"A mix of slower, light general aviation aircraft with faster, heavier C-17s in military training areas...constitutes a hazard to general aviation aircraft," AOPA said in comments on the draft environmental impact statement. "The increased weight of the C-17 over the C-130 will result in an increased risk of wake turbulence." The Susitna Valley is a VFR corridor between Anchorage and Talkeetna. "AOPA contends that the Air Force needs to fully analyze the flight safety risks associated with mixing C-17s with small general aviation aircraft," the association said.
AOPA offered several mitigating steps the military could take, including publishing the SRs so that civilian pilots would know where to find them, providing a common traffic advisory frequency and requiring C-17 pilots to communicate with GA pilots when using the routes, and providing a schedule of all military training flights to the flight service stations serving the area.
March 10, 2005