Flying in the mountains: Expect the unexpected | SierraSun.com

Flying in the mountains: Expect the unexpected

Christine StanleySierra Sun

Photo by Ari Steffen/Sierra SunA small plane takes off from Truckee Tahoe Airport. Alpine flying can be risky for pilots who don't know their aircrafts' capabilities and parameters.

For pilots, mountains can be lethal. They harbor wild weather, thin air, and an array of fierce variables that experts say should be acknowledged and heeded.And while the reason for last week’s Learjet crash near the Tahoe Truckee Airport is still undetermined, it is feasible that the day’s turbulent and stormy weather could have played a role. “Flying in the mountains is just as safe as flying anywhere else, as long as you understand the aircraft’s capabilities, and your capabilities, and fly within those parameters,” said Robert Todd, owner of Todd Aero, and veteran mountain pilot.But there is a list of dos and don’ts that must be considered before any pilot enters mountain air. High on that list is wind, which can change direction and speed without warning, and send aircraft tumbling from the sky. Turbulent winds moving over mountain tops can be likened to river water rushing over a rocks. As the air passes over ridges it swirls – often violently – in pockets just beyond the crests. Planes that get pulled into those pockets can find themselves in big trouble.”On a calm day, it’s no big deal. It’s like the Truckee River in late summer,” Todd said. “But winter winds will take you right down. Even 747s get slammed into the ground because of wind.”

And it’s no help that aircraft flying at altitude already have to factor in low air density.”The higher you go, the thinner the air is,” Todd said. “The (aircraft’s) engine has to have a certain amount of air, and if it doesn’t get that much air, then it doesn’t put out as much power.” Variables, such as the temperature and the weight of fuel and passengers, must also be factored in, otherwise pilots might find themselves struggling to clear mountain tops or maintain altitude. Ice is yet another factor.”Aircraft cannot have any visible frost on the wings or flight surfaces because it affects the aerodynamics of the airfoil,” said Dave Gotschall, general manager of the Truckee Tahoe Airport. “A clean wing produces X-amount of lift, whereas a dirty wing will not produce that lift.” Mountain flying is so complex that the Federal Aviation Administration and many airports offer training courses specific to high-altitude weather, though there are no requirements for pilots to be allowed to fly in mountainous areas. “You really cannot be inattentive when mountain flying,” Gotschall said. “You have to think; you have to plan; you have to expect the unexpected. The prudent pilot would do his homework.”

For additional information on mountain flying, visit http://www.faa.gov