The Federal Aviation Administration approved an alternative runway approach on March 7 that moves planes landing at Jackson Hole Airport away from the Tetons, Jackson Lake and the Snake River.

By shifting southbound planes to the east on a curved, “Next Gen” path, the route will reduce the distance aircraft have to fly by 14 miles and flight times by about three minutes, airport Director Ray Bishop said. The voluntary approach, Bishop said, is the first instance of a U.S. commercial airport altering a standard descent solely for the purpose of redistributing airplane noise.

Planes will fly east of Jackson, Jenny Lake

“The lake is noise-sensitive — there’s lots of people,” Bishop said minutes before taking a test-run of the flight path. “Over by Mount Leidy, there’s nobody.”

Due to the nature of winds in Jackson Hole, 90 percent of planes land on a north-to-south path.

The conventional landing route, Bishop said, has been in place for more than 50 years. It takes aircraft from the Buffalo Valley on a westward trajectory until they hit the eastern shores of Jackson Lake. Traditionally, planes would pivot directly over the lake and head south for about 16 miles before they reached the airport runway.

On March 13, a week after the approach was FAA-certified, Bishop took one of the first flights using the new route.

The new path is identical to the old route up to the Dunoir transmitter, a high-frequency navigation aid that’s located at 7,720 feet on a bluff south of Buffalo Valley.

At Dunoir, instead of heading straight toward the lake, planes now take a curved, west-southwest-south descent. The route realigns with the old flight path just north of Moose, where pilots typically switch off autopilot.

The new approach is permitted by the FAA only because of advancements in GPS technology, Bishop said.

“This would have been impossible 10 years ago,” Bishop said while seated in a Pilatus C-12 turboprop plane. “You’ve got to be able to detect four satellites at the same time for it to work.”

The single-engine plane, piloted by Kim Harrower, was donated to the airport for the flight by the Spence Law Firm.

40 percent of air traffic can use new path

Because it’s dependent on new GPS technology, the majority of planes flying into Jackson Hole Airport currently are not certified to use the new approach.

“If they’re equipped, it’s a much shorter approach,” Bishop said. “Most of your high-end corporate jets have the equipment, but not all commercial airlines do. Some of the older planes — let’s say American 757s — they don’t have GPS yet.”

The airport director figures that about 40 percent of Jackson Hole air traffic will make use of the new approach immediately.

Gary Pollock, management assistant for Grand Teton National Park, believes the proportion of planes using the new descent path will increase over time. He praised the airport for taking the initiative to approve a new approach.

“Overall, we view it as a good thing, because it will reduce noise over places like Teton Park Road and the Jenny Lake and Leigh Lake areas,” Pollock said. “We just want to give all the credit in the world to the airport board and to Ray Bishop and the FAA for making this happen.”

The new flight path, Bishop said, likely won’t change overall air traffic at Jackson Hole Airport.

A 1993 agreement between the airport and Grand Teton park restricts air traffic noise to “6.55 decibels per day,” Bishop said.

The sound allotment is colloquially referred to as the “noise bucket.”

“The bottom line is that with the newer, quieter jet engines, we’re not even close to that threshold,” Bishop said. “Even though there may be more traffic than there was 20 years ago, we’re well below. Today we’d be at about three [decibels].”