At least two experts say that with the installation of satellite-based navigation equipment on SkyWest planes, reliability at Friedman Memorial Airport could be increased without making substantial improvements to the airport or adjoining facilities.
The Friedman Memorial Airport Authority heard an option for improving flight reliability at its meeting Tuesday.
Aviation consultants GE Aviation and Dave Mitchell from T-O Engineers, who relayed options from a meeting with Horizon Air last month, pushed for an improved RNP, or required navigation procedures, approach, which uses redundant GPS navigation. Flights to the airport currently rely on a standard GPS approach.
An improved RNP approach would shrink the required "buffer" of airspace around the craft. The procedure maps out paths for approaching the airport as well as what a pilot should do if he or she is unable to land.
That type of procedure can lower minimum approach heights—the height at which a pilot must be able to see the airport before landing. This minimum stands at 1,800 feet for a standard GPS approach, making it difficult for pilots to land at Friedman in cloudy weather.
Mitchell said Horizon Air is equipped to use this type of procedure, but the problem arises when Horizon Air policy is added to the mix.
Horizon policy allows this procedure only if, at the point that the pilot decides against landing, the plane could operate safely even if it were to simultaneously lose one engine and the primary navigation system, Mitchell said. He said it's questionable whether a plane, flying without the primary navigation system and relying on a single engine, could safely make the 85-mile missed-approach loop required by the current RNP at Friedman.
Matt Vacanti, an aviation specialist with GE Aviation, said the terrain involved to the north also makes it difficult for Horizon Air to execute a missed approach.
"The challenge Horizon has run into is being exposed to this terrain," he said. "The concern is that the terrain will cause fluctuations in [barometric] pressure."
Barometric pressure measurements help to guide the plane vertically and fluctuations would make it difficult for pilots to determine altitude, Vacanti said.
But Ken Shapero, spokesman and director of U.S. programs for a division of GE Aviation, said his firm has studied RNP approaches from the north that could bring minimum approaches down to 305 feet. Perry Solmonson, director of flight standards at Horizon Air, said that could increase the airline's reliability to nearly 99 percent.
"I'm not going to promise anyone here any specific minimum," said Ken Shapero, spokesman and director of U.S. programs for a division of GE Aviation. "[But] at the end of the day, with the tools that are available to us, we can find a solution that will improve reliability and access to this airport."
Two major issues may stand in the way of an improved RNP approach.
SkyWest told airport Manager Rick Baird during a November meeting that the airline has no interest in using an RNP approach, as SkyWest does not have the proper equipment and does not plan on acquiring it.
In addition, any new RNP approach would have to be approved by the Federal Aviation Administration and go through a process of public scoping required by the National Environmental Policy Act.
These requirements prompted concern from Airport Authority Commissioner Ron Fairfax, who said he's been through this process too many times to have faith in it.
"We've been through the FAA guy coming out here and saying there is no way [to improve approaches]," he said. "How confident are you that you can change the way the FAA paradigm is and get this approach through?"
Shapero said that though the process may take a year or two, he believes the FAA would eventually sign off on a GE-developed approach.
"There's reason for optimism here," he said. "I believe the FAA is ready to find a way to do this thing."
Baird said he and his staff would compile a report on increasing reliability at the current site and discuss the options with the FAA.
"If the FAA isn't solidly behind where you're going, you're wasting your time," he said.
Katherine Wutz: firstname.lastname@example.org