Friday, July 15, 2005

Will Hailey airport switch weather landing system?

TLS losing favor; 'simpler' system eyed

Express Staff Writer

After waiting 10 years, Friedman Memorial Airport officials seem to have lost interest in the $1 million Transponder Landing System (TLS) that was to have sharply reduced the number of flights diverted because of seasonal low visibility at the field.

The TLS has been installed at Friedman, but it has not been certified by the Federal Aviation Administration.

Now, some interest is shifting to a Localizer Directional Aid (LDA), described as having more universal application for more pilots, no special training and no special on-board aircraft equipment.

The FAA's Northwest Mountain Region flight procedures manager, Terry Parnell, made a special trip from Seattle to a recent Friedman Memorial Airport Authority meeting to discuss various navigation aids that Friedman could install.

He pointed out that the TLS operation requires a commercial sponsor to hire an operator on the ground to communicate with user aircraft and assign a transponder radio code for making an approach during inclement weather. Parnell confirmed he had heard reports that the FAA does not want control-tower personnel operating the system.

Such a principal sponsor presumably would be one of Friedman's two commercial carriers, SkyWest Airlines and Horizon Air. One question not discussed was whether a TLS sponsor would allow access by other pilots to the system at no charge.

As for the LDA, Parnell said virtually all aircraft—including small general airplanes—have a standard on-board instrument that could access an LDA system.

Technically, the LDA is what could be described as the inexpensive half of an expensive, electronically advanced ILS (Instrument Landing System) used at large airports. LDA provides signals for a vertical needle on an aircraft's instrument that a pilot keeps centered during a landing approach to stay aligned to the runway.

However, LDA does not provide altitude information during an approach. Pilots would continue to use their altimeters to track their descent to Friedman, Parnell explained.

An LDA installation, which Parnell said the FAA would fund and maintain, would allow pilots to descend to as low as 6,300 feet above sea level or 983 feet above Friedman's 5,317-foot altitude in poor visibility.

However, Airport Manager Rick Baird said he preferred approach minimums no lower than 1,000 feet.

Baird said his concern is "missed approaches" at Friedman—that is, if an aircraft breaks off its landing approach in poor weather and climbs out of the mountainous area around Friedman, does it have the power and maneuverability to either circle inside the terrain "box" or climb out.

Parnell said the LDA system could be installed by August 2006.

But he declined to recommend any system over another.

The Airport Authority is mulling over whether to abandon TLS and give the go-ahead to the FAA to install LDA.

The major impediment to an LDA system, however, might prove to be the ground hardware. As Parnell describes it, LDA is an array of ground antennae that broadcast over an area 2,000 feet long by about 400 feet wide.

Signals are bounced off the ground, Parnell said, to reach inbound aircraft. But the area south of Friedman—the Eccles farm property—would require an easement from the owner and an agreement that farm equipment would be moved during LDA operations to avoid interrupting transmissions.

During discussions of navigational aids, one of the airport board's most ardent critics, Ketchum real estate executive Dick Fenton, appealed for the authority to hear from the manufacturer of the TLS system, Advanced Navigation and Position Corporation, of Hood River, Ore.

Fenton said that ANPC had stuck with Friedman for 10 years trying to activate a TLS system and the board owed it to the company to hear its arguments.

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