For the week of December 10 - 16, 2003

Airport navigation system awaits review

TLS to reduce flight diversions

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By MATT FURBER
Express Staff Writer

Construction of a Transponder Landing System (TLS), a navigational tool designed to help pilots establish a safe landing approach in marginal weather, is nearly complete at Friedman Memorial Airport. But, as concrete cures, antennas get final weather stripping and the metal shack housing the computer hardware buzzes with the first test results, commercial application awaits final Federal Aviation Administration review.

Advanced Navigation and Positioning Corporation assistant site manager Richard Tuton applies weather stripping to wiring on a localizer antenna. The antenna transmits and receives data between aircraft and the transponder landing system being installed at Friedman Memorial Airport. Once approved, the system will provide pilots who request the extra information a precise landing pattern at the airport. Express photo by Matt Furber

Airport officials hope the technology will improve the reliability of the airport by cutting in half the "minimum decision height" or the altitude below which pilots can be cleared to make a visual landing.

FAA review of the system is site specific and exhaustive, said Friedman Airport Manager Rick Baird.

"We need to wait for type acceptance. I am being optimistic," he said, hoping the system will come on line in early 2004. "It has been an onerous, laborious process."

Improving reliability of the airport was not the main aim of installing the guidance technology designed for airports with difficult terrain, but it is a byproduct of an effort to remedy another problem, said Airport Manager, Rick Baird.

"In the mid-1990s we had a significant amount of scud running going on," he said.

Scud running is a pilot’s term for an FAA approved practice originally intended for pilots of small aircraft, Baird said. It is a low altitude, low angle approach that facilitates a visual landing below a restrictive cloud ceiling.

Baird said the practice violates the voluntary noise abatement program initiated to help reduce noise pollution from aircraft in the valley. Some pilots fly as low as 500 feet above the ground.

"You could not believe a high powered jet would be flying in such weather to get in here," Baird said. "As far as I am concerned it is unsafe."

The new system is designed to receive a transponder signal from approaching aircraft and transmit a recommended approach pattern to navigation instruments standard on most modern aircraft.

The ease of communication without requiring aircraft to install new technology is a big selling point, said Pete Kincaid, vice president of marketing for Advanced Navigation and Positioning Corporation (ANPC), the company that designs and builds the system.

The system is rated to permit a landing when cloud cover comes as low as 200 feet above the ground. At Friedman, the system would be rated for a higher elevation due to the mountains, but that level has not yet been determined. It will be different for private and commercial aircraft, said ANPC project manager Rick Vogel, who has supervised the installation.

If the cloud ceiling is too low the system stops giving guidance and pilots must abort an approach, he added.

Pilots flying the largest, most sophisticated commercial aircraft with the highest category of navigation tools on board can guide aircraft on automatic pilot through zero visibility "pea soup," Kincaid said. TLS doesn’t have the same level of sophistication, but it will dramatically reduce the number of flights diverted through Twin Falls when it comes on line.

 

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