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Salt Lake Tribune: Airport airspace filling up

A longer-than-usual excerpt of this story, so I've moved it below the cut.

Briefly, the article discusses the increasing traffic volumes moving through Salt Lake City International Airport and the unique challenges that traffic faces. The nearby mountains and restrictions on which parts of the Salt Lake valley may be overflown mean air traffic has a 6-mile-wide corridor in and out of the airport. Combined with occasional routing problems because of weather and delays at other airports, it's rapidly becoming apparent that the SLC system needs changing to keep up.

Traffic controllers: Close calls and a narrow flight corridor point to the need for a redesign of the airspace, they say

All is quiet as air traffic controllers at Salt Lake City International Airport's tower work what is known as the "evening bank" toward the end of a recent summer day. There's no idle chatter. No goofing off. Just the silence of concentration.

For good reason. During the next hour—from 6:30 to 7:30 p.m.—the tower controllers will handle 114 takeoffs and landings, almost two flights per minute. It's a high-wire, high-tech ballet, bathed in the darkness of the basement control room and the green hues of the radar screens.

Down in their cubbyhole, the shift of eight "approach" controllers—who handle all flights within a 60-mile radius of the airport—choreographs the arrivals and departures of commercial and regional jets, smaller commuter turbo-props and single-engine planes into a cohesive, nonstop parade. Outside, the results are easily seen and heard, from the regular rumble of takeoffs to an intricately spaced line of approaching aircraft, their landing lights visible for miles.

"It takes you right to the edge, but after you've been doing it awhile, you kind of look forward to it," says Drew Crampton, a 15-year air traffic controller. "I enjoy being pushed. It's like an athlete playing against a tough competitor; it only improves your skills. At the same time, there are not a lot of options. There's not a lot of margin for error."

No, there is not. Salt Lake City International's air traffic controllers work a relatively small and unique airspace compared with their counterparts at other major U.S. airports. The towering Wasatch Mountains to the east and Oquirrh Mountains to the west essentially preclude a wider distribution of aircraft when landing to the north and approaching the airport over the west side of the Salt Lake Valley."We don't have much fudge room. Right now we're putting 1,248 flights a day through this little airspace. . . . it gets very tricky."
Clark Desing, SLC tower manager
That airspace is further constricted by rules limiting arriving aircraft to a corridor between Interstate 215 and the Oquirrh ridgeline. It is through this 6-mile-wide box that controllers must maneuver incoming planes.

When the winds shift, the approach to the south, coming from over the Great Salt Lake, provides more room for controllers to move aircraft. But even with that, when one combines all of the geographic barriers, the limited airspace and the sheer number of flights—with more than 400,000 takeoffs and landings annually, Salt Lake City International is North America's 15th busiest commercial airport—the challenges for air traffic controllers are significant. This is particularly true during peak traffic periods, and especially in bad weather, when visibility is limited and aircraft are operating on instrument (not visual) flight rules.

"The complexity issue is extreme," says Clark Desing, the Federal Aviation Administration's tower manager at Salt Lake City International. "We don't have much fudge room. Right now we're putting 1,248 flights a day through this little airspace. And when you get a lot of arrivals and departures close together, it gets very tricky."

Close calls: And occasionally, stuff happens—as FAA records reveal.

On the afternoon of Aug. 11, 2002, a departing northbound SkyWest regional jet was looped west, under the stream of arriving aircraft at 11,000 feet. When the controller turned the plane again to begin another loop through the arrival stream and start its journey east, it suddenly found itself in the path of a smaller, southbound turbo-prop, also traveling at 11,000 feet. A second controller spotted the convergence and immediately ordered the SkyWest flight to dive to 10,000. The two planes missed each other by just 400 feet vertically and a half-mile laterally—just seconds, in other words; the two controllers handling the planes had failed to properly communicate with each other.

Then there was the evening of Feb. 4, 2003. During the airport's peak traffic period, with the weather deteriorating and the tower shifting from visual to instrument flight rules, a SkyWest regional jet made a swooping turn over South Jordan to line up for a final approach to the north at 8,000 feet. Suddenly, it found itself nose-to-nose with a southbound Delta jet—which had been trailing the SkyWest flight at the same altitude but drifted toward the final approach path because of high winds. With its collision alarm sounding, the SkyWest plane was ordered to quickly climb to 9,000 feet—but not before the planes got within 400 feet vertically and two miles laterally of each other.

Before the next 90 seconds passed, two other planes in that final approach flow would violate the FAA aircraft separation standard of 3 miles laterally and 1,000 feet vertically, as the controller fell behind the traffic curve and struggled to get things back on track. The convergence of close calls still sends shivers down the backs of local FAA officials.

"It took 10 years off my life," says tower manager Desing. "I'll never forget it."

Bold emphasis is mine; the Trib's online formatting leaves a hell of a lot to be desired.

I've been on a couple of flights out of SLC when the planes have taken sudden turns or dives/climbs. Never thought much about it, because in one case there was a storm over the Great Salt Lake and I figured we were getting turbulence from that, and in neither case could we see any other aircraft close to our own plane. We were also still in the initial climb, so everyone was still snug in their seats, obeying the seatbelt signs.

But now I wonder. There was a midair collision over Kearns some years ago—I remember the endless coverage it got at the time, as the newsies circled around residential neighborhoods in helicopters and on the ground while police and firefighters, and later NTSB and FAA officials, picked through trees and yards to make sure they collected all of the parts (both airplane and human) to ensure their investigation would be complete and to account for everyone and everything. Since then, every time I've been in the West Valley or Kearns areas and heard planes overhead, I've often kept one eye on the sky so I could dodge at the first sign of anything gone horribly awry.