Thanks to improvements in air traffic management, planes flew smoothly in and out of the Aspen Airport over Presidents’ Day weekend.

Sardy Field has not seen a return of the severe congestion and delays experienced during New Year’s two years ago, when 2,500 airline passengers were delayed. Airport officials are cautiously optimistic that the problems have been solved by a reservation system and other changes.

Saturday night the airport was packed but almost all commercial departures remained on schedule.

“We’ve been kicking butt,” said Aviation Director Peter Van Pelt. The traffic management system is 90 or 95 percent effective for keeping things on time, he said.

“At this point, the engine overhaul is done,” Van Pelt said. “We’re just tuning it up.”

Space limitation was the greatest problem during Presidents’ Day weekend, but careful management didn’t allow it to become a problem.

“Our ramp will only hold so many aircraft,” said Fred Mosher, who manages ramp operations for Aspen Base Operation, the airport’s private aviation service. “We were at that limit for brief periods of time Friday night, Saturday and again Monday.”

Saturday, pilots were allowed an hour of “turnaround time” to drop off passengers, refuel and go elsewhere, Mosher said. Such a short turnaround time is a rare occurrence in Aspen, he said.

But the volume of demand never led to significant delays, thanks to the traffic management system.

“I believe it is the FAA’s willingness to regulate the flow into Aspen,” Mosher said.

The Federal Aviation Administration now limits the number of aircraft landing in Aspen and spreads out the arrivals through the day.

“We seem to have cured the problem we had in 1999,” Mosher said. “When all is going well, we’re able to accommodate everyone who wants to get here on any particular day.” Though travelers can’t always arrive at the exact time they prefer, he added.

Compared with the dismal New Year’s week in 1999, recent holidays have been busier, but the airport has handled the traffic better.

In 1999, the airport more or less handled 256 arrivals and departures on Jan. 2, and 319 arrivals and departures Jan. 3. This year’s New Year’s weekend was busier, but delays were avoided. On Jan. 1, 2001, there were 276 arrivals and departures; Jan. 2 had 374 arrivals and departures.

“That’s huge for us,” said Barbara DuBrul, air traffic manager at the Aspen Airport tower. “We had some pretty good numbers again this weekend.”

Friday had 300 arrivals and departures, and Monday had 330. The four-day President’s Day weekend total was just under 1,000 arrivals and departures.

Monday saw the delay of three Air Wisconsin departures, but those delays weren’t from the volume of traffic. The runway was closed for 35 minutes after a Beechcraft airplane did a belly landing when its landing gear failed. No one was injured.

The slowdown resulting from the closure rippled for as long as two hours, but the traffic was back to normal after that time, DuBrul said.

DuBrul said two factors helped stop the delays. First, she said, there is better coordination between the airport tower and the FAA’s Air Route Traffic Control Center in Longmont. The second factor, she said, is the tower has been keeping in touch with Mosher and adjusting the flow of arrivals based on the number of planes on the ground.

Van Pelt said the work of consultants hired two years ago has helped with the improvement. Recommendations were put into effect by mid-1999.

To keep planes flowing in and out, a reservation system called Ski Country was instituted. It governs the airports at Aspen, Eagle and Rifle. Each pilot wanting to land in Aspen during peak times must call the FAA in Denver to reserve a landing time. Scheduled airline flights are automatically granted a spot.

The key to keeping air traffic moving is observing the airport’s optimum flow rate, between 12 and 16 arrivals and departures per hour. Up to 18, and even 20, can be handled in optimum weather, Van Pelt said.

“But we’ve learned never to push,” he added. “We don’t make reservations for 100 percent of our capacity.”

The airport experienced serious problems Jan. 2-3, 1999, when holiday crowds were trying to return home. The waiting list for permission to taxi for takeoff varied between 10 and 35 aircraft at any one time during the weekend.

Because of congestion caused by private aircraft, an estimated 2,500 customers on commercial flights experienced delays trying to fly in or out of the Aspen Airport that weekend. Commercial flights were kept waiting on the ground along with private, chartered and time-share aircraft.

Airport staff contracted with InterFlight Services of Bellevue, Wash., to identify the source of congestion problems, analyze the problems and make recommendations.

By mid-March, InterFlight representatives had suggested three things. The first was to transfer the decision as to the number of arrivals from the Federal Aviation Agency’s Longmont office to the tower at Aspen.

The second was a “time-based metering system,” a computer system that allows only a certain number of incoming planes to land per hour, according to the airport’s ability to handle them. The third recommendation was a reservation system for private planes that locks in the arrival and departure times for scheduled commercial flights. They also suggested offering landing times outside the peak demand hours between 10 a.m. and 2 p.m.