Technique: Toughest airports

Learn how to land with tailwinds and steal lift from ridges

January 1, 2013

 

“Just don’t get a main wheel in the gravel,” mountain training instructor Gary Kraft said. He directed me to perch his Cessna 172 on the very end of the 3,305-foot paved runway as I turned to line up with the centerline. He wasn’t happy with the direction of takeoff, but we couldn’t violate Glenwood Springs Municipal Airport (GWS) Manager Dick Weinberg’s “bending-tree” rule.

After an unscientific survey on the AOPA Forum titled “I Was Wondering” and repeated in AOPA ePilot, Glenwood Springs, Colorado—elevation 5,916 feet—was picked as the most challenging airport of those named. It had something else going for it—a close proximity to Aspen, Colorado, nominated by members as the second most challenging.

“GWS can be a real challenge with gusty afternoon winds. Aspen is a cakewalk in comparison,” said one survey responder. Summer heat results in high density altitudes, as is the case at Lake County Airport at Leadville, Colorado (9,934 feet) and Aspen-Pitkin County/Sardy Field, Colorado (7,837 feet).

“The rule of thumb here in summertime,” said Weinberg, “is if you have a four passenger airplane, it’s now a two-passenger airplane.

“When it’s really gusty and going crazy because of the terrain, you can have the windsocks at each end of the runway looking at each other,” Weinberg said. He has taught at least 100 students without incident. They learned to stay on the ground if winds are swirling, and to be especially vigilant after 11 a.m. from mid-April to mid-July, when winds pick up.

One way, unless the tree bends

If wind and weather permit, Glenwood Springs is a one-way runway, and it’s not due solely to noise abatement over the city when taking off from Runway 32. Maneuvering as you would in a normal traffic pattern for Runway 14 is impossible due to mountainous terrain on both sides.

That’s why standard procedure is to land on Runway 32 and take off on the other end—Runway 14—even with a tailwind. The upslope of Runway 32 helps aircraft slow down despite a tailwind, while the downslope of Runway 14 (less than a 1 percent grade) results in terrain falling away as the aircraft climbs—even with a tailwind. But how do you know when the tailwind on Runway 14 is too strong?

“We have trees here on the left side, right across from the FBO building,” Weinberg said. “I tell people if you see a tailwind and you don’t know whether to go or not [on Runway 14], you look at the tops of those trees, and if those trees are bent over on the top, don’t go that way. It’s not the tailwind on the ground; it’s what happens after you get 50 feet in the air. The tailwind doubles all of a sudden, like a windshear. So what happens? You dump down. Hang on!” Weinberg said. But if you mitigate the risks and follow proper procedures, he added, “It’s a wonderful airport.” When winds are difficult his students are taught to land at nearby Rifle, Colorado, and wait for better conditions. (That’s also what experienced pilots do when conditions are tough at Aspen.)

The tops of the trees were bending, so I took off uphill towards town into the wind, climbing as quickly as possible in Kraft’s 160-horsepower Cessna 172 to be kind to the neighbors. When departing Runway 14 at Glenwood, as I did, you have a choice of two canyons, one to the right and one to the left. “A right turn over the interstate is prohibitive as most light singles would have to circle to achieve enough altitude,” Weinberg said. “A left turn toward Rifle is fine, and although you’ll be between the canyon walls for a while, you can easily outclimb the terrain. In an emergency, you have the interstate under you.”

After reaching a safe altitude we moved close to a ridge with updrafts to aid the climb before turning 180 degrees and departing back across the airport. We were climbing at 500 to 800 feet per minute on a warm October day, having set the mixture to what Kraft called “Glenwood rich” prior to takeoff. He set mixture for maximum power, slightly rich of peak, during the engine run-up prior to takeoff. Based in Aspen, he even starts the engine with the mixture set at “Aspen rich” by pulling the mixture control out about an inch and a half.

Glenwood Springs is a game to be played by experienced pilots with the foresight to call Weinberg for tips prior to flying there. If at your current experience level you feel a 3,000-foot runway is a challenge, and can’t land on a specific spot on the runway, you aren’t ready for Glenwood Springs.

Back to Aspen

Leaving Glenwood Springs, we needed to climb more than 1,900 feet just to reach Aspen’s elevation. Since Kraft also wanted to give me a tour of the highest peaks, we turned away from the approach (with a tailwind) and headed west into the highest peaks. We needed 11,500 feet to clear a pass near Capitol Peak before proceeding past the famous Maroon Bells twin peaks, and emerged from a canyon above Aspen.

Kraft urged me to fly near the updraft ridges to help with the climb, and I went as near as a flatlander can prudently go. It had zero effect on the climb. Kraft took over, moving the aircraft to within 100 feet of the ridge while I took pictures. I had to keep the window closed because opening it would have hindered our climb.

I asked Kraft how I would find Aspen, once flying below the peaks and through the valleys near the 14,130-foot Capitol Peak, without a GPS. “Get out the sectional,” he said, but I mentioned the peaks all look alike on the map and out the window. Kraft agreed, saying, “If you are unfamiliar with the area, you don’t belong back here.” We were 13 miles west of Aspen.

Like Glenwood Springs Airport, Aspen has opposing, one-way operations and, therefore, aircraft must frequently land with tailwinds on Runway 15—which slopes upward with a two-percent grade. Takeoffs are on the opposite end (one which the tower controllers can’t see) of the 8,005-foot runway and are conducted on Runway 33. Charter operators have both company and federal rules about landing with a tailwind, and must abort if winds are too high. One jet pilot recalled a passenger shouting, “It’s right there!” as the pilot aborted due to high tailwinds. Other passenger-induced problems include a demand for departures on hot Aspen summer afternoons when engine performance is degraded.

Once you are in a position to land, you are well below the peaks of nearby mountains. One pilot said his Citation X is too fast to turn tightly enough among the mountains for a circle-to-land maneuver, even if it were permitted by company rules, which it isn’t. A NetJets pilot said the safety planning and risk mitigation for a half-dozen of Colorado’s mountain airports includes a call to the operations chief. The two simply discuss how they feel about the safety of the upcoming flight.

I had hoped to fly the localizer-DME approach, which begins at 13,400 feet and offers only circling minimums that are more than 2,000 feet above the airport. Kraft noted the climb alone would take considerable time. He takes his instrument students to the Denver area. Most jet charter companies do not circle to land, and accept a small tailwind if necessary. They also do not fly a missed approach, but instead, “extract” themselves from the area. We heard a Beechcraft Baron on frequency accepting a clearance to land with a 15-knot tailwind on Runway 15. Two minutes later, after thinking it over, the pilot requested to circle to Runway 33.

Controllers report noninstrument, piston-engine aircraft popping out of valleys along the final approach route, announcing they, too, are inbound to Aspen—unaware that they have entered a busy flow of jets on instrument approaches.

On both of my flights, we emerged above Aspen from the “scenic” route through the western mountains that Kraft gives his mountain flying students and had to hold over a golf course off the end of Runway 33 until opposing traffic had landed. Since a 172 can easily maneuver in the tight space above the city, we were able to use Runway 33 and had the luxury of a headwind. Most of the time, opposing operations are the rule; take off on Runway 33, land on Runway 15. The only real issue for me when landing on Runway 33 was flying a squared-off right base leg aiming directly at the steep slopes of Buttermilk ski resort that formed a wall ahead. I tended to veer away from the mountain until Kraft pointed out I would be too high unless I flew to the extended centerline of Runway 33 before turning toward my final approach.

The only difference I noticed during my flights was the many seconds it took during the takeoff run before I could say, “Airspeed [indicator] alive.” With a little training, mountain flying can be enjoyable and scenically rewarding. You might even see one of the mountain goat herds that live above Aspen.

Email alton.marsh@aopa.org.

Here’s why I picked Glenwood Springs

The search for challenging airports began with a posting on AOPA’s “I Was Wondering” forum, followed by a request in AOPA ePilot. Three hundred of you responded.

AOPA members offered nominations in 35 states as the “most challenging airport.” Forty of those airports have one-way approaches, 30 are mountainous, 33 have steep slopes, 25 are in the bottom of a canyon—with another 32 in the bottom of a valley. Many have whipping crosswinds or turbulence, but I was looking for an airport that is a challenge even on a calm day.

A trend emerged; many had blind approaches where the runway is not seen until the last second or had threatening terrain on all sides. Over and over, many listed Telluride, Aspen, and Glenwood Springs, Colorado, airports. It seemed unfair to pick on Telluride since officials leveled the runway a few years ago. Aspen is well documented as challenging, but Glenwood Springs has the more interesting approach. Aspen flight instructor Gary Kraft agreed, saying, “Glenwood is the most challenging in Colorado, particularly when the winds on the ground or aloft are active.” That cinched it. —AKM

Happy Camp

Happy Camp, California, nearly won this competition for the most challenging airport in America. It is nestled in a 1,200-foot-elevation valley surrounded by 6,000 to 7,000-foot (msl) peaks and ridges. There’s barely enough room to fly a pattern, and if you do, the runway is at times obscured.

County Director of General Services Randy Akana, a pilot, said not too many fixed-wing pilots go to Happy Camp other than to hunt or fish. There is no fuel offered. “It can be intimidating,” he said. It is very low use except for helicopters operated by the U.S. Forest Service and medevac helicopters.

“It is built on the side of a mountain in a canyon,” said Airports Director Melissa Cummins, a student pilot. “When you turn downwind, the [side] window is pointed at the ground.” Since fixed-wing pilots are already avoiding the airport, it was disqualified. —AKM

Give up your Independence

Pilots using Independence Pass to navigate away from Aspen face a challenge a few minutes after departure. The canyon divides, and each has a road in the bottom. If you follow the wrong road, you’ll end up in a box canyon, unable to outclimb terrain, or turn around without hitting terrain. The highway across the pass reaches 12,095 feet above sea level and also is the Continental Divide. —AKM

It’s like an aircraft carrier

Six airports were listed by you as “aircraft carriers” because they perch on a mesa or mountain, with one—Ronald Reagan Washington National—cited for requiring a “carrier-like landing.” The airports termed “aircraft carriers” are: Yeager Airport in Charleston, West Virginia; Sedona Airport, Arizona; Los Alamos Airport, New Mexico; Ingalls Field in Hot Springs, Virginia; Mackinac Island Airport, Michigan; and Catalina Airport, Avalon, California. —AKM

Al Marsh

Alton K. Marsh | "AOPA Pilot" Senior Editor, AOPA

AOPA Pilot Senior Editor Alton Marsh has been a pilot since 1970 and has an airline transport pilot certificate and instrument and multiengine flight instructor certificates, aerobatic training, and a commercial seaplane certificate.