Descending Through the ‘Valley of Life’

It takes a sharp, fast descent to clear the Andes and land at Quito airport. But there’s a problem: You can’t always see the mountains. Even in the bright sun this spring morning, tufts of clouds hide jagged peaks.

As Flight 693 comes in for landing, its safety will depend on three things: guidance from the ground, the plane’s electronics and Capt. Tomas Llamozas’ personal knowledge of the terrain.

The Boeing 727-200 of Venezuela’s Servivensa airline is one of dozens of aircraft making mountainous approaches to Latin American airports this morning.

New radar and radio aids have made landings less daunting than they used to be, but there is little room for error. Personal experience--and a large dose of caution--still play a big role in a safe landing. Both will be in evidence today.

The Servivensa flight, from Lima, Peru, is nearing its final approach to Quito. Over the Andes 30 miles from the airport, it is 16,000 feet above the valley floors. But a few miles off to one side is Mount Cotopaxi, soaring 11,000 feet, its crest covered by clouds.

Descending at 200 miles an hour, the 23-year-old jet will soon be gliding over and past a string of other mountaintops. It is cruising through what Llamozas calls the “Valley of Life”--the carefully mapped way through the mountains to Mariscal Sucre airport.

With 33 passengers, Llamozas takes the plane lower. Controllers on the ground monitor the 727 on radar, ordering three course changes as they guide it through its approach.

Casual talk ceases in the cockpit. Captain, first officer and flight engineer are intent on the controllers’ voices, the plane’s instruments and the symbol-laden navigation charts before them.

Llamozas, a 21-year veteran of commercial flying, won’t comply with any command until he has tested it against his own mental map of the terrain. When you’re bringing down an aircraft with mountains on both sides, following a wrong instruction from the ground can be fatal.

At 8,000 feet, clouds envelop the jet. Only the instruments tell the pilots the plane’s speed, direction and angle of descent. A few moments later, the 60-ton plane emerges from the clouds. The pilotslook out quickly to reorient themselves. Air traffic control and their own sense of geography were correct: The plane is right on course, safely off to the side of the black peak of another mountain.

Eleven miles from Quito and the plane makes another turn. The pilots put down the landing gear. Hearing the wheels go down, the passengers may guess the landing is a done deal.

It isn’t.

The Boeing has locked onto a radio signal that should guide it to the proper direction and angle for landing. But it is another few seconds before the crew, staring through the windshield, can pick out the airport themselves and be certain the plane is on course.

From the flight deck, the one-runway airport looks like an impossibly small target: a tiny patch of grass with a worm-sized strip of concrete, smack amid the houses and office buildings of Quito’s smoggy downtown. Low hills still stand between the plane and the runway. At the runway’s far end lies a deep gully, more houses and, finally, the 600-foot-high black slopes of Condacocha Mountain.

Four miles from the airport, Llamozas begins to land the plane on the basis of his own experience. Following the slope indicated by the radio signal would bring in the plane at a steeper angle than Llamozas likes; especially if the runway is wet, he says, the 10,236 feet of concrete could prove uncomfortably short for stopping the plane in Quito’s thin air. He lifts the plane’s angle of descent by about 1 degree.

The worm of concrete grows larger as the plane reaches “decision height”--the moment when Llamozas must decide to go ahead with the landing or abort it and try again. He decides to proceed.

Descending ever closer, nose slightly up, the 727 sweeps over the end of the runway. The back wheels touch down first, then the nose gear. Flight 693 has landed.