Flying an airliner across the Atlantic is mostly a routine of mathematics and organization, but in spite of infinite forethought there are still times when the captain lives hours in the space of seconds, when each minute seems a day. The critical part of the drama that follows took only seven minutes, yet during every one of those 420 seconds, death was never more than a hairbreadth away.

It was a sweltering summer evening at Orly Field, Paris. In the cabin of the airliner 85 passengers fretted, eager to be off. Some were vacationers going home to the United States; some were emigrants, with suitcases and parcels; one was the captain's 18-year-old son, returning from a graduation trip to Europe.

The plane was scheduled nonstop to Idlewild, with 27 tons of fuel aboard; that brought the total weight, plane included, up to 80 tons, only a shade under the legal maximum. But that was no concern of the passengers, relaxed now and chatting gaily as the plane taxied out.

Up front it was a little different. The cockpit of an airliner is always full of strain before take-off. Tonight all seemed well; weather over the Atlantic was fine. Everything on the airplane had been checked and double-checked, but still the captain was concerned about two points on the take-off roll, called VI and V2.

VI is that speed, once passed, that commits the plane to take off. A few seconds before that, if there is any malfunction in the engines, the captain can cut the throttles, reverse the propellers, stand on the brakes and come to a stop before the end of the runway. After that, the plane will be going too fast to stop and, in case of trouble, the only safety lies in height. The hot, thin air of this August evening, the heavy load, meant using up a lot of runway before they would reach V2, the speed at which the airplane would rise.

At the edge of the runway they stopped and ran up each engine with minute care, studying the dials for the slightest sign of mal- function. Everything seemed perfect. Nevertheless, for five minutes they worked through the printed check list: "Compasses in sync ... prop feathering checked . . . hydraulic pressure up . . . mixtures full rich ... fire warnings tested." Each member of the crew answered in turn: "Ready, Captain!" To a layman, they would have seemed almost bored; to a professional, the tension could have been sliced. This crew knew, as all crews do, that despite every precaution there is always the element of chance- the statistical chance, for instance, that in one out of every 20,000 take-offs an engine will fail.

The captain faced forward. "Give me take-off power!" The plane shuddered and strained, held firmly on the brakes until the roaring engines built up to full power, long flames pouring from exhaust pipes glowing red-hot in the dusk. Then the captain lifted his feet. The run- way lights began to roll past, slowly at first, then in rapid flicks. The captain bent forward, left hand on the nose wheel steering column, right hand resting lightly on the throttles. Listening intently to the engines, he was ready to chop them at any instant. The first officer sang out the increasing speed.
"Ninety ... one hundred ... one five ... coming up on VI ... coming ... Vl!"

Quickly, the captain shifted his hands to the main controls, ready for flight.
"One thirty ... one forty ... one forty-five ... VII!"

The captain hauled back on the control yoke, the heavy plane lifted clear. "Up gear, up flaps! Meto ( maximum-except-take-off) power!" The landing gear locked into place.

The overheated engines relaxed a shade.

And then, without warning, disaster struck. On the instrument panel a red light flared. A bell clanged, so loudly that it drowned the engines. From the engineer came a message that filled all with dread. It was that one chance in 20,000.

"Captain, No. 4 is on fire!"

This was the critical moment at which a power failure could kill them all. Minutes later they would have been high enough to maintain height on three engines. But now the heavy plane was speeding at 150 mph., only feet above the ground. To the captain, the nightmares of a lifetime had come true. But in those nightmares, like all good captains, he had rehearsed the decisions he would make in every possible emergency. Now he summoned the repeated experience of simulated emergencies into action during the seconds available to him in crisis.
"Feather it!"

"It's feathered!"

"Fire first bottle!" Buried in the wings were steel bottles filled with fire extinguisher under high pressure. The engineer pressed a switch.

"Fired, Captain!" A cloud of chemical streamed into the burning engine.

Almost instantly the red light shut off, the bell stopped. The fire seemed to be out.

But a hideous obstacle now confronted them. Straight ahead lay a row of apartment houses. Though only half a dozen floors high, the roofs were above the airplane's nose. Normally, planes made a procedural turn before they reached them. Now, with one engine out, the captain dared not bank steeply, for such a turn would decrease the lift of the wings and send the airplane spinning groundward. There was only one salvation: climb.

The captain eased back on the controls. The air speed fell five knots, and a faint shudder ran along the plane. To the captain it signaled certain death from an impending stall. Instantly he put the nose down again. The plane would not climb.

One more weapon remained- resumption of take-off power on the remaining three engines. But take-off power imposes tremendous heat and strain, and the maximum use is two minutes. The captain had used that up. If he made a second call too soon, an engine might falter, and they would hit the apartment houses dead center. His mind, racing against the seconds, figured the smallest increase that might lift them over.

"Give me four inches more pressure. Quick!"

The relief pilot was crouching at his side. Together, they watched the onrushing roof. It seemed to sink a fraction. The crew scarcely breathed. Then the relief pilot did a courageous and dangerous thing. Although the captain's face was calm, he was streaming with sweat and his hands were rigid. The relief pilot knew that all depended on the sensitive fingers of the man at the controls. At the risk of fatally distracting him, he reached forward and touched his captain's arm.

"Take it easy. . . . I believe you have it made!"

The captain's hands relaxed a fraction and the airplane swept over the roofs, a bare few feet above them.

But now all Paris lay before them, a dense mass of houses, packed among narrow, twisting streets, their thousands of ancient chimneys smoking from the fires over which Parisians were cooking their suppers. In the cabin, the passengers gazed into open attic windows, praising the captain for giving them such a low-level view of the city; but to him the low altitude meant that at any moment he might encounter a building higher than the rest. Somehow he had to climb.

Again the captain eased back on the controls. Again, there was the deadly shaking. Only one sure means of survival was left: to dump fuel. His speeding mind weighed a terrible decision. Aboard the plane were 95 persons, including his son. To dump meant probable escape for them all; but 6000 gallons of high-octane gasoline, hosed down from zero altitude on the crowded old city, hitting the cooking fires and gas flames, could start a fire which would kill thousands.

His decision was automatic. He began inching the airplane's nose in a long, slow turn to the right, his fingers feeling each faint tremor from the laboring wings. The first officer, reading his mind, snatched up his mike.

"Le Bourget Tower, Le Bourget Tower! We have a fire emergency. We are attempting to overfly the field and dump on the far side."

If they could make Le Bourget, the other big Paris airport, there was open country beyond. Only the crops would be ruined by dumped gasoline. The nose crept around; Le Bourget came into view, swung under the wings. It was agonizing to watch salvation so close at hand, the smooth runways waiting to receive them, and not be able to land; but they were nearly 20 tons overweight with fuel (the safe weight for landing being considerably lower than that allowed for take-off). If they tried it, the landing gear might buckle and the whole of Paris would be lighted by their funeral pyre.

As the field moved astern, the black countryside loomed ahead. "Stand by to dump!" Back in the cabin the passengers had been told of the emergency and the stewardesses were moving rapidly up the aisle, cautioning against any violation of the "No Smoking" sign, checking each seat belt. There was no panic.

Up forward the engineer closed his fingers on the dumping switch, and slowly the laboring plane began to rise. To the captain, no experience in life compared with the exquisite sensation of feeling the plane lighten under his hands. No image in his memory compared with the sight of the altimeter needle as it began to creep around its dial. The situation was still critical, for the fuel tanks were still heavy and the engines overstrained. But the awful, hopeless seconds were over.

"Advise Orly Tower have completed partial dumping, am returning to field."

The French controller, fighting to keep his accented English clear and concise, answered them. Everything was cleared. Fire trucks were already tearing out to the runway, followed by ambulances and medical teams. In the cabin, the purser broke the seal on the escape chute that could bridge the 12-foot gap between the door and the ground if it became necessary to evacuate before steps could be brought.

Now remained the tricky business of landing on three engines. Carefully, listening to the engine pulses, the captain swung the big plane into the path that led to the runway.

"Turning on final. Flaps 20 degrees. Gear down I"

The captain breathed a silent prayer that the gear would not buckle on impact. Exhausted as he was, he needed to put the airplane down as softly as a master pilot could do it. He eased it over the fence, the first officer calling each five-mile reduction in speed. Out of the corners of their eyes, they sensed the fire trucks tearing along, striving to catch up. Softly, softly ... then came the thunder of the wheels, the smooth contact with the blessed runway, the solid feel of the concrete, the lovely concrete.

They rolled up the runway, turned off, stopped. For a moment the captain leaned heavily on his forearms, his head bowed over the control yoke. Then he turned to his crew. They stood staring at him, rigid, pale as death in the dim light. Then, spontaneously, they all smiled. In their exacting profession, this was a moment of perfection and pride. The years of experience had paid off.

Before midnight the engine had been replaced, the plane refueled, a routine take-off accomplished. Fifteen hours later they landed uneventfully in New York.