By Andrew A. Rooney, Stars and Stripes Staff Writer
February 16, 1943

AN AIR TRAINING DEPOT, England, Feb. 15 — Twenty thousand feet and more above the green of the English countryside, up where the cold begins, American and British flight surgeons today are carrying on their own warfare against an enemy swifter and quieter — and every bit as deadly as the Luftwaffe itself.

That enemy is the "thin" air of high altitudes; the air whose chemical makeup is deficient in the vital oxygen which keeps men alive.

After you pass 10,000 feet — and that's just about tree-top level for today's aerial warfare — the oxygen content of the air you breathe begins to get lower. So you switch to bottles of oxygen, breathed through a mask.

But let anything happen to that artificial oxygen supply, once you're up where the cold begins and the horizon is the ends of the earth, and you die, or at best become unconscious and unable to handle your plane.

Fight to Conquer Air

Air is rare at that height; and lack of oxygen and the comparatively low pressure at which what air there is enters the lungs, does queer things to a man. Combating that problem is one of the major headaches of the Air Force Medical Corps.

Research at Randolph Field has brought improvements, but equipment such as pressure suits and pressure cabins are impracticable in fighting planes because of their vulnerability.

Here, USAAF flight surgeons are still trying to find out what happens to a man at great heights. They are sure of one thing: A pilot and his crew must be made aware of the dangers that exist for them at those altitudes. Some of them are hard to convince.

Changing from their main oxygen supply to their "walk-around" bottle of oxygen, they have discovered that they can take several breaths of air at any height with no apparent ill-effects. This confidence is dangerous.

The Provisional Medical Field Service School of the Eighth Air Force here in England are now using a mobile pressure chamber in which high altitude conditions can be simulated to convince combat crews that a lack of oxygen does impair their efficiency.

The chamber originally was used by the RAF. It is mounted on a vehicle that can go anywhere a one-ton army truck can go, and the plan is to take it to every U.S. station in England.

The decompression chamber itself was built from an old boiler. It seats three men on each side, is lined with paperboard, and is fully equipped with a communications system and of course oxygen equipment.

Operator Keeps Check

At one end there is a small port-like window through which the man operating the decompression controls can watch the guinea pigs and give them directions over the phone system.

When the crews go through the one-hour test in the chamber, they won't go as "high" or stay "up" as long as they have in actual flight, but for the first time they can concentrate their full attentions on the oxygen problem without having to worry about flying the plane or dodging FW 190s.

In a typical test in the chamber flight surgeon Lt. Richard J. Trockman, Evensville, Ind., might be at the controls.

He seats the six men inside and makes sure the door is firmly closed, sealing the chamber. Back at the port he looks in at the men and starts the decompression machine.

"You are going up at the rate of 5,000 feet per minute," he explains. "You won't notice anything for a while."

In a short time he speaks to the men again.

"OK. All but No. 3 man on the right, put on your oxygen masks and set your indicator at 12,000 feet. Regulations call for all fliers to use oxygen at 10,000 feet, and the indicator should read up to 5,000 feet above your actual altitude."

The No. 3 man is going to be the guinea pig for the experiment. Lt. Trockman instructs the others to watch the man without the oxygen supply, closely.

Pressure Affects Ears

As pressure in the chamber is decreased, the men's ears begin to cluck as the pressure inside the inner ear becomes adjusted to the lower pressure more slowly than the rapidly decreasing pressure outside. The mucus of a headcold will stop up the passages, hindering the process of equalization of pressure inside and out.

This greater pressure inside causes the eardrums to bulge and, in extreme cases, rupture. In other cases the mucus is forced down the Eustacian tube (connecting nose and middle ear), lodges there and causes infection.

If a flier is troubled with sinus infections his forehead may begin to pain as the pressure in the clogged sinus passages remains the same while the pressure outside decreases, causing an outward pressure in the passages.

Lt. Trockman continues: "Notice No. 3's nails. Blue underneath, aren't they ? He looks a little pale. He is beginning to suffer from anoxia, the name given to lack of oxygen in the system.

"He is beginning to feel a little numb, but supremely happy — or maybe he is getting irritated about something."

"Sounds like a cheap drunk," someone comments over the intercom.

"Exactly," the flight surgeon outside explains. "The symptoms of anoxia are often similar to those caused by too much alcohol."

"I think I look all right," says the No. 3 man confidently, beginning to feel light hearted and cocky.

"How much is four times 13?" L J. Trockman asks him.

"That's easy," the patient replies without a moment's hesitation, "Four times 13, is 74."

It is one of the first symptoms of anoxia. The victim begins to feel as though he could lick his weight in hand grenades.

He Needed Oxygen

One story is told of a pilot who lost his oxygen connection while flying in formation. He stuck with the formation for some time, but soon he began to wander all over the sky. He called other planes in the formation over the intercom and bawled their pilots out for crossing in front of him. Actually they were having all they could do to stay out of his way.

Even when he got back on the ground, that pilot couldn't believe that he hadn't been doing a superb job of formation flying. Lack of oxygen had affected vital nerve centers. His control was poor, his reactions slow, and his ability for self-criticism absolutely non-existent.

In the chamber, the man without the mask is asked to perform several little jobs. Lt. Trockman may ask him to shuffle a pack of cards, tie his shoe lace, or write his name several times. Invariably he stumbles through these things. In his own mind he thinks he is doing a grade A job. His name never looked better to him on paper, he likes the way he ties his shoe lace, and thinks he shuffles cards like a Culbertson.

The flight surgeons tell a story of one test pilot who climbed to a high altitude without oxygen and took notes of his observation while he was up there.

When the pilot came down he couldn't find his notes. He had a pocket full of papers with doodlings on them but he was sure that he had taken accurate and complete notes. Obviously what he thought had been beautiful notes while he suffered from anoxia, were useless scratches on paper.

Eyesight is Affected

In the test chamber Lt. Trockman has the "guinea pig" put on the oxygen mask before the danger point is reached.

"Note the almost immediate change in the color of No. 3. His complexion improves, things look brighter to him. One of the first things that is affected by the lack of oxygen is the eyesight."

The RAF regulation is oxygen from the ground up on night raids, because it is the parts of the eye that provide good night vision which are particularly affected.

A decompression chamber designed at Randolph Field is also in England and will be used along with experiments in the RAF chamber.

The other problems of high altitudes are the "bends," the affliction usually associated with deep-sea divers. The bends, or aero-embolisms, are caused by the nitrogen and other gas bubbles which come out of solution in the blood as pressure increases, just as the carbon dioxide comes out of solution in ginger ale when the pressure is released with a bottle opener.

This problem is mainly one for fighter plane pilots, not for the medium altitude bombers. It is not a serious problem until a man reaches 35,000 feet.

In both these problems the mobile pressure chamber will be a help from the point of scientific observation, and more important, it will thoroughly acquaint the men who fly at high altitudes with their own problems, and in that way help them to overcome them.