Flying at fast speeds can cause a multitude of specific health complaints. Mikko Kaupinnen speaks to Juha Salminen, a pilot in the Finnish air force, about the health risks of being a fighter pilot

Flying at fast speeds in confined spaces is something that Captain Juha Salminen, an F-18 Hornet pilot with the Finnish air force, knows all about. After spending more than 600 hours in a fighter plane since November 2000, he has noticed changes in his health and has heard similar stories from other pilots, although they are all in good shape.

Popping capillaries

According to Salminen, the strong g forces that occur when executing tight turns, take their toll on the back, neck, eyes, and capillaries and are just one of the factors that affect the health of a pilot. Superficial capillaries rupture because of the increase in pressure in the veins during a tight turn, producing small (2 mm) telangiectases on the skin, especially on the limbs. The neck and back, however, usually bear the brunt of the high g forces. Many pilots have prolapse of an intervertebral disc. "A prolapse can occur in the beginning of a career of a pilot, in some cases as early as in the cadet phase," says Salminen.

US NAVY PHOTOGRAPHERS MATE AIRMAN MARK J RIBILAS

A prolapse results in numbness, weakness and pain of the limbs, as well as pain in the neck or back. Rest and sick leave are usually enough for recovery, but some pilots have to have surgical treatment. Even if a pilot avoids a prolapsed intervertebral disc, his vertebral column is still at great risk of damage--arthrosis of the cervical vertebrae affects the more experienced pilots. "The weight of the head with a helmet on can rise momentarily to an amazing 100 kg in an extremely tight turn and at the same time a pilot may have to turn his head," Salminen explains.

But the greatest risk to a pilot's back comes during the dreaded ejection seat jump. "In the event of an ejection seat jump, fracture of the vertebrae used to be more of a rule than an exception, although there has been substantial improvement made," Salminen says.

It goes without saying that excellent vision is absolutely vital for a fighter pilot and yet this is also jeopardised by high g forces. During a tight turn, the cranial blood pressure is lowered. After lowered blood pressure comes a "grey out," in which the pilot temporarily loses colour vision--everything looks grey. If cranial blood pressure continues to fall, narrowing of the field of vision may occur, and at the end of this phase, a pilot may only be able to use the cells of his or her macula. The next phase, black out, is a condition in which a pilot cannot see anything. The world looks black, even though the pilot is still conscious. "The final phase is a state called g lock, a loss of memory and consciousness. It is usually fatal," Salminen says. To help the pilot stay conscious, a g suit can be worn. This consists of a vest and trousers, and when g forces rise, pressurised air is pumped around the suit to prevent blood from pooling in the peripheries, maintaining the circulation to the brain.

Although pressurised air is needed to maintain blood flow to the brain, it is also essential for respiration. A pressurised air breathing system on a fighter plane ensures an adequate oxygen distribution for the pilot when flying high. This can also be damaging, however. Because of the pressurised oxygen pilots have to breathe, excessive pressure may be exerted on the maxillary sinuses and ears. Pilots notice this excess pressure the next morning as pain or a crackling sound in their ears.

US NAVY PHOTOGRAPHERS MATE 2nd CLASS JAYNE PASTORIC

"Take my breath away":without proper equipment the pilot will lack oxygen

Graveyard spiral

Other senses may be impeded during the flight too--this includes positional sense, which results in "graveyard spiral" during poor visiblity. During the graveyard spiral, the pilot thinks the aeroplane is rolling even though it is flying steadily. "The plane may start to roll when flying in thick clouds, but the pilot doesn't necessarily perceive it because of the zero visibility. If the rolling motion suddenly stops, the pilot may think that the plane has gone into a roll. In this situation the pilot just has to trust in the gauges of the jet, which indicate that the plane is actually flying steady. Otherwise a disaster may occur," Salminen explains.

But despite the dangers and health risks, can flying actually benefit a pilot's health? Captain Salminen believes it can. "To be able to do the job properly, you have to be in good shape both physically and mentally--flying keeps the pilot in top condition. One combat training mission can easily be as physically demanding as running 10 km and in turn this strengthens the muscles, which is the best prophylaxis against back and neck disorders," he says. He also does not see his work as especially dangerous--at least as long as peace prevails. "Fighter pilots can retire at the age of 45," he adds.

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