Filed under: Flight
Hypoxia, or insufficient oxygen supply to the body, is a stress factor associated with high altitude in aviation. It’s caused by low oxygen levels and decreases in partial pressure. Flight above 10,000 feet is dangerous and restricted without supplemental oxygen, and even the best oxygen and pressurization systems fail sometimes. Above 10,000 feet, an aviator’s “Time of Useful Consciousness” (TUC) begins; this means that you’re going to start having problems focusing, reacting, and making decisions. At 15,000 feet your TUC is around 30 minutes, at which point you’re more likely to be unconscious than not. At 22,000 feet it’s only 5–10 minutes, and by 28,000 feet it can be as fast as 3 minutes! Look out for these signs (what you can see in somebody else) and symptoms (what you can notice in your own body):
- Cyanosis (bluing of the fingertips or lips)
- Decreased reaction time
- Impaired judgment
- Unexplained happiness/euphoria
- Visual impairment
- Lightheaded or dizzy sensation
- Tingling in fingers and toes
If you notice any of these signs or symptoms, remember to find the emergency oxygen, use it, and land safely!
Neck pain in military pilots, particularly helicopter and fighter jet pilots, is a major concern. Conditions inherent in flying helicopters and jets put these pilots (and crew) at a greater risk for developing neck pain due to misaligned postures, the use of additional equipment on their helmets, and exposure to high G-forces. Effectiveness and readiness are compromised if a pilot is can’t fly because of pain. Pilots sometimes forego medical treatment for fear of being grounded or losing their flight status and, as a result, pain is left untreated.
Exercise programs specifically for strengthening the neck area can be helpful in preventing pain. “G-warmup” maneuvers can also be beneficial to prepare a fighter pilot for high G-forces. Military researchers are looking at improving and updating the ergonomics of aircraft seats and cockpits, as well as helmet fit. In the meantime, see your doctor if your neck pain doesn’t improve with rest and basic at-home treatments. And for more information, read HPRC’s InfoReveal.
Why has the F-22 Raptor been depriving its pilots of oxygen for the last 12 years? Air Force officials recently told a House subcommittee hearing (a complete video of the two-hour hearing is also available) that they don’t know what’s behind the dizziness, confusion, blackouts, memory loss, fatigue, and eventually chronic cough (“Raptor cough”) that pilots experience while flying the stealth jets. After more than a dozen incidents between 2000 and 2011—and one fatal crash—where pilots were being choked by the plane, the Air Force’s entire F-22 fleet was grounded in May 2011.
Investigations ruled out low blood sugar and dehydration as possible causes of the symptoms and eventually concluded that the problem was an overinflated pressure vest that restricted breathing.
In response, a team of NASA engineers and Navy divers developed a new-and-improved pressure suit and back-up oxygen systems and removed a faulty charcoal air filter. These measures seem to have alleviated the problems—a dozen F-22s recently were deployed to Japan without incident. Now restrictions are being lifted, although the jets and their pilots are being closely monitored. Pilots currently must operate under altitude ceilings so that they don’t need to use the flight vests, and they must also stay close to emergency landing sites. Experts and scientists continue to investigate the primary cause of these incidents as well as improve safety and back-up systems.