Air Force scientists battle aviator fatigue
By Tech. Sgt. J.C. Woodring, Air Force Print News
/ Published April 30, 2004
BROOKS CITY-BASE, Texas -- Air Force scientists here are using their research to help battle fatigue in aviators.
“Fatigue from sustained operations can place pilots at severe risk from (decreased alertness) unless effective fatigue-management strategies are (used)” said Dr. John Caldwell, a scientist with the Air Force Research Laboratory’s fatigue countermeasures branch here.
One strategy involves using medications to enhance alertness. For more than 60 years, dextroamphetamine was the Air Force’s “go pill” of choice. In December, a new compound, modafinil, was approved for some bomber missions, he said.
The scientists studied the effectiveness of modafinil on pilots of single-seat fighters.
Before testing modafinil, researchers studied fatigue in F-117A Nighthawk pilots at Holloman Air Force Base, N.M. They looked at the effects of being awake for 37 hours on alertness and flight performance.
Laboratory and simulator tests were repeated every five hours to help track the pilots’ level of fatigue, officials said.
Researchers looked at the aviators’ ability to monitor flight gauges and calculate basic mathematical equations. They also monitored eye movements and changes in pupil size.
While no one crashed or even came close to crashing, researchers said flight precision most noticeably changed between 9 a.m. and 2 p.m. of the second day of the test.
“This surprised us because we thought it would happen much earlier in the day,” said 2nd. Lt. Jennifer Smith, a behavioral science specialist at the laboratory who worked on the study.
Armed with this data, the scientists returned to Holloman a few months later for the modafinil study.
Once again they repeated the same tests as before; but this time, the pilots were given modafinil.
Scientists said that while the pilots were on the medication, their performance “significantly improved,” especially after 25 hours without sleep. The pilots also sustained brain activity at almost normal levels despite their sleeplessness.
During the simulator tests, modafinil “significantly” reduced the effects of fatigue during flight maneuvers, researchers said.
Under the influence of modafinil, flight performance degraded by 15 to 30 percent. Performance by pilots without the medication degraded by 60 to 100 percent below rested levels.
Researchers concluded that the medication was effective for reducing the impact of fatigue; however, aircrew members did not entirely maintain performance at fully rested levels.
Until more research is done, scientists said modafinil should be viewed as an option to, but not as a replacement for, dextroamphetamine. A 100-milligram dose of modafinil was apparently less effective as three 10-milligram doses of dextroamphetamine.
“Pilots who choose to use modafinil should be warned that [its] effects often are not readily noticeable despite the fact that the drug is working effectively,” Dr. Caldwell said. “Therefore, they should not prematurely discontinue modafinil without consulting with a flight surgeon.”