Washington (CNN) -- After several highly publicized incidents involving sleeping or fatigued pilots and air traffic controllers, the Federal Aviation Administration is putting new scrutiny on the problem, requiring all overweight pilots and controllers to undergo testing for sleep disorders.
The order, announced by the FAA's federal air surgeon, is massive in scope and could apply to about 125,000 of the nation's 600,000 commercial and private pilots, according to one estimate, and an unknown number of the nation's 14,500 controllers.
Under the new policy, all pilots and controllers will be screened during their routine medical examinations. Those with a body mass index (BMI) of 40 or greater and a neck circumference of 17 inches would have to be tested for obstructive sleep apnea. A BMI of 40 equates to a 5-foot, 11-inch man weighing 287 pounds, according to the National Institutes of Health.
Sleep apnea, which can cause fatigue, is "almost universal" in people who fit those criteria, Dr. Fred Tilton, the federal air surgeon, wrote in a statement announcing the new policy. Pilots diagnosed with sleep disorders must be treated before they receive a medical certification needed to fly.
After appropriately dealing with pilots with a BMI of 40 or greater, the FAA will look at people with lower BMIs "until we have identified and assured treatment for every airman" with sleep apnea, Tilton wrote.
The Air Line Pilots Association, the nation's largest association of commercial pilots, said it is reviewing the policy.
A group representing private pilots, meanwhile, asked the FAA to indefinitely suspend implementation of the policy, saying there is no evidence to support the screening of general aviation pilots.
"This policy seems to be based on one incident involving an airline flight," Aircraft Owners and Pilots Association Vice President Rob Hackman said in a prepared statement.
"Analysis of a decade of fatal general aviation accidents by the General Aviation Joint Steering Committee didn't identify obstructive sleep apnea as a contributing or causal factor in any of the accidents studied," he said.
In February 2008, two pilots on a Go! Airlines flight from Honolulu to Hilo, Hawaii, fell asleep, overshooting their destination by 26 miles. When they awoke, the pilots at first explained their diversion on a missed radio call, and even flew the next flight, agreeing they were feeling alert as a result of the incident.
But the pilots eventually acknowledged they had fallen asleep. The captain was subsequently diagnosed with severe obstructive sleep apnea.
Fatigue was also a factor in the February 2009 crash of Colgan Air Flight 3407, which crashed near Buffalo, New York. As a result of that crash, the FAA has mandated new rest requirements for commercial pilots. Those requirements take effect in January.
Air traffic controllers have also experienced a spate of incidents involving fatigue. In 2011, the FAA fired at least three controllers for sleeping on the job, in one case intentionally.
The National Air Traffic Controllers Association on Wednesday declined to comment on the new policy.
In a statement Wednesday, the FAA said the new policy addresses a National Transportation Safety Board recommendation and is "designed to help airmen and aviation safety by improving the diagnosis of unrecognized or untreated obstructive sleep apnea."