WASHINGTON -- Federal aviation regulators have changed the way they track mistakes that bring planes too close together, a move that some safety experts say could hide risks of midair collisions.
Federal Aviation Administration officials say their new system will enhance safety and simplify a cumbersome process for classifying midair incidents.
Instead of using a complex formula, the FAA's new system ranks the severity of such incidents solely on how close planes get.
For example, jets at the same altitude must stay 5 nautical miles apart. Under the old system, an incident would be classified as high-risk if two planes breached the 5-mile limit, were flying directly at each other and a collision was avoided by the pilots taking evasive action, according to FAA regulations. Jets headed directly for each other could cover those 5 miles in about 20 seconds.
The identical circumstances would be classified as low-risk under the new system if the two jets got no closer than 4 miles. According to FAA data, the number of incidents considered high-risk will fall by more than half using this new formula.
Near-collisions are considered a key gauge of safety in the air-traffic system. There were 1,104 such errors last year, including 610 judged high-risk under the old formula.
In addition, the most minor incidents will no longer be counted as errors in FAA statistics, automatically decreasing error totals by about 25%.
"It's going to make them look like geniuses when really they've done nothing," says Bryan Zilonis, a regional vice president of the National Air Traffic Controllers Association union who helped draw up the old system. "You improve safety by reducing operational errors, not recategorizing them," Zilonis says.
The changes involve how the FAA tracks "operational errors," incidents in which controllers allow aircraft to come closer than rules allow.
Each error is classified for risk. Under the old system, many incidents categorized as high-risk were actually minor, says Tony Ferrante, director of the FAA's Air Traffic Safety Oversight Service.
The new system takes that into account, Ferrante says. It also is designed to improve capacity at congested airports by encouraging controllers to bring planes closer to the limits without fear of being cited for violations, he says.
Under the new system, controllers who breach the standard by 10% -- allowing planes to get 4.5 miles apart instead of 5 -- will not be considered in violation.
Several aviation experts voice concerns about the new system.
Former Transportation Department inspector general Ken Mead, whose office wrote several reports on midair incidents, says he fears that the FAA is, in effect, endorsing bringing planes closer together without conducting the complex safety analysis required to justify the change.
"Do you want planes coming that close together or not? If you don't, then you ought to say that," Mead says.
George Donohue, a former FAA official who now teaches at George Mason University in Virginia, says the multiple factors considered in the old system were necessary to understand how controllers made mistakes. "It seems to me that they are going in the wrong direction," he says.
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