The Federal Aviation Administration is warning pilots to stay at least five miles behind Boeing 757 jets because of turbulence that may have caused a jet crash last week that killed five people.
FAA administrator David Hinson said in a letter to the nation's 700,000 general and commercial pilots that the agency is studying the wake turbulence characteristics of the Boeing 757 after several incidents involving jets following the narrow-body jet, an agency spokesman said Friday.The most recent incident was a crash on Dec. 15 that killed all five passengers aboard an Israeli-built Westwind corporate jet approaching John Wayne Airport in Santa Ana, Calif.
Other incidents included a Cessna Citation crash in Billings, Mont., that killed eight people last year and a Boeing 737 that did an uncommanded roll near Denver, FAA officials said.
"It is possible that one or more of (the incidents) may have been caused in part by an encounter with wake turbulence from a preceding B-757," Hinson said in the letter.
The letter warned pilots of both small and large aircraft operating under visual flight rules to stay at least five miles behind a Boeing 757 at the same altitude or less than 1,200 feet above to avoid air turbulence problems.
Previously the five-mile rule had applied only to planes flying behind heavier aircraft such as the Boeing 747.
Hinson noted that the crashes and other incidents are being studied by the National Transportation Safety Board and said "it will be some time before any definitive results are available" on their causes.
Boeing officials could not be reached immediately for comment.