FAA eases turbulence rule for Boeing's 747-8
The Federal Aviation Administration dropped a requirement that Boeing's latest version of the jumbo jet, the 747-8, must keep at least 10 miles separation from other airplanes. Now it will require just 4 miles of separation from heavy jets and up to 6 miles from light aircraft.
Seattle Times aerospace reporter
The Federal Aviation Administration (FAA) on Tuesday dropped a requirement that Boeing's latest version of the jumbo jet, the 747-8, must keep at least 10 miles separation from other airplanes.
The decision was backed by the International Civil Aviation Organization (ICAO), a United Nations agency that codifies the principles underpinning global air-navigation rules.
ICAO wrote to all member nations saying that a team of wake experts had examined flight-test and simulation data, and determined the 747-8 should be in the same class as its predecessor, the 747-400, and retain the same separation distances: just 4 miles separation from other heavy jets and up to 6 miles from light aircraft.
The ruling comes less than a week before the first delivery of the freighter version of the new jet, to Cargolux of Luxembourg, set for Monday.
Todd Zarfos, vice president of engineering on the 747-8 program, said Boeing customers will be able to operate the 747-8 in the same markets and routes they use for the 747-400, and that airports "will not have to slow down operations to accommodate this airplane."
The FAA had imposed the restriction last fall while the 747-8 was undergoing flight tests, requiring that planes landing behind the massive jumbo jet keep their distance to avoid turbulence from wake vortices
The safety agency said then that the interim separation standards were "conservative" and that analyses of computational models suggested the 747-8 wake vortices are similar to those generated by the 747-400 jet.
Subsequently, a special ICAO team including wake experts from the FAA, the European Aviation Safety Agency and Boeing "examined flight test and simulation data and established safety case arguments for ... operations of the Boeing 747-8 relative to other aircraft," the ICAO letter said.
"We did extensive testing to show that even though the 747-8 is longer, heavier and has a bigger wingspan than the 747-400, it does not create greater wake vortex effects," Zarfos said.
Dominic Gates: 206-464-2963 or firstname.lastname@example.org
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