Tuesday, December 18, 2007

FAA History Lesson -- December 18



From the FAA Historical Chronology, 1926-1996...


”Dec 18, 1992: Eight fatalities occurred when a Cessna 550 crashed after encountering wake turbulence behind a Boeing 757 during descent into Billings, Mont. The National Transportation Safety Board subsequently cited the probable cause as the pilot’s failure to follow established wake turbulence procedures. Nevertheless, the accident increased concerns that 757 wake turbulence might represent a special problem, an issue raised within FAA by Chief Scientist Robert Machol. (See Nov 1, 1975, and Dec 15, 1993.)”

” Dec 15, 1993: Five persons died when an Israel Westwind aircraft following a Boeing 757 encountered wake turbulence and crashed at Santa Ana, Calif. The National Transportation Safety Board later found the probable cause to have been the Westwind pilot’s failure to maintain adequate separation behind the 757 and/or to remain above its flight path during approach. The Board considered a related factor to be inadequacy of air traffic control procedures regarding visual approaches and visual flight rules operations behind heavier airplanes. On Dec 21, meanwhile, FAA required air traffic controllers to issue wake turbulence advisories to aircraft following 757s in all cases for which such advisories would be issued for jets heavier than the 757. On Dec 22, FAA sent a letter to licensed pilots alerting them to accidents and incidents involving 757 wake turbulence and urging attention to existing guidance on avoiding wake hazards. (See Dec 18, 1992, and May 20, 1994.) “

I’m guessing Marion Blakey never read about these two accidents. Otherwise, she wouldn’t have been saying this on PBS’s New Hour.

”And the system we're talking about, ultimately, because it is much more precise than radar means you're going to be able to bring aircraft closer together, and that means you can get more up there. So all of this goes to improvements.“

We can “get more up there” all right. It’s getting them back on the ground that is the problem. Unless NextGen can make more runways or cure wake turbulence, it won’t do a thing for airline delays.


Don Brown
December 18, 2007

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