Tuesday, September 25, 2007

FAA History Lesson -- September 25



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

”Sep 25, 1978: A midair collision over San Diego between a Pacific Southwest Airlines Boeing 727 and a Cessna 172 caused more fatalities than any previous civil aviation accident within U.S. airspace. All 137 persons aboard the two aircraft and seven on the ground were killed. Both aircraft were transponder equipped and were operating in clear weather under local air traffic control when they collided at 2,600 feet. Both pilots had been warned of the presence of the other aircraft. The PSA pilot, which was overtaking the smaller plane, had received clearance for visual, "see-and-avoid" separation procedures after reporting to controllers that he had the Cessna in sight.

The National Transportation Safety Board (NTSB) concluded that the accident’s probable cause was the PSA crew’s failure to comply with the provisions of a maintain-visual-separation clearance, including the requirement to inform the controller if they no longer had the other aircraft in sight. The Board cited as a contributing factor the procedures that allowed controllers to authorize visual separation procedures when the capability to provide radar separation was available.

NTSB member Francis H. McAdams dissented, citing the use of visual air traffic control (ATC) procedures as part of the probable cause rather than merely contributory. He also listed a number of contributing factors, mostly inadequacies of the ATC system. Among these were failure to resolve an automated conflict-alert alarm that the approach controller had disregarded on the assumption that the pilots were maintaining visual separation. (NTBS later adopted McAdams’ viewpoint in an Aug 1982 amendment that included both ATC and pilot failings in the probable cause finding.)

The San Diego accident followed another midair collision that had occured on May 10, 1978, between a Falcon Jet and a Cessna 150 over Memphis, Tenn., with the loss of six lives. The NTSB’s finding of probable cause in that case cited the failure of controllers to maintain proper separation as well as the pilots' failure to see and avoid each other. The two accidents set off intense criticism of FAA’s ATC program and the pace of its plans to develop an airborne collision-avoidance system. (See Dec 27, 1978.) ”


There was a very famous photograph of this accident and I could swear it made the cover of Time magazine. I couldn’t find the cover but I did find the Time article on the story while I was searching.

Don Brown
September 25, 2007

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