The Federal Aviation Administration this week denied a report that the control tower at Burbank Airport was changing computer programs at the time a light plane flew into a mountain above Altadena, killing two men.
The only change in the system was made about 10 hours before the crash, an FAA spokeswoman said.
A Cessna 172, which had taken off from Van Nuys Airport and was headed for Santa Monica Airport, slammed into the San Gabriel Mountains on Oct. 16, killing Allen Hart, a flight instructor, and his student, August Henschell, both 24.
Both men were unfamiliar with the area. Henschell was from Austria. Hart, who had recently moved to Southern California from Florida, was working only his second day as a flight instructor and was flying under control of Burbank Airport FAA tower.
Hit at 3,000 Feet
The plane was heading east--away from Santa Monica--at 3,000 feet when it ran into the mountain, which is more than 5,000 feet high.
The National Transportation Safety Board is investigating the crash and exploring the possibility that work on the computer system at the control tower was related to the accident, FAA spokeswoman Elly Brekke said Monday.
An FAA spokesman was quoted in news reports last week as saying it was possible that, at the time of the crash, the tower's computer was being switched between two programs--one that had been used for several years, and a new program being introduced.
"Either inaccurate information was given out, perhaps by the FAA, or the information was misinterpreted," Brekke said. The spokesman quoted in the news reports has left the city for a week and was not available for comment, she said.
"It's true that a new software system was being tested," she said. The testing had been going on for several weeks, and switching between the two systems "had become routine--nothing unusual at all," she said.
It was necessary to switch to the older software system whenever computer technicians wanted to work on the newer system, she said.
On the day of the crash, she said, the computer was changed to the new program before 6 a.m., when there was little air traffic. The older program was brought back on line, at the request of the computer technicians, at 9:30 a.m., she said.
The Cessna did not crash until about 7:30 p.m., she said.
Only One Switch
"The system was not being switched back and forth," she said. "There was only that one switch that day."
During the switch, there would be a short period--30 seconds maximum--when neither system operated, she said, "so these switches were always coordinated in advance so that all the controllers were prepared."
"As far as we know," she said, the computer system was operating normally at the time of the crash.
The alternate use of the two computer programs came to an end Nov. 7, when tests on the newer program were completed and it permanently replaced the older one, she said.