SÃO PAULO, Brazil — A Brazilian report issued Wednesday on the collision of an American-owned business jet and a Brazilian Boeing 737 airliner over the Amazon in September 2006 put part of the blame on the American pilots for apparently turning off cockpit equipment meant to alert other planes to its presence.
But a dissenting report by the United States National Transportation Safety Board on Wednesday put the main responsibility on the Brazilian air traffic control system.
The crash killed all 154 people on the airliner, a Boeing 737 operated by Gol Linhas Aéreas Inteligentes. The business jet, manufactured by Embraer, a Brazilian company, was being flown home by the American buyers, a charter company in New York. It was forced to make an emergency landing. The transponder, the equipment that was switched off, was American-built.
A transponder answers calls from ground-based radar and other planes and replies with the identity of the plane and its altitude, allowing the plane’s position to be determined. The transponder’s signals are recorded by the ground-based air traffic system.
The Brazilian report said the business jet’s transponder was running early in the flight, then it was off and then on again. The report said the cockpit voice recorder recorded Jan Paul Paladino, the second in command, when he let out an “exclamation” on noticing that it was not working after the collision.
After a silence of 10 seconds, Mr. Paladino said, “I’ll do that, I got that,” and the transponder was switched on, the report said.
Brig. Jorge Kersul, the head of the Brazilian safety organization, known by its acronym Cenipa, would not speak to reporters via telephone. But he told reporters in Brasília, the capital, that the transponder was switched to “standby” by mistake.
“There is nothing that proves this was intentional," Brigadier Kersul told the newspaper Folha de São Paulo. “No sound, no movement,” he said. “There is no reason for them to do that. The most probable hypothesis is that it was turned off inadvertently.”
In Washington, the National Transportation Safety Board, which is involved in the case because of the American components, said it agreed with the Brazilians’ factual findings. But it stressed that “the primary mission of air traffic control to separate aircraft within positive controlled airspace was unsuccessful.”
The Brazilian controllers, it said, had failed to act promptly when the transponder stopped working, and two-way radio voice communication ceased. Faulty software design at the air traffic control center may have contributed to confusion among the controllers about the plane’s altitude, the report said. The air traffic control system had been recently modernized.
The crew of the business jet was “not in violation of any regulations,” the American report said. The Americans said that they agreed that “safety lessons in these areas can be determined to better prepare flight crews for international operations.”
The Brazilians helped the Americans to draft a recommendation to the United States Federal Aviation Administration to require computerized airplanes to sound a prominent warning if the transponder is not running, the American report said.
According to the American report, both planes were assigned by air traffic control to operate in opposite directions on the same path and at the same altitude. “The loss of effective air traffic control was not the result of a single error, but a combination of numerous individual and institutional air traffic control factors, which reflected systematic shortcomings in emphasis on positive air traffic control concepts,” the American report said.
The American captain, Joseph Lepore, still flies for the charter company, Exelaire, of Ronkonkoma, N.Y. Mr. Paladino flies for American Airlines.
