Air traffic controllers had told the planes that collided in Brazil's worst air disaster to keep altitudes 1,000 feet apart, the Air Force commander said Tuesday. A newspaper reported that the smaller jet may have violated those orders.
Investigators on Tuesday began examining voice and data recorders recovered from the planes, including the brand new Gol airlines Boeing 737-800 that crashed into the Amazon jungle with the loss of all 149 passengers and six crew members aboard.
The Embraer Legacy executive jet, on its maiden flight with seven aboard, was damaged but landed safely at an air force base.
"The Boeing had a flight plan for 37,000 feet (11,300 meters) and the Legacy jet was authorized to fly at 36,000 feet (11,000 meters)," the Air Force commander, Gen. Luis Carlos Bueno, said in an interview Tuesday with Brazil's government news service Agencia Brasil.
The Brazilian daily O Globo quoted unidentified government investigators as saying the Legacy had been authorized to fly to the Brazilian capital, Brasilia, at 37,000 feet. But the newspaper said the Legacy did had not responded to air traffic control orders to descend to 36,000 feet after that point.
Neither the Air Force nor the National Civil Aviation Agency would comment on the O Globo report. Bueno said investigation of the flight recorders should help clarify what happened.
Most of the victims apparently were Brazilian. The only American on the downed Boeing appeared to be Douglas Hancock, 35, of Missouri, who was living in Rio de Janeiro. Hancock was in Mato Grosso for business, his father, Paul Hancock, of Jackson, Missouri, told the Southeast Missourian newspaper.
Claudio Passos of the National Civil Aviation Agency said the flight recorders were in "perfect condition" and would be examined in Sao Jose dos Campos, not far from the crash site, and in Seattle, Washington, where the Boeing was manufactured.
Bueno said about 100 bodies were found within a kilometer (half mile) of the wreckage. He said rescue workers would have to make more clearings in the dense jungle to recover the rest.
The bodies were flown from the Jarina cattle ranch that has been used as a base of operations by Air Force rescuers. They were accompanied by three boxes of the victims' personal belongings: books, personal calculators, cameras, passports and handbags.
From there, Bueno said, they were being flown to the coroner's office in Brasilia for identification.
An official Air Force photo published Tuesday showed part of the shattered plane lying wheels up in the jungle.
Investigators also were questioning if the pilots were alerted by on-board equipment designed to set off an alarm if planes get too close.
John Hansman, an aeronautics professor at the Massachusetts Institute of Technology, said Monday that air traffic in Brazil is complicated in vast regions that are not covered by radar, especially over the ocean and in the Amazon jungle.
Pilots often propose a route and at certain waypoints check in with controllers who verify the plane's location, altitude and bearing.
The U.S. National Transportation Safety Board said it was sending a team of investigators, who would be joined by representatives from the Federal Aviation Administration and Boeing Co.
The U.S. agencies were involved because the Gol plane was manufactured in the United States and the smaller jet was registered there.
The jet disobeyed a control tower order to descend to a lower altitude just before impact.
Analysis of the flight data recorders indicated the smaller jet's transponder was not transponding at the time of the accident.
"The tower normally thinks of when an airplane is taking off and what is its final destination, but it isn't what determines the altitudes and course of things."