Flight recorder transcripts from the deadly July plane crash at Sao Paulo's Congonhas airport revealed Wednesday that mechanical failure may have caused the accident.

The transcripts, presented to a congressional commission investigating air safety in Brazil, showed the pilots were unable to activate the spoilers—aerodynamic brakes on the plane's wings—as they sped down the short runway in the rain.

"Only one reverser. Spoiler nothing," said pilot Henrique Stephanini Di Sacco, 53, moments before the crash.

"Look at that. Slow down, slow down," said co-pilot Kleyber Lima, 54.

Di Sacco replied that he could not slow down. Amid shouts of "Turn!" from Lima, the recording ends with screams, a woman's voice and an explosion.

On July 18, the Tam Airbus 320 burst into flames when it slammed into a gas station and a Tam Airlines building after narrowly clearing the airport's perimeter fence and rush-hour traffic on a highway. The crash claimed the lives of all 187 aboard and 12 people on the ground.

The commission's president, Marco Maia, said he believed mechanical failure was behind the crash.

"From what we have determined, we can confirm that the machine failed," he said, adding that investigators must still "thoroughly examine all the possibilities."

Brazilian newspaper Folha de S. Paulo reported that according to the flight data recorder, one of the plane's throttles was in the wrong position as the flight landed, causing the jet to speed up instead of slow down

Video footage of the crash shows the plane speeding down the runway instead of slowing.

Brazilian aviation consultant Elias Gedeon said there were signs that the plane's computer system read the throttle position as an indicator the pilot was trying to take off again and disabled the spoilers. He added that it was too early to confirm this speculation.

The airline said previously that one of the jet's thrust reversers, used for braking, had been deactivated before the crash. Planes are allowed to fly this way, but it can make braking more difficult.

With files from the Associated Press