After their first investigations airline officials and experts reported that the TAM Flight 3054 had a faulty reverse thruster that was turned off when it landed.

The problem was confirmed by TAM vice president Ruy Amparo, who said a problem with one of two reverse thrusters was found four days before the crash, but under maintenance rules approved by Brazilian aviation authorities the planes are allowed to fly 10 days with this type of defect.

A security video released earlier this week by the air force showed TAM Flight 3054 speeding down the tarmac more than four times as fast as other planes landing around the same time.

The crash occurred in wet conditions, on a recently resurfaced runway that still lacked slashes - known as grooving - meant to facilitate drainage on rainy days and its has also been criticized as being too short.

Another possible cause of the Brazil’s worst aviation accident might be a pilot error, but Elnio Borges, president of the Varig Pilots' Assn dismissed the allegations.

"The government is clearly trying to convince public opinion that the runway at Congonhas was not at fault," he said. "They're going to do everything they can to blame the pilot."

The aircraft's flight recorder was found shortly after the crash and was set to be sent to the United States on Thursday.

On Wednesday, Brazil’s attorney general requested officially the closure of Sao Paulo airport until "impeccable security measures are in place and confirmed, and until all doubts are removed.”

According to the latest official figures, 187 people have already been confirmed dead, but the forensics experts have received 173 bodies and only 13 have so far been identified.

On Friday, President Luiz Inácio Lula Silva is expected to give a televised speech in his first public address since the crash and will address air safety concerns.