Crew error had not been ruled out. An investigation by the Brazilian Public Safety Ministry released in November 2008 concluded that the pilots mistakenly left the lever for the right engine to climb upon landing, due to a mistake in landing procedures with the right thrust reverser being disabled from a prior maintenance, when in fact it was necessary to retard both engines in order for the spoilers to work. They also said that the National Civil Aviation Agency should have closed the airport on the night the plane landed because of heavy rains; that Congonhas airport authorities shared the blame because its runway had not been properly constructed with grooves to drain away excess rainwater, contributing to the crash; that the plane's manufacturer, Airbus, should have provided alarms warning the pilots that the braking system was failing; and that TAM failed to properly train its pilots, who did not act correctly in the emergency. Final report In September 2009, more than two years after the accident, CENIPA announced the results of official investigations. The report shows that one of the thrust levers, which control engines, was in position to accelerate when it should be in idle, but it was not proved if there was mechanical or human failure as the cause of the accident. The report suggests two hypotheses for the accident. In the first, there was a flaw in the power control of the plane's engines, which would have kept one of the thrust levers into acceleration, regardless of their actual position. This scenario would implicate mechanical failure of the aircraft as the cause of the accident. The likelihood of this failure occurring is calculated at once per 400 billion flight hours, and therefore highly improbable. In the second hypothesis, the pilot has performed a procedure different from that provided in the manual, and put the thrust lever in an irregular position. This scenario would implicate human error as the cause of the accident. In addition to the positions of the thrust levers, the report points to several factors that may have contributed to the accident, such as a high volume of rain on the day, with the formation of puddles on the runway, as well as the absence of grooving. The report does not blame the length of the runway for the accident. The BEA also cleared Airbus of any misdoing because they had proposed a system