An ATR-72 turboprop plane operated by regional airline company Voepas crashed into a residential area near Sao Paulo, Brazil on Friday, killing all 62 passengers on board.
Cenippa, the head of Brazil’s aviation accident investigation center, said on Sunday that investigators had recovered the plane’s so-called black box, which contains voice recordings and flight data. A preliminary report is expected within 30 days.
How did the accident happen?
The plane was flying from Cascavel in Parana state to Sao Paulo and crashed at about 1:30 pm (1630 GMT) in Vinhedo, about 80 km (50 miles) northwest of Sao Paulo.
The Brazilian air force said in a statement that the plane was flying normally until 1:21 p.m. when it stopped responding to calls and lost radar contact at 1:22 p.m. The plane did not report any emergency.
Video of the incident shows the skies were clear when the plane began the unusual circling.
What will the experts find?
US aviation safety expert Anthony Brickhouse said investigators would look at factors such as the weather and the extent to which the engines and controls were functioning properly to try to determine what caused the loss of control.
Could weather conditions be a cause of the accident?
Video of the crash analyzed by aviation experts led some to speculate that the plane had accumulated ice. On Friday, Voeppas said there was ice accumulation at the altitude at which the plane was flying, but that it should have been within acceptable levels.
Brazilian aviation engineer and accident investigator Celso Faria de Souza said looking at the video he was almost certain that ice was the cause of the crash.
ATR-72s have experienced problems with icing, with 68 people killed in a 1994 crash in the US state of Indiana after the plane was unable to bank due to ice build-up. After that incident, manufacturer ATR improved its de-icing system. In 2016 an ATR-72 in Norway had problems after ice built up on the plane, but the pilot was able to regain control.
Could the engine have failed?
John Hansman, a professor in the Department of Aeronautics and Astronautics at the Massachusetts Institute of Technology, reviewed some of the footage of the Brazil crash shared on social media and said without reviewing the flight data that the crash was not caused by weather.
Hansmann said there may have been an engine failure on one side that the crew did not manage properly, causing the plane to spin downward.
Are multiple points of failure possible?
According to experts, plane crashes can happen for a variety of reasons. These can include ice, engine failure or human error. In many cases, there is more than one cause, said Robert A. Clifford, a lawyer who represented some of the families of victims in the 1994 crash.
(Except for the headline, this story has not been edited by NDTV staff and is published from a syndicated feed.)
