Investigators seek cause of Brazil aircraft crash that killed 61 on board

No alarm reported from crew of ATR propeller plane before it went into a spin and crashed in Sao Paulo state

Authorities and aviation experts struggled on Saturday to piece together what caused a plane crash in Brazil's Sao Paulo state that killed all 61 people on board.

The ATR 72 twin-engined propeller aircraft operated by regional airline Voepass was heading to Sao Paulo’s international airport with 57 passengers and four crew members when it crashed in the city of Vinhedo on Friday.

Video shared on social media showed the ATR-72 aircraft spinning out of control as it plunged down behind a cluster of trees, followed by a large plume of black smoke.

The aircraft smashed into the compound of a gated community but caused no injuries on the ground.

City officials at Valinhos, near Vinhedo, said there were no survivors and only one home in the housing complex had been damaged.

A resident of a nearby building, Daniel de Lima, said he heard a loud noise before looking outside and seeing the plane in a horizontal spiral.

“It was rotating, but it wasn't moving forward,” he told Reuters. “Soon after it fell out of the sky and exploded.”

“I almost believe the pilot tried to avoid a nearby neighbourhood, which is densely populated,” he said.

The head of Brazilian aviation accident investigation centre, Cenipa, said the plane's black box containing voice recordings and flight data had been recovered from the site.

The plane's unusual final circling motion triggered widespread curiosity among aviation experts, especially given a lack of bad weather.

US aviation safety expert Anthony Brickhouse said investigators would look at things like weather and whether the engines and controls were functioning properly as they examine causes for the loss of control in flight.

“From what I've seen it was definitely what we would call loss of control,” he said.

Flightradar data showed significant gyrations in speed before the crash, US aviation safety consultant and former commercial pilot John Cox said.

He said he would want to verify the data but that something “really significant” happened to cause the plane to spin when it came down.

“It appears that there may have been some catastrophic event before that loss of control,” he said.

The crash was the world's deadliest airline since January last year, when a Yeti Airlines plane in Nepal stalled and crashed while making its landing approach, killing 72 people on board. That plane also was an ATR 72, and the final report blamed pilot error.

A report Friday from Brazilian television network Globo’s meteorological centre said it “confirmed the possibility of the formation of ice in the region of Vinhedo,” and local media quoted experts who pointed to icing as a potential cause for the crash.

Marcelo Moura, director of operations for Voepass, told reporters on Friday night that, while there were forecasts for ice, they were within acceptable levels for the aircraft.

Lt Col Carlos Henrique Baldi of the Brazilian Air Force’s centre for the investigation and prevention of air accidents, told reporters that it was still too early to confirm whether ice caused the crash.

The plane is “certified in several countries to fly in severe icing conditions, including in countries unlike ours, where the impact of ice is more significant”, he said.

The centre said earlier that the plane’s pilots did not call for help nor say they were operating under adverse weather. There has been no evidence that the pilots tried to contact controllers of regional airports, either, Ports and Airports Minister Silvio Costa Filho told reporters Friday night in Vinhedo.

Brazil’s Federal Police said it was conducing its own investigation and had sent specialists in plane crashes and the identification of disaster victims to the crash site.

French-Italian plane manufacturer ATR said the company's specialists were “fully engaged to support both the investigation and the customer”.

The ATR 72 generally is used on shorter flights. The planes are built by a joint venture of Airbus in France and Italy’s Leonardo.

With reporting from Associated Press and Reuters