QUITO (Xinhua) -- An international commission investigating the Jan. 24 collision of two helicopters which killed 7 people, including Ecuadorian Defense Minister Guadalupe Larriva and her daughter, had ruled out a deliberate attack or mechanical failure as the cause of the accident, a spokesman for the commission said Friday.

The commission, known as the Special International Joint Air Accident Investigation Council (Jeiiaa), believes that a pilot error caused the two Gazelle helicopters to collide, Leonardo Barreiro, spokesman for the commission, said.

Barreiro said that the commission was now examining the trajectory of the aircraft from their takeoffs at the Montecristi Polygon to the Eloy Alfaro Airport in the coastal city of Manta.

Barreiro did not say which helicopter was responsible for the collision, however. Instead he confirmed that both motors were operating normally at the time of the collision, according to research by international experts.

The investigators have ruled out sabotage, because the aircraft parts had crashed onto a narrow area. The Jeiiaa will deliver its report in 15 days to the Ecuadorian military authorities.