Officials are saying that the systems that detect wind shear were malfunctioning at the time of the deadly Phuket crashed that killed 89 people on Sunday. 41 passengers on the One-Two-Go flight from Bangkok to Phuket survived the crash.

Investigators have said wind shear - a sudden change in either wind speed or direction in an aircraft's flight path that can destabilize a plane - was among the possible causes of the crash.

"Three out of six low-level wind shear alert systems were not working at the time," said Vuttichai Singhamanee, director of flight standard bureau of Transport Ministry's Aviation Authority Department.

Vuttichai said the solar-powered systems - which were out of power at the time of the crash - could have made it difficult for the pilot Arief Mulyadi, to judge whether it was safe to land. Mulyadi, who died in the crash, had been criticized by some Transport Ministry officials for landing despite warnings from the flight tower about treacherous wind shear.

While it is too early to definitively say what caused the crash, Kajit Habnanonda, president of orient-Thai Airlines, which owns One-Two-Go, also pointed to wind shear as a possible factor.

"The pilot who flew the doomed aircraft was one of our best. He was very experienced, patient and very decisive," Kajit told The Bangkok Post newspaper.

"There was no way of knowing in advance what sort of obstacles lay ahead for any pilot," he said.