Half of the airport systems used to detect rapid changes in winds weren't working at the time of a deadly crash in southern Thailand, a government official said Tuesday.

Buddhist monks pray for the dead early on Tuesday at the airport in Phuket, Thailand.
(David Longstreath/Associated Press)

Investigators are still working to determine the cause of Sunday's crash at the airport on the resort island of Phuket.

A Vancouver woman, Larisa Fayed, is feared among the 89 dead. Her name was on the passenger list and she has not been heard from since the One-Two-Go Airlines plane carrying 130 people skidded off the runway and hit a retaining wall after landing.

The plane split in two and quickly filled with smoke and fire.

Investigators have said wind shear — a sudden change in wind speed or wind direction in an airplane's flight path — could be a cause for the crash, which occurred in a heavy rainstorm.

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

He said the solar-powered systems were out at the time of the crash, which would have made it difficult for pilot Arief Mulyadi to judge whether attempting to land would be safe. Mulyadi, who died in the crash, has been criticized by some transport officials for landing despite warnings from the flight tower about treacherous wind shear.

The two black boxes were retrieved from the wreckage and are being sent to the United States for examination.

No official word on missing Canadian's status

Forty-one people survived Sunday's crash, including Mildred Anne Furlong, a 23-year-old waitress from Prince George, B.C., who escaped through a window.

Several news reports have said there is still one unidentified survivor, and the father of the missing Vancouver woman said he's praying it is his daughter.

The Canadian Foreign Affairs Department has confirmed two Canadians were on the plane, but have not identified Furlong by name, or released her status.

According to the passenger manifest, Fayad was listed in seat 6D, near the front of the plane. Her bags were tagged and weighed for the flight.

"She was on the flight and she's on the victims' list but I don't know if it's been confirmed or not," her father, Foued Fayad, told CBC News on Monday night.

'It's the worst day in my life. I am numb.'—Foued Fayad, Larisa Fayed's father

"It's the worst day in my life. I am numb. I don't know, I can't find the words to describe it. She was my first daughter. My daughters are my life."

Larisa Fayed, a 31-year-old technical and lighting director, was in Thailand for a short vacation after travelling in the Philippines for a performance with a Vancouver dance troupe called Erasga.

Sunday's crash was the deadliest in Thailand since Dec. 11, 1998, when a Thai Airways plane crashed in Surat Thani in southern Thailand, killing 101 people on board. Forty-five people survived.

With files from the Associated Press