Missing screws under a platform of the moving walkway were the cause of the incident at Don Mueang Airport that cost a woman a part of her left leg on June 29, an observer in the fact-finding probe said on Friday.
Assoc Prof Weerachai Phut-dhawong, a lecturer of the Chemistry Department at Kasetsart University's Faculty of Liberal Arts and Science, said it really was an accident.
Assoc Prof Weerachai was appointed by the victim's family to join the fact-finding committee, which also comprises the Ministry of Transport, the Engineering Institute of Thailand (EIT), the Engineers Council and the Siam Hitachi Company.
The incident occurred last Thursday around 8.40am in the South Corridor of the domestic terminal at the airport. The injured woman is being treated in an ICU room at Bumrungrad International Hospital.
Speaking after the committee meeting on Friday, Assoc Prof Wee-rachai said the mechanical failure might have been caused by missing screws under the platform.
He said normally, each panel of the moving walkway has been tightened with four screws, but the panel that the woman stepped on had only one screw. Three screws were missing, so when she stepped on the panel, it fell while the walkway was still moving and trapped her leg.
"I view this as an accident, and it has nothing to do with luggage or the missing comb of the travellator. The travellator had been used for almost 30 years, and the sensor system was functional as it stopped the walkway in 10 seconds," he said.
However, the 10 seconds seemed to be too long as it appears to have cost the woman her leg, he said.
He said everyone on the scene, including four flight attendants and technicians rushed to help the victim at that time.
The question is how those screws went missing, he said, surmising it might be because the moving walkway was too old.
Meanwhile, Kit Kittirattana, the victim's son, thanked Assoc Prof Weerachai in a Facebook post for proving his mother was not at fault by looking at whether the incident was caused by carelessness on her part or the fault of a certain agency.
"I urge the fact-finding committee to inspect the matter thoroughly to prevent the recurrence of such an incident," he said.
Mr Kit also said Assoc Prof Wee-rachai proposed the committee re-enact the incident and it will hold at least two more meetings, adding that Airports of Thailand is preparing to issue a statement admitting fault and taking full responsibility for the accident.
"My mother is recovering after being treated in an ICU room for four days," he added.