Cathay Pacific is looking into a report from its cabin crew that several unidentified people mysteriously intruded on a landed plane.
The incident is apparently not isolated, as the leader of the Cathay Pacific Airways Flight Attendants Union says the strange happenings have cropped up several times a day since around Monday, after most or all of the passengers had left the cabin after landing.
And the intrusions were spreading fear among the crew, union chairwoman Dora Lai Yuk-sim said.
"Sometimes they're in suits and sometimes they're in casual wear," Lai said.
"Two or three of them storm into the cabin without telling the crew who they are and what they are there for.
"They walk from the front of the cabin to the end of it. They appear to be looking for or inspecting something. But they do not take anything away."
When some flight attendants asked who the people were, they either refused to answer or replied "ground staff" before walking away, she said. There were both men and women among the trespassers and they appeared to be Hongkongers.
"They cannot be our ground staff because ours wear Cathay uniforms," Lai said.
An in-flight service manager has made a report to the management about one such incident.
A Cathay spokeswoman confirmed it had received a report on the matter. She said the intruders were not airline employees.
"We have been notified of a single report, which we will follow up on promptly," she said.
"There are no further details available at this point and should this become a formal investigation, we would be unable to comment further."
She declined to say if Cathay had made a police report.
Lai expressed concern about airport security because the unidentified individuals had to be either tourists or airport employees to enter the restricted arrival area of Chek Lap Kok.
She had not witnessed the incidents herself, she said, but several flight attendants on both short- and long-haul flights from, for example, London and Kuala Lumpur, had seen these people and told her.
Some flight attendants who asked not to be named suspected that the intruders were colleagues sent by the management to check if cabin crew were removing on-board refreshments such as wine and caviar.
Earlier this month, the airline e-mailed all in-flight service managers saying they should call security if they saw anyone take away airline "property".
It did not define what it meant by "property", but the flight attendants said they believed the e-mail was referring to food, since the "takeaway" practice had existed for a long time.
One of the flight attendants said: "Some crew members said Cathay fired a cabin crew member after the airline suspected she took away airline property about half a year ago. The flight attendant was not caught red-handed but she was eventually fired because of 'loss of trust'."
An Airport Authority spokesman said it was not aware of the alleged incidents. The police said they could not comment unless more information was available.