Vietnam Airlines has suspended a flight crew pending a procedural investigation into an emergency landing that took place on Tuesday night.
Spokesman Le Truong Giang said Wednesday that the airline suspended Czech captain Pechanec Marek and his co-pilot Do Hoang Nam and five other crew members.
The suspension will last until the conclusion of an investigation by the Civil Aviation Administration of Vietnam (CAAV), Giang said.
The investigation’s results will make it clear whether Captain Marek erroneously pressed the hijacking distress button (7500) instead of the emergency landing button (7700) as reported by local media, he said.
On Wednesday, the CAAV said its investigative team, led by CAAV's deputy director Do Quang Viet, began uploading information from the flight recorder and taking verbal accounts from the flight crew.
It also said the emergency landing had nothing to do with hijacking.
The crew's Airbus A321 left Ho Chi Minh City at 5:12 PM for Vinh, the capital city of the north-central province of Nghe An, and encountered technical problems above the airport in Nghe An.
The incident led to a sudden drop in cabin pressure, forcing the pilots to descend from 35,000 feet to 13,000 feet, according to a Vietnam Airlines statement released late Tuesday.
Oxygen masks were deployed for the passengers and the crew, the statement said.
The cabin crew then requested permission to make an emergency landing at Noi Bai International Airport in Hanoi to ensure the best possible ground support, according to the statement.
The plane, its 135 passengers and seven crew members, landed safely at Noi Bai at 7:15 pm.
According to Vietnam Airlines, the plane has been in use since 2008.
Of 135 passengers, 26 remained at Noi Bai while the others boarded a Vinh-bound plane that took off at 9:50 pm on Tuesday.
But Nguyen Thanh Trung, a former deputy general director of Vietnam Airlines, told news website VnExpress it was unlikely the pilot pressed the incorrect emergency code button as they are spaced far apart.
He said a drop in cabin pressure is typically caused by a leaky gasket.
Trung also said the pilots took the right course of action by asking for permission to urgently land at Noi Bai airport.