Confusion over landing path
"I say again, turn!" the air traffic controller called over the radio, his voice rising, as the flight from Bangladesh swerved low over the runway at Kathmandu's small airport.
Seconds later, the plane crashed into a field beside the runway, erupting in flames and leaving 49 of the 71 people on board dead
That moment Monday appeared to result from minutes of confused chatter between the control tower and the pilot of the US-Bangla passenger plane, as they discussed which direction the pilot should use to land safely at the airport's single runway.
A separate radio conversation between the tower and at least one Nepali pilot reflected the sense of miscommunication.
"They appear to be extremely disoriented," a man said in Nepali, watching as Flight BS211 made its approach, though it was not clear if the voice belonged to a pilot or the tower. "Looks like they are really confused," said another man.
In the recording, posted by air traffic monitoring website liveatc.net, the pilot and the tower shifted back and forth about whether the pilot should approach the runway from the north or the south.
Just before landing, the pilot asked, "Are we cleared to land?"
Moments later, the controller came back on the air, his voice clearly anxious, and told the pilot, "I say again, turn!" Seconds after that, the controller ordered firetrucks onto the runway.
The plane, which was heading from Bangladesh's capital, Dhaka, to Kathmandu, was carrying 67 passengers and four crew members.
Kathmandu officials and the airline laid the blame for the accident on each other.
The airport's general manager told reporters Monday that the pilot did not follow the control tower's instructions and approached the runway from the wrong direction.
"The airplane was not properly aligned with the runway. The tower repeatedly asked if the pilot was OK and the reply was 'Yes,'" said the general manager, Raj Kumar Chetri.
But Imran Asif, CEO of US-Bangla Airlines, told reporters in Dhaka that "we cannot claim this definitely at the moment, but we are suspecting that the Kathmandu air traffic control tower might have misled our pilots to land on the wrong runway.
After hearing the recording between the tower and the pilots, "we assumed that there was no negligence by our pilots," he said.
He said the pilot, who survived the accident, was a former air force officer. Capt. Abid Sultan had flown the Bombardier Q400 series aircraft for more than 1,700 hours and was also a flying instructor with the airline.
Prior to the crash, the plane circled Tribhuvan International Airport twice as it waited for clearance to land, Mohammed Selim, the airline's manager in Kathmandu, told Somoy TV.
Nepal's government has ordered an investigation into the crash.
US-Bangla operates Boeing 737-800 and smaller Bombardier Dash 8 planes, including the Q400, the model that crashed.
Kathmandu's airport has been the site of several deadly crashes. In September 2012, a Sita Air turboprop plane carrying trekkers to Mount Everest hit a bird and crashed shortly after takeoff, killing all 19 people on board.
Pilot: Landing on 02. Bangla Star 211.
Tower: Runway 02 is clear to land Bangla Star 211
(conversation between air traffic controllers in their local language..)
Tower: Can you hold your current position?
Pilot : Sir are we clear to land?
Tower: Bangla Srtar 211 , I say again, turn ...)