An Air China passenger plane almost hit a mountain on Lantau Island on Sunday night when it deviated from its flight path after taking off from Hong Kong International Airport, it was revealed on Monday.
Images from aircraft tracking site Flightradar showed flight CA428 turning south towards Tai O village and the surrounding mountains at around 9.30pm, instead of continuing westwards along the normal route until it left the island.
An air control officer was forced to issue an immediate warning and set of directions to the pilot to correct the flight path.
The Airbus A320, with a seating capacity of 200, landed safely in China’s western city of Chengdu about two hours later.
It had been at 3,400 feet during the wrong turn. The peak nearby – the highest point on Lantau – is 3,066 feet. But according to Civic Party lawmaker Jeremy Tam Man-ho, a licensed pilot, the minimum safe altitude for that area is 4,300 feet.
“If the plane was carrying more cargo or passengers, or if the plane was a bigger one, it might not have achieved its altitude at that time,” Tam said. “If the plane turned towards the mountains at an even lower altitude, you could imagine what the consequence could have been.”
But he added that an anti-collision system on the plane would have directed it to climb up immediately before any mishap.
Air China said the flight crew had questions about the air traffic control officer’s directions but, due to a busy radio frequency, the pilot decided to turn first while still confirming the directions.
“Air China has been putting air safety as our top priority,” a spokesman said. “We will further strengthen our safety education.”
Tam suggested there was no reason why the pilot should have deviated from the normal route. Even if there was a radio failure, he should have stuck to the normal departure path, he said.
Tam earlier shared an audio recording of a conversation between the air traffic officer and the pilot, in which the officer is heard issuing repeated directions to “turn right immediately”, warning of “terrain ahead”. When the pilot does not turn, she can be heard warning of the mountains again and requesting he climb to 5,000 feet immediately.
After the pilot corrects the mistake, the officer tells him she will have to submit a report about the incident to authorities. The pilot can be heard apologising.
What was said
14:11Officer: Air China 428, turn right immediately. Turn right immediately. Heading 0 caution 270. Terrain ahead, expedite climb.
14:20Officer: Air China 428.
14:24Officer: Air China 428, expedite climb. Terrain ahead. Terrain alert. Expedite climb passing 5,000 feet. Expedite.
31:43Officer: Air China 428.
31:45 Pilot: Hey, here is Air China 428.
31:47 Officer: Um, we will have to file a report about the turn just now so, um, just to let you know.
31:53 Pilot: Um, sorry. OK, I got it.
Tam said he could not draw any conclusions on how and why the incident happened, but said there were a few possibilities, including that the pilot misheard an instruction asking him to turn 130 degrees, believing he had been told to climb to 13,000 feet.
He said the pilot could even have pressed a wrong button, because the climb and turn buttons were next to each other in the cockpit.
A third possibility was that the autopilot system had been wrongly set before take-off, Tam said.
A Hong Kong Civil Aviation Department spokesman said the air traffic control officer had found the plane deviating from its normal path after she directed the pilot to climb up to 13,000 feet. He said the officer then directed the pilot back to the correct path.
“We need to give our frontline air control officers credit for acting professionally and giving clear directions calmly,” Tam said.
“No one was injured during the incident,” he said. “The safety of other planes in Hong Kong’s airspace was not affected. There was no risk of collision between the aircraft concerned and other aircraft or buildings, as the minimum separation was maintained at all times.”
The spokesman said the department had requested Air China submit a report and inform the Civil Aviation Administration of China about the incident. He added that the department would follow up on the incident and take proper action based on set procedures.
The pilot sought to land on the south runway at the airport, but at the same time a plane was ascending from the south runway. Air traffic controllers had to instruct the departing aircraft to stop climbing immediately. It was later found that the pilot had mistakenly picked up instructions from the control officers intended for another flight. The pilot was subsequently suspended. -SCMP –