HONG KONG - An Air China passenger plane nearly hit a mountain on Lantau Island last Sunday (June 4), after taking off from Hong Kong International Airport and deviating from its flight path.

According to images released by flight tracking site Flightradar, flight CA428 turned south towards the Tai O fishing village, which is surrounded by mountains, instead of heading westwards along its normal route.

The South China Morning Post reported on Monday that an air control officer issued an immediate warning and asked the pilot to correct his flight path.

The Airbus 320, which has a seating capacity of 200, was at 3,400 feet (1,036m) when it turned.

Lantau Peak, the highest point on the island, stands at 3,064 feet.

Civic Party lawmaker Jeremy Tam Man-ho, a licensed pilot, told SCMP that the minimum safe altitude for the 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," Mr 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.

The plane eventually landed safely in China's Chengdu about two hours later.

An Air China spokesman said its pilot had queries about the air control officer's directions but made the decision to turn first due to a busy radio frequency.

"Air China has been putting air safety as our top priority," the spokesman added. "We will further strengthen our safety education."

In an audio recording of the conversation between the officer and pilot obtained by SCMP, the officer can be heard warning the pilot to "turn right immediately" and "expedite climb" due to the terrain.

The officer later said she would have to file a report about the turn, with the pilot subsequently apologising.