The Civil Aviation Department (CAD) has been accused of a safety cover-up concerning its controversial air traffic management system (ATMS).
In a late-night statement on Wednesday, the aviation regulator confirmed that the much-criticized system was involved in six separate safety incidents last month which were not previously disclosed to the public, following a report by news agency FactWire.
Civic Party lawmaker Jeremy Tam Man-ho, who is also a pilot, hit out at the department for not being honest with the public. Tam previously helped whistle-blowers reveal a number of problems stemming from the HK$1.56 billion system.
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The incidents, known as "loss of separation" – a minimum distance for aircraft to reduce the risk of mid-air collisions – were reported to have occurred between January 13 and 30. The department classified them as "minor incidents" and "minor technical incidents."
The days spanned the Lunar New Year holiday, one of the busiest travel periods.
Earlier, the department had praised the reliability of the system over the holiday, during which record flight activity was recorded and air traffic services were maintained in a "safe and efficient manner".
Since the commissioning of the ATMS in November, it has developed a series of glitches including aircraft disappearing from radar, aircraft that did not exist appearing on radar, and the duplication of flight symbols on screens confusing controllers.
Further serious problems have overwhelmed the radar system and caused departing flights to be delayed.
A CAD spokeswoman said following an investigation there was "no evidence" to suggest that the six incidents were related to the new air traffic management system. She said other factors to consider included inclement weather and human factors.
On Tuesday, Professor Anthony Cheung Bing-leung, the secretary for transport and housing, toured the new air traffic control center.
Cheung, whose bureau oversees the department, said the ATMS was able to provide "safe and smooth" operations during the Lunar New Year.
It is not known whether the department disclosed the six reported incidents to Cheung on his visit or previously, if at all.
As members of the public were kept in the dark, the Transport and Housing Bureau said in a Wednesday night statement that the CAD would inform the bureau about safety-related incidents including those involving loss of separation, and therefore would have knowledge of what had occurred.
Lawmaker Tam said: "First they [the department] issued a statement to say they are proud they handled 2,000 flights in a day and that they have broken a record.
"But what they did not say was that they broke the record for the number of incidents. So you are hiding and covering up. It seems he [Cheung] was not aware of any incidents. It seems the department covered it up not only to the public, but also to the minister."
The six reported flight errors involved aircraft coming within five nautical miles of nearby aircraft and under 1,000ft.
The CAD did not name the airlines involved but referred to the dates of the incidents cited by FactWire.
Events recorded on January 13, 24 and 26 involved aircraft not meeting the minimum spacing for safe distances and were classed as "minor incidents".
On January 13, a HK Express plane from Tokyo and a Shenzhen Airlines flight from Quanzhou were only 3.8 nautical miles and 800ft apart some 75 nautical miles east of Hong Kong International Airport. In another incident on January 24, a Cathay Pacific cargo plane from Anchorage, Alaska, and a UPS freighter from Shenzhen to Clark in the Philippines were 3.8 nautical miles and 800ft apart only 30 nautical miles southwest of the airport.
Similarly, a business jet caught up with a Cathay Pacific aircraft from Beijing, meeting four nautical miles apart at 19,000 feet, around 40 nautical miles southwest of the airport.
The CAD said these incidents posed "no risk" to flight safety.
Other incidents on January 19, 27 and 30 involved loss of separation within a margin of tolerance which instead was classified as "minor technical incidents".
The CAD said even if air traffic controllers did not take remedial action, these would not result in collisions since the incidents were momentary.
This included two Cathay flights on January 27 from Osaka and Hokkaido that were 4.7 nautical miles and 500 feet apart. On January 30, a Cathay flight from Taipei and a Mandarin Airlines plane from Taichung had 4.4 nautical miles of separation at a distance of 800ft. A similar separation breach occurred on January 19 involving Xiamen Airlines and Shenzhen Airlines flights.
Post has contacted Cathay Pacific and HK Express for comment, pending a reply. All other airlines mentioned in the report could not be reached for comment.