The number of aircraft near-misses in Hong Kong’s airspace rose to a six-year-high in 2017, following the introduction of the troubled new air traffic management system in late 2016, official figures obtained by FactWire reveal.

According to the Civil Aviation Department (CAD), in 2017, there were 17 “loss of separation” incidents – when aircraft came too close to one another – up from 10 in 2016, when the old system was still in use.

The number of momentary violations of safe distances – classified as “minor technical incidents” by the CAD – also increased to 12, which was three to four times the figures in the previous three years.

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Hong Kong airport’s new $1.56 billion air traffic management system was fully commissioned in November 2016. Photo: Pool.

Both figures were the highest since 2012, as one air traffic controller told FactWire that Hong Kong airspace has become “very unsafe.”

“The number of safety incidents is to a certain extent indicative of the chances of a plane crash in that airspace,” he said.

As defined by the International Civil Aviation Organization, a “loss of separation” incident occurs when the distance of two airplanes is less than the minimum requirement of five nautical miles horizontally or 1,000 feet vertically.

The CAD also classifies cases as minor technical incidents when the safe distance infringement is momentary, less than 10 per cent of the standard separation, and does not pose any risk of collision even if no remedial action is taken.

There were already two cases of ‘loss of separation’ and four “minor technical incidents” in the first quarter of 2018, according to the CAD.

The latest figures have raised further safety concerns over Hong Kong airport’s new $1.56 billion air traffic control system.

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The number of loss of separation incidents in Hong Kong airspace rose to a six-year-high in 2017. Graphic: FactWire; source: Civil Aviation Department.

In February last year, FactWire revealed that the CAD tried to cover up six “loss of separation” incidents that happened in January alone – a frequency senior air traffic controllers described as “rare and unacceptable.”

At the time, sources said the system’s failure to issue timely “conflict alerts” was to blame.

But the CAD insisted that alerts were issued “in a timely manner as per system design,” adding that three of the six cases FactWire revealed were only “minor technical incidents.”

It said “losses of separation” were due to a number of factors such as adverse weather, operating procedures and human factors and they did occasionally occur due to the old air traffic system and other systems around the world.

“The department would investigate every individual incident according to established procedures and make necessary improvement,” the department added.

Founded in 2015 and funded by the public, FactWire is a non-profit investigative news agency.