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Francis Neoton Cheung is looking beyond the third runway in his vision for Hong Kong.

The recently released results of the Environmental Impact Assessment (EIA) for the Airport Authority’s proposal to add a third runway to the airport at Chek Lap Kok (CLK) has brought the long-simmering disagreement over the conservation value of marine wildlife to a boil. Yet, this important discussion may end up distracting the community from a much more fundamental question: is adding a third runway a strategically sound approach to meeting Hong Kong’s long term air traffic growth demand?

When the Airport Authority first broached the subject of expansion, only two options were presented to the public: either expand capacity while retaining the current two-runway system or build a third runway by reclaiming land in the ecologically sensitive waters off Lantau Island.

Assuming for now the projected demand figures are accurate, adding a third runway would only take us to the year 2030. What are we supposed to do after that? Indeed, by the time the proposed third runway goes into operation, 2030 would likely be less than a decade away. Taking a page from our ever-prudent Financial Secretary John Tsang, I believe the community should demand a more long-term vision and solution for the air traffic handling capacity.

Not radical; reasonable
Rather than limiting our options to two versus three runways at CLK, we should include the possibility of building a second airport as a way of increasing handling capacity. This out of the box idea is not as radical as it may sound at first blush if the inherent design limitations of a three-runway system are properly appreciated.

Most major international airports in the world, including the one at CLK, have adopted a configuration with one or more pairs of parallel runways functioning in tandem. This configuration offers an effective and efficient way of handling traffic by minimizing clearance time intervals. In busy airports such as the Hartsfield Jackson International Airport in Atlanta, the JFK International Airport in New York, or the Barajas International Airport in Madrid, two pairs of a total of four runways operate as a “dual-dual”, with the two tandems sufficiently spaced apart to avoid air space intrusion and to satisfy minimum requirements of the approach funnel. These airports effectively operate as two “separate” airports, though with the advantage of sharing common terminals and the use of the same land-side facilities.

3 runways rare
The configuration of three parallel runways in close proximity within a single airport is not common.  For safety reasons, the simultaneous landing or taking off of two aeroplanes, in any combination, is frowned upon and not practiced. A third runway, for this and other reasons, cannot add capacity on a simple proportional basis. As well, the frequent need for taxiing planes to crossover runways imposes further operational restrictions. The Indira Gandhi International Airport in India features three runways; but it has never been considered a model of efficiency.

The efficiency of a three-runway system at CLK, because of its geographical location, would be further constrained by wind shear effects due to the terrain of Phoenix Mountain (Lantau Peak) and conflicts with the arrival circuits of Shenzhen, Macao and Zhuhai airports.

Due to the shortage of flat buildable surfaces, Hong Kong could not have followed the example of cities like Shanghai, Taipei, Singapore and Tokyo, which have retained their older airports after building a new one.  Besides, the concurrent use of Kai Tak and Chek Lap Kok airports would present flight approach issues.

In Hong Kong’s case, a second airport with a “dual-dual” four-runway design can handle 135 -160 million passengers and 12 million tonnes of cargo in a year depending on the chosen runway configuration. In contrast, the current airport could be stretched, in the extreme, to accommodate 74 million passengers and 6 million tonnes of cargo in a year whereas the three-runway scheme could only handle about 100 million passengers and 9 million tonnes of cargo in a year.

From a design point of view, not only can a new airport provide a significantly greater increase in handling capacity, it can also offer expandability beyond 2030 that a third runway at CLK cannot. The new airport can start with a two-runway system and be subsequently expanded to four or even six runways down the road. In contrast, it is practically impossible to add a fourth runway to the existing CLK airport.

The obvious question, then, is: where could a second airport be built?

Location, location, location
A cursory scan of the map suggests one possible location, namely in the waters to the south of Lamma Island. One advantage is the much clearer airspace, making it possible to more flights to come through without having to accommodate nearby airports. The site is also well away from areas that could be developed for housing. A third merit is the area’s relatively lower conservation value compared to northeastern Lantau.

While building a new airport at Southern Lamma will likely take longer than adding a third runway at CLK, demand management techniques, such as peak hour congestion pricing and gate auctioning, can be adopted in the meantime.

Another way to manage demand is by optimizing synergies with Shenzhen Bao’an International Airport, which has much more room for expanding their handling capacity. In this regard, I believe the Government should jumpstart the development of the previously proposed Hong Kong-Shenzhen Western Express Line (Airports Rail Link), connecting the two airports through Qianhai, with a cross-boundary spur line to Hung Shui Kiu. The express link should enable Hong Kong to meet medium term demand while we wait for the completion of the new airport.

Given the limitations of the three-runway configuration and the controversy surrounding the ecological impact of the existing proposal, the idea of building an additional airport to the south of Lamma or elsewhere is well worth a second look.

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Francis Neoton Cheung

Francis Neoton Cheung is the convenor of Doctoral Exchange (, a public policy research collective, and a former member of the Hong Kong Airport Consultative Committee and the Land and Building Advisory Committee.”]