Intense concentration is the name of the game for the team of air traffic controllers on duty at Chek Lap Kok
Nothing provides a more vivid illustration of Hong Kong's claim to be a city that never sleeps than the airside operations zone at Chek Lap Kok. Long after midnight intercontinental passenger flights await clearance for takeoff, cargo-laden freighters hurtle down the runways and private jets whisk late-departing celebrities or business tycoons off on another overseas jaunt.
Even between 3am and 4am there can be 10 to 15 movements an hour and, as dawn approaches, the pace really starts to pick up. From 5am onwards the first of the day's scheduled long-haul arrivals are making their final approaches and, soon after, early-bird shuttles and regional short-hauls are beginning to taxi out, ready for departure.
It is a scene of near-constant activity and, of course, one which requires expert monitoring and precise choreography. And two nights out of every 10, as dictated by his department's standard roster, responsibility for that falls to Carl Modder. A senior air traffic control officer with the Civil Aviation Department and, more specifically, aerodrome supervisor at Hong Kong International Airport, Mr Modder has reached a point where the routines associated with the overnight shift have become almost second nature. He was quick to emphasise though that, day or night, the job itself is never less than demanding.
It takes intense concentration and a sense of calm authority to oversee the movements on two runways, while remaining fully aware of the weather, changing schedules and the overall traffic situation. Climbing to the control tower therefore means entering a high-pressure work environment, where every decision is important and every instruction has to be clear and concise. Specifically for the night shift, Mr Modder explained, there are 16 controllers on duty, fewer than the 36 for mornings and 32 for afternoons in view of the comparative traffic volumes.
They are divided into specialised teams. Those in the tower supervise take-offs and landings on the two runways, monitoring each flight on screen and by line of sight. The others are on approach control and short-range radar, or area control and long-range radar. Taken together, this covers the full extent of Hong Kong's airspace up to the northern boundary with the mainland and about 360km towards the neighbouring sectors overseen by Taipei, Manila and Sanya.
'Whenever we have a flight going in or out we communicate with the respective control centres to pass information about its altitude, the time and position it will enter or leave a sector, and to give a code for identification,' Mr Modder said. 'All the communication is done in English, and it's not just for arrivals and departures. There are also a lot of flights not landing at Chek Lap Kok, but which overfly our airspace at higher altitudes.'
He said that, normally, by one in the morning, there is a halt in passenger flights because of airline scheduling. For the next few hours, the control tower therefore handles mostly long-haul freighters. These are generally heavier than passenger flights and, as a result, use a greater amount of runway and have different landing speeds.
'Most aircraft that operate in Hong Kong are larger [types] and all should be able to follow a certain speed that we assign,' he said.
Though the overall workload at night was obviously less than at other points in the 24-hour cycle Mr Modder noted that a controller could still be 'working' several aircraft at the same time. To ensure the necessary levels of wakefulness and concentration it was therefore usual to have at least a 30-minute break after each two-hour period on duty. Some individuals might read the paper or check their e-mail as a way of relaxing, while others preferred to just have a wander around.
'One problem if you want a bite to eat in the middle of the night is that there's no canteen and the restaurants in the terminal are all closed, so a lot of staff bring in cookies and fruit,' Mr Modder said. 'Some drink coffee but, since controllers sit side by side, we tend to talk, co-ordinate and keep each other up, so there is no risk of nodding off.'
He acknowledged that when starting the job adjusting to the shift pattern could be difficult. 'You are fighting against your circadian rhythm and biological clock but, as you go on, you get used to it,' he said, adding that most people who joined the department stayed. 'I have found that the main thing is to have adequate rest before you come to work and to make sure you are fit because the two consecutive nights can be quite stressful.'
His own routine, honed in the course of a 30-year career in air traffic control, includes taking a 60- to 90-minute nap each afternoon before a night on duty. Afterwards he is usually back home in Tsim Sha Tsui by 9am, has breakfast, sleeps for a few hours and is then ready to 'kick on'. In his younger days that often meant heading to the beach but, more recently, it has been to play hockey or badminton as a way of keeping in shape and being sure to pass a stringent annual medical.
Over the years there were inevitably other areas of adjustment. In particular those concerned how to spend more time with his two sons, aged 23 and 21, and his wife, a senior air traffic flight service officer usually working from nine to five.
'Of course working shifts affects your family and social life,' Mr Modder said. 'For instance if you are sleeping odd hours you have to make allowances to see your kids and have meals with them or tend to their schooling needs.
'You won't always have the luxury of talking to them at night or you may be leaving home as they come in. It can be difficult but each of us learned to make accommodations in this regard and you just have to adjust your life accordingly,' he said.
He added that being able to attend weddings or other social occasions was simply a matter of good forward planning. If such events couldn't be arranged for a regular day off there was always the possibility of a shift swap, and the sense of fraternity among controllers meant they would always try to accommodate each other.
'We produce a monthly roster so all the controllers know which position and shift pattern they will have by the middle of the previous month,' Mr Modder said.
Dispensation from night duty was rare and only considered if a current employee developed a genuine medical problem. In such cases they might be assigned to administrative or office duties, or join the training unit as an instructor.
'The job description that we advertise already states that the role of an ATC involves shift work, so from day one an applicant is already aware what is required,' Mr Modder said. 'It is something you have to do, like it or not.'
This is the first in our eight-part series on people who work at night
Hours of duty
The standard shift pattern for air traffic controllers at Chek Lap Kok is based on the following 10-day cycle:
Days 1 and 2 afternoon shift from 2.45pm to 10pm
Day 3 off duty
Days 4 and 5 morning shift from 7.45am to 3pm
Days 6 and 7 overnight shift from 9.45pm to 8am
Day 8 recovery/sleeping day
Days 9 and 10 off duty
In the course of a typical night shift, the team in the control tower might handle from 90 to 105 arriving flights and close to 90 departures