New airport takes enlightened approach to landing systems

(HONG KONG, 3 September 1997) -- Pilots will find landing at the new airport at Chek Lap Kok an illuminating experience thanks to one of the world's best runway and taxiway lighting systems.

Touching down at the new airport will be very much a pilot's idea of a perfect landing -- mainly because pilots and air traffic controllers helped AA engineers to design the system.

The new airport's landing systems will make a major contribution to maintaining Hong Kong's role as a centre of international and regional aviation. These systems will allow Chek Lap Kok's two 24-hour runways to operate in some of the worst weather likely to affect Hong Kong. In contrast, the current international airport at Kai Tak has a single runway that cannot always operate in poor weather, and is subject to night closures.

Airport runways around the world have designated ratings for the aircraft landing operations known as Precision Approach Categories. These inform the pilots at what minimum visibility the runway system can support a safe landing. Chek Lap Kok's southern runway is Category II, meaning pilots may land as long as they can see at least 350 metres along the runway from a height of 30 metres. The northern runway will have a higher Category IIIA rating, which allows pilots to land in only 200-metre visibility.

At Chek Lap Kok, pilots making their landings will first see the runway approach strobe lights, which pulsate in sequence leading the pilot towards the runway as the aircraft nears touchdown. Centreline lights and Precision Approach Path Indicators on either side of the runway will guide pilots to the touchdown zone.

Edge lights will help keep the aircraft on course. Pilots will also have plenty of warning before they reach the end of the runway, with lights changing from all white to a combination of red and white, then finally to all red. Apart from providing visual landing aids, the airfield lighting allows the safe and efficient taxiing of aircraft about the airfield. Central to this is the Surface Movement Guidance and Control System (SMGCS), a sophisticated set of automated controls and monitoring devices that are especially useful under low visibility conditions. Green centreline lights will guide the aircraft from the runways to the taxiways and then to the passenger terminal apron parking areas.

Aircraft movements on to runways ahead of takeoff will be controlled by stopbars, a series of red lights running the width of the taxiway pavement. Even in the poorest visibility, pilots will be aware of their exact location on the airfield and when and where to proceed. Should an aircraft cross the stopbars before it is safe to do so, alarms will be set off in the Air Traffic Control Tower.

"We will be setting the pace for designing intelligent, user friendly systems that are ideal for low visibility conditions," said AA Senior Design Engineer Ravi Trivedi. "Our control systems are designed to the highest standards through a collaborative effort between the International Federation of Air Line Pilots Associations (IFALPA), Civil Aviation Department safety officers and air traffic controllers, and the AA. Even guidance signs on the airfield have been designed to new improved International Civil Aviation Organisation (ICAO) standards."

In keeping with the AA environmental management policies, the 8,000 lights employed along the runways and throughout the airfield will be more energy efficient than the traditional lighting.

"Although they are smaller than standard lights, they are more efficient by creating greater illumination with less power," Mr Trivedi said. "It will also be a more reliable system, with dual emergency power generator systems for back-up. In fact, as an added safety feature, the generators will become the primary source of power in bad weather conditions."

Thorn Lighting (CLK) Ltd was awarded the ground lighting contracts for both runways.

Their combined value is HK$368.2 million (US$47.2m).

Ref. PR-301