Airports have to get the most out of their assets. But it is not acceptable to declare a runway is longer than it can safely be

Airports have a hard job to do. They have to please airlines, businesses, leisure passengers and people who live close to them. The other thing they have to do is to fit into the local topography.
As well as all the services they hope they can take for granted, airlines want long runways with plenty of unobstructed space around them to allow for mistakes or technical failures that could cause an aircraft to leave the paved surface. Meanwhile, the interests of businesses demand that airports are near them; leisure travellers want airports to be not far from where they live – but not too close either. Local residents make money from the prosperity airports create, but understandably do not appreciate the downside of being nearby. Topography can be distinctly limiting, and roads, rail and suburbs that are built close to the boundary after the airport was constructed can be even more constricting. Engineering can do much to overcome geography and topography, but once homes and civil amenities are in place, it is often politically impossible to arrange to move them.
Osaka Kansai airport is on an island specifically created for it. Hong Kong’s Chek Lap Kok airport is built on reclaimed land next to a natural island, and Macau’s airport – not far away – was created the same way. On a humbler scale, Madeira’s Funchal airport, a single runway clinging to the slopes of the verdant rocky island it serves, a few years ago extended its runway at both ends, taking it yet further out over the sea on concrete piles. It still presents pilots with the prospect of dropping about 15m (50ft) vertically off either end if they get it wrong. But at least the extension means they have a longer runway on which to make mistakes – and, it is to be hoped, get away with them.
Until runway length goes beyond 4,000m between the “piano keys”, which would cope with the demands of almost any transport aircraft built since 1960 even at a hot-and-high location, the question “how long should an ideal runway be?” can only be answered with that standard response to imponderables: “How long is a piece of string?” It is like asking a dyed-in-the-wool traditionalist long-haul pilot how many engines his ideal aircraft would have, and getting the response: “An aeroplane in which the co-pilot can pass me the information, ‘sir, engine number 16 is having problems’,  and I can reply ‘No 16 on which side’?”
Where runways are concerned, the International Federation of Airline Pilots Associations (IFALPA) worries when airports – and airlines – try to get a quart out of a pint pot. A runway needs a declared useable surface area on the basis of which pilots and airline operations departments work out if it is sufficient for the performance of their aircraft. They also need overrun areas – ideally paved – at either end, to cope with mistakes, or with the occurrences – like tyre bursts – that are not included in aircraft performance calculations. IFALPA says the overruns should be at least 300m long. If they are not, the declared useable length – the distance between the thresholds – should be reduced until the overruns are at least 300m. The trouble is that, at some airports, where they either cannot extend the runway length or are not prepared to make the investment to do so, the airports are loath to reduce the useable runway because it would mean that some aircraft at some weights might not be able to take off or land on them. It can be an issue of loss of business as far as airports are concerned. Greed, some would say. Or slightly kinder, but also damning, being prepared to push the safety margins beyond International Civil Aviation Organisation recommended standards.
In this respect the airport operators find they can take refuge in the fact that virtually all long-established airports have at least one runway that does not meet the standards, and in many cases all their runways do not. It is not valid, however, to justify a failing by saying everyone else is guilty of the same sin. IFALPA has used the Air France Airbus A340 overrun at Toronto Pearson to highlight – once again – the issue as a whole, and complaints about Pearson’s inadequacy in particular. As regards this event, in which the aircraft pitched into a ravine 200m beyond the runway end in which people had died in a previous crash, IFALPA is calling for the installation of an arrester bed if Pearson’s operators are not prepared to bridge over the ravine or shorten the notified runway length. And not just at Toronto, but at all airports with comparable limitations. They are right to do so.

Source: Flight International