Checkerboard Approach - Was it too Dangerous?

Have you ever flown into Hong Kong before 1998? If so, you probably never forgot your arrival. Before the current airport in Hong Kong took over in 1998, Hong Kong’s Kai Tak airport was the main airport for all arriving and departing aircraft. The airport had a runway of over 10 000 feet so it was perfectly capable to handling large long haul aircraft, although, large aircraft had a rather hard time getting down to the runway.

If you’ve been on an airplane before you probably know how the whole jig works. There is a system called an instrument landing system (ILS) which includes a VOR beacon and a glideslope. When the pilot turns his aircraft to face the runway, he captures the ILS signals and the aircraft flies itself down to the runway, until the pilot decides to take over manual control by disengaging the autopilot. This is a standard procedure at major airports all around the world, although, at some specialty airports, this procedure does not exist. The absence of an ILS system usually means that one cannot be physically implemented into the airport because of surrounding terrain. That was the case at Hong Kong’s Kai Tak airport.

Hong Kong’s downtown core was basically built around Kai Tak. Eventually, the entire airport was surrounded by high rise office buildings and residential areas. This doesn’t pose as much of a problem as the mountain does. Kai Tak had two runways, runway 13 and runway 31. You may be confused if you look at a diagram of the airport because there only seems to be one runway. Runways 13 and 31 are the same runway, but runway 13 is on one end and runway 31 is on the other. Runway 13’s straight in approach is obstructed by mountains which makes landing on this runway very difficult. One may say “why not land on the other runway?”, but this is usually impossible because departing aircraft cannot take off towards the mountains so aircraft must both land and take off on runway 13.

So, in the 1970’s one man came up with a radical idea. He suggested that an ILS system could be implemented for aid the pilots on approach into the airport, but not line them up with the runway. The system worked as follows. The pilot would capture an ILS signal which would points directly at the mountain. Then, the pilot would disconnect the autopilot when he sees a brightly lit checkerboard and make a 47 degree right turn to line up with the runway. Oh, I forgot to mention that the winds on the airfield were usually a right crosswind making it even more difficult for the pilot to line his plane up with the runway.

So, now that we all know about the “checkerboard approach”, it’s time to ask the question, was it too dangerous? The topic has been debated for a while but the main answer is no. The approach was in no way dangerous. It was a complicated approach in which pilots had to spend hours training in the simulator, but it was not dangerous.

In fact there was only one accident concerning the approach, which was a plane overshooting the runway and ending up in the ocean. If there wasn’t more than one accident, it says to me that the approach could not have been dangerous. If this was back in the 50’s, I may have said it was dangerous for one reason. Flight Simulation has reached new heights in the past 50 years and now every pilot must train in sophisticated simulators before they even get to touch the real aircraft. Since the simulator technology existed when the approach was made, pilots got the hands on experience of the flying the approach realistically before they even tried their hand at the real thing.

In addition, many people think that the airport was closed mainly because the approach was too dangerous but this is not the case. Kai Tak airport was old and very small. There was simply too much traffic in such a small airport so they had to build a larger airport on a manmade island. No approach is dangerous, as long as the pilots have the proper training to make the approach safely. One cannot fly into Kai Tak anymore since its closure in 1998, but the checkerboard approach will always be remembered as the beast for pilots to tame.