AS a working Hong Kong airline pilot I would like to add to your reports on the Singapore Airlines air miss and the Dragonair go-rounds (South China Morning Post, May 6). On the air miss, it would surprise you to know how little of the world's airspace is covered by civilian radar, particularly over water and Third World areas. Radar helps to prevent collisions. Its coverage could be global but is not because of the cost. The industry is trying to solve this problem with the introduction of the Terminal Collision and Avoidance System (TCAS) which is an airborne radar that ''sees'' another aircraft, or ''conflict'', and tells the pilot how to miss it. The latest aircraft come with TCAS but older aircraft must be refitted with it by law, and that takes time and money. Good communication also helps to prevent collisions, but in many parts of the world primitive radio is the only form of communication. You can talk via satellites but it is very costly. Perhaps a co-ordinated surcharge on every ticket for these improvements might make them happen a bit quicker. As for the Dragonair go-round at Kai Tak. A go-round or missed approach, or overshoot if you're English, is a very normal procedure. It's an airborne take-off, if you like, without all that tedious trundling along the runway. I started to go bald the day I was in a plane on London Gatwick's runway and another aircraft didn't go round when it should have, scraped over the top of us and landed. Now that was scary! P.R. BISSELL New Territories
