I refer to the letter from Edwin McAuley headlined, 'Still worried about windshear', which appeared in the South China Morning Post, on July 8. My responses to his questions are as follows: The consultancy studies undertaken prior to the selection of Chek Lap Kok as the site for our new airport suggested that the level of windshear there and that at Kai Tak were comparable. However, the comparison was based on wind tunnel experiments only. Since the opening of Chek Lap Kok, as the experience gained so far is still limited, it would be difficult to have a meaningful comparison with Kai Tak or other major airports.
In addition to Dragonair and Cathay Pacific, there are more than 60 airlines from 37 different countries operating regularly into Chek Lap Kok. As on-board windshear warning system equipment is not mandatory under international rules, we are not in a position to state which airlines have their aircraft fitted with such equipment.
In my letter to these columns on June 24, I did state that the decision on whether to continue an approach in potential windshear conditions lies with the pilot but not air traffic control, as the pilot would be in the best position to make the judgment.
Under such a scenario, up-to-date weather conditions, including windshear and turbulence warnings, are provided by the tower controller to pilots. Based on the instantaneous weather reports, the pilots make comparisons with their operating criteria.
If the conditions are worse than the company operating minima, the pilot will not commence an approach, or, if already on the approach, will abandon the landing immediately.
On the day in question, only a small number of aircraft diverted during the passage of Typhoon Maggie (two only) as compared with the large number (more than 200) which landed safely.
