§ 27. Mr. Barnesasked the President of the Board of Trade what proportion of aircraft approaching London Airport in a westerly direction, during the latest 12-month period for which figures are available, were instructed by Air Traffic Control to join the three degree glide slope at a distance from touchdown which necessitated them flying over Chiswick at a height of between 1,500 and 2,000 feet.
§ Mr. Goronwy RobertsAircraft joining the glide path before passing over Chiswick are required not to descend below 2,000 ft. until established on it. This general rule would be varied by Air Traffic Control only exceptionally when necessary to maintain height separation, and no count is kept of such occurrences.
§ Mr. BarnesWhy has the impression been given in the past that no aircraft join the glide slope at a height of less than 2,000 ft? It now becomes clear from correspondence which a constituent of mine has had with the Board of Trade 1189 that during busy periods aircraft fly over Chiswick at 1,500 ft. before joining the glide slope? Surely it is the number of times that this happens that needs to be monitored rather than an adherence to the three degree glide slope.
§ Mr. RobertsThe monitoring takes within it that section of operations. My hon. Friend has in part answered his own question—that separation of aircraft is necessary at peak periods. This is when these exceptional departures from the general rule take place.
§ 31. Mr. Corfieldasked the President of the Board of Trade whether he is satisfied that landing aids appropriate to the Boeing 747 are now available at Heathrow Airport; and if he will make a statement.
§ Mr. Goronwy RobertsYes, Sir. Boeing 747 aircraft use the internationally-approved automatic landing system and this is already installed at Heathrow. Some modification may prove necessary to the visual approach slope indicator near the runway threshold, depending on the outcome of current discussions within the International Civil Aviation Organisation.
§ Mr. CorfieldDoes that mean that currently the 747 cannot land under precisely the same conditions as other aircraft now in operation? To what extent are the traffic arrangements affected by the alleged increase in turbulence of the 747 on separation?
§ Mr. RobertsThere is another Question dealing with turbulence. Turbulence affects the position only minimally. Boeing 747 aircraft have already landed without difficulty. Some automatic landings have already been made. The question of visual installation is now being examined. There may need to be an international agreement to change some of the arrangements.