FlightGlobal.com
Home
Premium
Archive
Video
Images
Forum
Atlas
Blogs
Jobs
Shop
RSS
Email Newsletters
You are in:
Home
Aviation History
1954
1954 - 1083.PDF
FLIGHT, 16 April 1954 485 With WIC. R. f. Bulstrode (in duffle coat), London Airport's air traffic controller-in-charge, are pictured a representative G.C.A. team (left to right): Mr. B. E. J. Heard, final controller; Miss D. R. Colter, tracker; Mr. E. C. Mather, supervisor; Mr. G. H. Bayes, director; and Mr. P. D. Borcherds, director. azimuth and elevation information for the final part of the approach (see adjacent diagram). Our visit was made in perfect G.CA. weather, with eight- eighths cloud at 600ft and visual range for the runway in use (10R) of 1,200 yd. In quick succession, a B.E.A. Elizabethan, a Swissair Convair and an Air France DC-4 made flawless approaches. In each case the work of the G.C.A. team began with identification of the aircraft over Epsom by No. 1 Traffic Director, using the search radar. The aircraft was then transferred to No. 2 Traffic Director, also using search radar, whose job was to line up the aircraft for talk-down approach from a range of eight nautical miles. The Talk-down Controller, assisted by the Tracker, then took over, both using the precision radar. The Traffic Director issues instructions to the pilot but the Talk-down Controller does so only if the aircraft is making a full G.C.A.: when die pilot elects to make an I.L.S. approach and asks for monitoring by G.C.A. the Talk-down Controller gives information only. Certain precision systems provide the Talk-down Controller with both azimuth and elevation ("azel") scopes showing the movement of the air craft in relation to, respectively, the centre-line of the runway and the specified glide-path. Equipment used at London Airport, however, provides the Controller with azimuth scopes only. The elevation scope is watched by the Tracker, who uses a combined manual and electronic computing system to give the Controller a simpli fied picture of the aircraft position in relation to the glide- path. This takes the form of a needle (representing the aircraft) which moves on a scale graduated in tens of feet above or below the glide-path. The Tracker also notes the distance of the aircraft from touch-down, which he (or she) calls out to the Controller for transmission to the pilot. Two azimuth scopes are used by the Controller—one long- range screen covering eight nautical miles with concentric rings at two-mile intervals, the other a short-range screen with four half-mile graduations. The short-range display is almost as informative as a television screen, providing a clear indication of the Calvert cross-bar lights, the runway threshold and the runway itself. To prevent misinterpretations by the pilot, transmissions by the Traffic Director and Controller conform very closely to a pre-determined "patter". An idea of the procedure is given by these typical extracts: — Traffic Directors (1 and 2): "Able King—you are identified . .. you are cleared to leave Epsom . . . heading 280 . . . descend to 2,500ft... turn right... heading 300 ... you are five miles south west of London on downwind leg . . . continue descent to 1,500ft . . . QFE touch-down is 1010 . . ." Talk-down Controller: "Able King—this is London talk-down . . . How do you read me? Over . . . Roger, do not acknowledge any further instructions . . . your heading is good, you are six miles from touch-down . . . begin your descent now at 500ft/min . . . check your wheels down and locked . . . your heading of 105 is good, very steady on the glide path . . . turn left left three degrees . . . you are two miles from touch-down, heading good, on the centre-line, on the glide-path . . . 400 yards from touch down . . . talk-down completed." R.B. (Below) Mobile operations room at London Airport. In the background, a B.O.A.C. Argonaut has just "unstuck" from Runway 10R. L'lr ill'
Sign up to
Flight Digital Magazine
Flight Print Magazine
Airline Business Magazine
E-newsletters
RSS
Events
