HC Deb 20 January 1970 vol 794 c108W
Mr. Leslie Huckfield

asked the President of the Board of Trade what percentage of aircraft using London Airport is fitted with secondary radar equipment.

Mr. Goronwy Roberts

Secondary radar is required for flight at or above flight level 250 (approximately 25,000 feet) over the United Kingdom and in some parts of Europe. Transport aircraft using London (Heathrow) Airport and flying at these levels must be so equipped, but I do not have the information necessary to express their numbers as a percentage.