§ Mr. Speirasked the Minister of Aviation what strength of shock wave per square foot his Department consider permissible for aircraft to cause through breaking the sound barrier whilst flying over the rural parts of Great Britain.
§ Mr. MartenSupersonic flying over the rural parts of Great Britain for research and development purposes is198W rarely permitted at altitudes below 30,000 feet. At this altitude, a Lightning aircraft in level flight would give rise to a shock wave on the ground which would not normally exceed 2 lbs. per sq. ft.
§ Mr. Speirasked the Minister of Aviation what steps are taken by his Department to measure the strength of shock waves on the ground caused by aircraft for which his Department are responsible breaking the sound barrier.
§ Mr. MartenOn numerous occasions over the past three years, instruments have been sited under the flight path of these aircraft so as to measure the strength of the shock waves on the ground and the results of these tests are being studied.
§ Mr. Speirasked the Minister of Aviation what plans he has to authorise aircraft for which his Department are responsible to break the sound barrier during the next 12 weeks; and on how many occasions, and over which counties, this will be happening.
§ Mr. MartenThe number of overland flights which will be carried out during the next 12 weeks is not likely to exceed 75. More than one half of the flights will be over South Wales and its borders (counties: Hereford, Radnor, Brecknock, Cardigan, Monmouth, Carmarthen, Caernarvon and Merioneth), about one-third between Bedford and the Wash (counties: Bedford, Huntingdon, Cambridge, Norfolk, Lincoln) and not more than seven over the Pennines (counties: Yorkshire, Durham, Northumberland, Cumberland) and the Scottish Highlands (counties: Perth, Inverness and Ross and Cromarty) together.