§ 74. Mr. Onslowasked the President of the Board of Trade what aircraft currently operating out of London, Heathrow, Airport, are capable, when making a normal take-off with a 75 per cent. of capacity load, of keeping below a noise level of 90 perceived noise decibels.
§ Mr. J. P. W. MallalieuNone at takeoff and, as regards aircraft used on scheduled air services, none even at four statute miles from start of roll after power cutback.
§ 75. Mr. Onslowasked the President of the Board of Trade what proportion of the infringements of permitted takeoff noise levels at London, Heathrow, Airport during 1967 were due to operational safety factors.
§ Mr. J. P. W. MallalieuThis figure is not readily available. However, three-quarters of the infringements were in respect of take-offs on the runways where the monitoring points are closest and in conditions when it would be reasonable for the pilot to exercise his absolute discretion to override noise abatement330W requirements to provide a satisfactory safety margin.