Low-Flying Military Aircraft: Noise Study (Hansard, 20 February 1997)

Earl Howe

The study, commissioned with the Institute of Sound and Vibration Research of the University of Southampton, as prime contractor, supported by the National Physical Laboratory and the Medical Research Council, was completed in December 1996. Because of the wide dispersion of military low flying, and the infrequency of exposure to noise from this source by the average person, the study concluded that it would not be practicable to carry out a meaningful epidemiological study of the effects of noise from low flying military aircraft on the health of overflown populations. Statistical calculations suggested that an initial sample of at least 20,000 people would need to be included in any study population; however, in order to allow for confounding factors and uncertainties in the pattern of exposure, the size of the study population would have to be increased by a factor of between five and 10.

A comprehensive field validation study carried out in the Vale of Evesham found that the daily noise exposure in the most heavily over flown areas did not exceed that experienced by over a quarter of the population of England and Wales from general ambient noise. No individual aircraft event exceeded 120db(A)_Lamax and the majority of events were below 100db(A). This reaffirms our belief that, although the 70WA restrictions placed on the heights, speeds and operating procedures of military aircraft are designed to ensure that noise levels on the ground do not exceed 125db(A), a level which research suggests provides a margin of safety to human hearing, in practice any exposure to noise from military low flying is likely to be significantly lower.

Copies of a composite document comprising reports of ISVR and the MRC, and an executive summary by the tri-national steering committee have been placed in the Library of the House.

My department will continue to be involved in scientific research on noise and health. Should new research suggest a linkage between military low flying and adverse health effects, we will consider what changes to our aircraft operating procedures should be made. In the meantime, we firmly believe that they reflect the best available scientific and medical advice.