Noise impact upon helicopter pilots and helicopter ground crews

Status:

completed 01/2001

Aims:

Helicopter pilots, auxiliary personnel and ground crews are subjected to noise hazards at their workplaces. For prevention purposes, the level of actual noise impact at the workplaces must be measured, and its origin identified. In some fields of helicopter deployment, considerable use is made of headsets for radio communications. In certain cases, pilots simultaneously monitor not only several radio channels, but also a number of radio beacon channels for orientation purposes. The total noise impact upon the pilot can be measured directly only by means of an ear microphone. Flight safety issues prevent such microphones from being used, however. The objective of the project is to ascertain noise impact values from which the assessment level for employees can reliably be calculated. The assessment level is a measure of the affect of a noise upon human hearing. It represents the level of a constant noise over a period of eight hours, or the equivalent level. Limit values for the assessment level can be found in the applicable statutory provisions.

Activities/Methods:

As ear microphones cannot be used directly for measurement of the noise impact upon pilots, a new measurement method had to be developed. The component of noise exposure caused by radio communication was to be measured separately from the exposure to noise in the cockpit. The sound level in the cockpit is measured by means of sound level meters. The dosimeter measurement technique developed by the BIA (BG institute for occupational safety) projects concerning noise impact at construction site workplaces was also used here for some measurements. Where possible, statistically validated mean values and standard deviations for the noise impact were to be measured for employees for specific occupational groups, areas of deployment, or helicopter categories.

Results:

The helicopter type was shown to have the greatest influence upon the noise impact upon the pilot. Classification by activity or occupational group (e.g. pipeline survey flights, crop work, personnel transport) is not necessary. The level of radio communication, where applicable, also had a considerable bearing upon the pilot's noise exposure. Case-by-case measurements are recommended for precise measurement of the noise exposure. Where performance of measurements is not possible, measured noise impact values obtained for comparable helicopter types and activities (for example from the present project) may be used, consideration being given to the associated uncertainty. The noise exposure of the auxiliary personnel and ground crews studied in the project was influenced essentially by the time spent by these personnel in the proximity of the helicopter with the engine running, and their distance from it.

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