Grand Canyon Releases Aircraft Noise Study

The National Park Service at Grand Canyon has released a report titled, Aircraft Noise Model Validation Study, dated January 2003. The report completes a study to determine which of four computer models best calculates tour aircraft audibility in the Grand Canyon. The results of the study are important because computer models are the only practical means to assess progress in meeting the requirements of Public Law 100-91 to substantially restore natural quiet at Grand Canyon National Park. Audibility is the measurement used to define substantial restoration of natural quiet. The report was prepared by Harris Miller Miller & Hanson Inc., a leading acoustics consulting firm, for the National Park Service.

In the report, which can be found on the park's website at, and its attached appendices, the reader will find a detailed step-by-step description of all methods, data, and results of the study. This is a highly technical scientific report prepared by experts primarily for experts. Readers are strongly encouraged to start with the Executive Summary and Study Summary at the beginning of the report.

As detailed in the report, the study methodology was developed by consultant firms with comments, advice, and review by staff from federal agencies and a team of recognized experts in acoustics, statistics and scientific methods. In the Acknowledgements section, however, the authors carefully point out that the final interpretations and words in the report are those of the authors, Harris Miller Miller & Hanson Inc., and not those of any of the other study participants.

For additional information regarding this report, please contact Dr. Kenneth Weber, Grand Canyon Science Center, at (928) 638-7753 or Maureen Oltrogge, Public Affairs Officer, at (928) 638-7779.

Maureen Oltrogge
Public Affairs Officer
Grand Canyon National Park
(928) 638-7779