Analyses of quiet technology seasonal relief incentives for Grand Canyon National Park: Combined annual reports for 2015–2018

Rapoza, Amanda; Joyce, Damon; Ward, Vicki; Lee, Cynthia

doi:10.36967/nrr-2292977

This report describes the legislative background, modeling process, and annual results used by the National Park Service (NPS) and the Federal Aviation Administration (FAA) in order to meet the requirements of the National Parks Overflights Act of 1987 (Public Law 100-91), the National Parks Air Tour Management Act of 2000 (NPATMA, Public Law 106-181) and the Moving Ahead for Progress in the 21st Century Act of 2012 (MAP-21, Public Law 112-141) regarding the substantial restoration of natural quiet at Grand Canyon National Park. MAP-21 requires all commercial air tour aircraft operating within the Grand Canyon National Park Special Flight Rules Area convert to quiet aircraft technology (QT) within 15 years (i.e., by 2027). MAP-21 also requires the FAA and NPS to provide incentives for commercial air tour operators that convert to QT prior to the statutory mandate. Pursuant to NPATMA, the cumulative impact of providing incentives, such as increasing flight allocations for QT, must not increase noise at Grand Canyon and must not diminish the achievement of substantial restoration of natural quiet that was called for in the Overflights Act. On January 1, 2015, the agencies implemented a QT incentive for commercial air tour operators consistent with both MAP-21 and NPATMA. The incentive provides seasonal relief during the first quarter (January–March) from allocations for commercial air tour operators that utilized QT aircraft in the popular Dragon and Zuni Point corridors. During the first quarter, QT air tours did not need to use an allocation, while non-quiet technology air tours still required the use of an allocation. The allocations that operators would have been required to use during the first quarter (“saved” allocations) can then be flown within the corridors during other times of the year. The NPS and FAA developed a methodology to ensure the incentive complies with the statutory mandates for not increasing noise at Grand Canyon and not diminishing the achievement of substantial restoration of natural quiet. Beginning in 2015, the agencies have modeled each year’s commercial tours flown in the Dragon and Zuni Point corridors. This report summarizes the annual air tour reporting data, use of QT, and results of the modeling for cumulative noise and substantial restoration of natural quiet for years 2015–2018. Key results include: ● Quiet technology incentives appear to increase QT usage during the seasonal relief period—the first quarter of the year. Quiet technology usage is greatest in the first quarter, averaging 86%, and then drops in the second through fourth quarters. Quiet technology usage is lowest in the third quarter when total flights are highest. ● Modeled annual noise exposure through 2018 has not exceeded the 2012 baseline level. However, the annual noise exposure has closely approached the baseline level. The substantial restoration of natural quiet has not been diminished. The area of the park free of noise for 75% of the day has not dropped below 50%. During days of peak activity, the percentage of park area free of noise for 75% of the day has ranged from 62–67%. The NPS and FAA will continue annual evaluation of seasonal relief incentives through modeling of annual noise exposure in the Dragon and Zuni Point corridors, as well as the achievement of substantial restoration of natural quiet through modeling of audibility duration throughout the park.