Rocky Mountain National Park skies are quieter due to new flight paths
May 9, 2013
GRAND LAKE — Rocky Mountain National Park has been working with the Federal Aviation Administration for the past three years to develop new procedures for arriving and departing aircraft to and from Denver. New procedures could reduce aircraft noise in the Park. The new procedures will require pilots to follow a concentrated flight path over the Park and land aircraft in a way that reduces noise and saves fuel.
On an average day, about 600 aircraft fly over the Park on their way to Denver using a major commercial aircraft flight path. The Park and the FAA have developed new procedures that will concentrate the flight paths of arriving aircraft to roughly follow Trail Ridge Road, where there is already human-caused noise. This could mean everywhere else in the park could be quieter this summer.
Before these new regulations, pilots were required to fly over a designated point outside of Estes park, called an arrival gate, which meant a lot of planes over Estes Park and the Park. The pilots would then deploy speed brakes or spoilers on the wings of their aircraft to slow crafts to the proper airspeed, creating more noise.
The new flight paths take advantage of satellite based navigation technology and computerized Flight Management Systems onboard most commercial aircraft. Using the new procedures, pilots will fly more narrowly defined arrival and departure routes, and the aircraft will descend to the runway on a smooth profile with throttles at idle.
Pilots used to utilize, at the direction of air traffic controllers, a stair-step descent profile to reach the runway. This would require pilots to apply throttle each time the aircraft leveled off, which created more noise. The new procedure, which doesn't require pilots to repeatedly throttle the aircraft, cuts noise as well as saves fuel.
The two new procedures went into effect on Dec. 3, 2012, and are now being used by most of the commercial airlines. If all of the new procedures impact the Park as planned, Park-goers could experience a much quieter experience.
The Natural Sounds and Night Skies Division of the National park Service deployed sound monitoring equipment in the park from mid-November to mid-January to record aircraft overflight noise before and after the new procedures went into effect. The division is analyzing the data to determine how aircraft noise has changed.