On the heels of a U.S. District Court critique of the Navy’s environmental review for increasing its EA-18G jet fleet and related flight operations at Naval Air Station Whidbey Island, the Navy has released a noise monitoring report that was requested by Congress.
Congress required the Navy to study real-time aircraft noise at two West Coast bases.
The Navy studied the increasingly contentious Whidbey Island base, as well as a base in California.
At NAS Whidbey Island, the subject of noise from the EA-18G jets, called Growlers, has been a hot-button issue as the Navy has sought to expand the Growler fleet.
The issue wound up in court after the Navy published an environmental impact statement (EIS) in 2019 claiming its jet operations, even with an increase from 82 to 118 Growlers, pose no significant harm to Whidbey Island and surrounding areas.
The Navy’s noise monitoring report that is dated Nov. 30 concludes that the modeling it used to predict the impact of aircraft noise, such as for the EIS for NAS Whidbey Island, is accurate.
In fact, according to the report, monitoring data shows jet operations often create less of an impact than modeling suggested.
“Overall, the Navy determined that the ... noise models operate as intended and provide an accurate prediction of noise exposure levels from aircraft operations for use in impact assessments and long-term land use planning,” the report states.
Around NAS Whidbey Island, the Navy collected real-time, 24-hour noise level data at 11 sites over four seven-day periods in December 2020 and March, April, June and August 2021.
During those 28 days, 7,377 hours of data was collected, according to the report. Also during the 28 days, a reported 7,579 jet operations took place.
Any time an aircraft touched or left a runway surface was counted as one operation, according to the report. That means each field carrier landing practice loop, during which pilots practice landing and taking off as if from an aircraft carrier, counted as two operations.
According to the report, one site west of NAS Whidbey Island’s Outlying Field Coupeville and one site near Port Townsend City Hall saw average noise levels higher than previously modeled. The other nine sites saw levels lower than previously modeled.
At the California base, Naval Air Station Lemoore, all 10 sites studied saw average noise levels lower than previously modeled.
“The Navy compared the ... modeled results to the real-time measured data for the airfields at both installations and determined that the noise model operates as intended and provides an accurate prediction of levels from aircraft operations,” the report states.
The Navy also found that NAS Whidbey Island operations appear to have no significant impact on nearby Olympic National Park, based on 365 days of data collected near the Hoh Rain Forest Visitor Center.
“The resulting aircraft levels are not a significant contributor to the levels at the meter location,” the report states.
The Navy used noise monitoring guidance from the American National Standards Institute-Acoustical Society of America for the study and collected data for the project during periods of high, medium and low flight activity.