Jet noise over Central Whidbey is loud enough to cause permanent hearing damage, a privately-funded acoustics study asserts.

Jerry G. Lilly, president of Issaquah-based JGL Acoustics, was hired earlier this year by Citizens of the Ebey’s Reserve for a Healthy, Safe and Peaceful Environment to conduct an auditory study on jet operations at the U.S. Navy’s Outlying Field Coupeville.

The study results, which were recently released to the Whidbey News-Times and the Navy, claims noise levels are not only louder than the Navy forecast in a 2005 federally required environmental assessment, but pose a potential health hazard to the community.

“CLEARLY, THE actual 2012 noise levels are much higher than predicted in the 2005 AICUZ study, partly because of the greater number of over-flights, but primarily because of the much higher percentage of nighttime flights,” Lilly wrote.

The 2005 study looked at the airfield and the associated impacts of the Navy’s transition from the EA-6B Prowler to the EA-18G Growler aircraft. It was a required step under the National Environmental Policy Act, or NEPA.

“The maximum sound levels are well above the levels requiring hearing protection and are high enough to potentially result in permanent hearing loss.”

Because of those two facts, the Navy’s 2005 study “should be revised and/or updated to more accurately reflect the potential noise impacts on the people living in the area.”

The Navy did not respond to requests for comment Monday.

A spokesman did ask for a list of questions but it was not returned by press time.

KEN PICKARD, a member of the citizens group’s board of directors, said Lilly’s study cost about $5,000 and provides the first conclusive evidence that information in the 2005 study was inaccurate.

“It said they (the Growler) would be quieter and fly less,” Pickard said. “We’ve proven that’s wrong.”

“People are getting injured and they don’t even know it,” he said.

According to Pickard, the anti-OLF group is hoping to avoid legal action but, if the airfield is not shut down, the noise study may serve as a cornerstone for a potential and future lawsuit.

On June 11, the group’s attorney, David Mann of Seattle-based Gendler & Mann, sent high-ranking Navy officers and Island County’s congressional delegation a letter.

The letter requested “immediate steps” be taken to prepare a new environmental analysis of the Growler and its operations at the airstrip.

THE LETTER was sent to Captain Mike Nortier, commanding officer of Whidbey Island Naval Air Station, Admiral Bill Gortney, Fleet Forces Command, and Rear Admiral Markham Rich, Navy Region Northwest, U.S. Sen. Patty Murray, Sen. Maria Cantwell and Rep. Rick Larsen.

Mann asked the Navy for an answer within 30 days, a deadline of July 12. As of Tuesday, June 24, the Navy had not responded.

Mann’s letter alleges the Navy is obligated under NEPA and its own regulations to conduct a new study, as a “substantial change in a continuing activity” has occurred at the air field.

According to the 2005 study examining the Navy’s transition from the Prowler to the Growler, flight operations at the airfield were expected to decrease by up to 20 percent, from 7,682 in 2003 to an estimated 6,120 in 2013.

“With the decreases in the number of aircraft and personnel associated with replacement of the EA-6B with the EA-18G, the annual number of flight operations is projected to decrease, even though the primary types of mission training and readiness requirement for the (Growler) will remain virtually the same as for the (Prowler),” the 2005 study said.

MANN’S LETTER, however, maintains the reality was the exact opposite. While flight operations did drop to a low of 2,548 in 2008, they have steadily risen to a peak of 9,668 in 2012, according to information provided through a Freedom of Information Act request.

“Significantly, the 2012 numbers are now 158 percent of what was predicted in the 2005 EA for 2013,” Mann wrote. “This clearly demonstrates a ‘substantial change’ in ongoing activities.”

The letter also established an increase in nighttime flights, contrary to the predictions in the 2005 study. It said they would account for only 17 percent of operations in 2013 ­­— about 1,029.

But again, the letter claims approximately 6,184 nighttime flights occurred in 2012.

“This represents a 479 percent increase in nighttime operations from 2003 and a 600 percent increase over what the 2005 EA predicted for 2013,” Mann wrote.

The letter said noise levels from Growlers practicing at the airstrip were determined by Lilly’s study to be significantly, qualitatively different and more severe than what was predicted eight years ago.

Lilly’s study was conducted May 7 and involved readings at five locations, including one inside a home. Both “A-weighted” and “un-weighted” or linear sound pressure levels were recorded.

According to Lilly’s report, A-weighting filters out low frequency noise and is always significantly less than its linear counterpart. Another difference is that A-weighting averages readings over a full second while un-weighted uses the highest reading in one second.

“Most outdoor noise criteria are based on the A-weighted sound pressure level, but some hearing damage criteria are based on the unweighted peak sound pressure level, and that is why the unweighted peak data is included in this report,” Lilly wrote.

Static readings in both forms were consistently above 110 decibels, with a peak of 134.2 in un-weighted at site one — 119.2 in A-weighted. The location is described by Lilly as a “densely populated residential area” one mile south of the southern end of the runway.

The lowest readings were taken inside the home, registering 101.8 decibels in un-weighted and 81.1 in A-weighted. The house is “relatively new” and located less than one mile west of the northern end of the runway.

According to  the Federal Aviation Administration, “unprotected exposure to loud noise (higher than 90dB) for eight or more hours per day for several years, may cause a permanent hearing loss.”

Lilly’s report does account for duration of exposure. At site one, A-weighted exposure over 80 decibels lasted 581 seconds — nearly 10 minutes — but just 11 seconds at 110 decibels or greater.

For unweighted recordings at the same location, time over 100 decibels was 501 seconds and just eight seconds over 130 decibels.

The complex study also examined the impact of increased nighttime operations. Lilly equated one evening flight after 10 p.m. is “exactly equal to 10 identical jet flyovers during daytime hours” due to a reduction in ambient noise and the greater impact on sleeping people.

The 2005 study predicted sound levels near site one at 77 decibels for 2013. Using an average sound exposure level for each jet flyover to calculate the day/night average, Lilly calculated one daytime session and one nighttime session at 79.2 decibels.

Two daytime and two nighttime sessions, however, bumped the average up to 92.6 decibels. Lilly said that is “significantly higher” than the 2005 estimates but speculated it may be because noise levels were predicted based on an annual average that included no-flight days.

“Because jets do not fly every day, when you average the ‘noisy’ days with the ‘quiet’ days the (average day/night) value becomes lower,” he wrote.

According to Michael Monson, a Coupeville resident and member of the citizens group, Lilly’s study was commissioned to provide statistical evidence that would stand up to scrutiny. It was clear from the beginning, he said, that the groups claims had to be backed up with findings from a professional.

“You can’t just say, ‘I took my meter out and took readings,’” Monson said.

To that aim, he and Pickard believe it was money well spent. Monson says that data supports complaints from residents that there is a difference in flight frequency and noise levels.

“We now have facts they can’t dispute,” Monson said.

According to Pickard, the citizens group will not back down. Should the Navy not respond by the July 12 deadline, the organization’s attorneys will file a lawsuit with the U.S. District Court for the Western District of Washington.

“They (the Navy) should deal with this problem,” Pickard said. “It’s not going to go away.”