A new Marine Corps study says airfield use at Kaneohe Bay is expected to increase 49 percent by 2018 compared with a 2009 "base-line" level of activity, as the Corps and Navy update aging aircraft and add new capability in a reflection of Hawaii’s growing importance in the Pacific.

Plans call for basing 18 P-8A Poseidon submarine-hunting jets at Kaneohe Bay, 24 MV-22 tilt-rotor Ospreys, 18 AH-1 Cobra and later, Viper, attack helicopters, and nine UH-1 Huey transports.

The 652-page draft environmental impact statement released by the Marines for the helicopters and Ospreys also points to a 200 percent increase in "transient" large jet operations by aircraft such as Air Force C-5 cargo carriers and Russian/Ukrainian An-124s, the world’s largest cargo airplane, as logistical needs grow.

The increases would be offset by the retirement of two squadrons of about 24 aging CH-53D Sea Stallion helicopters (one squadron of CH-53E Super Stallions would remain) and the departure of most of the Navy’s propeller-driven P-3C Orion sub hunters.

Plans for so many aircraft plying the skies near their neighborhoods have some Kaneohe residents worried even more about the noise that has been a constant and sometimes unwelcome companion along the emerald bay.

"It’s absolutely ridiculous," said Kaneohe resident Guy Ballou. "The noise is going to increase so much here that the quality of life is going to go down incredibly."

The Navy previously said the basing of 18 P-8As, a military version of the Boeing 737, would bring slightly more noise.

Similarly, the Marine Corps said in its draft environmental report that the operation of tilt-rotor Ospreys and attack and transport helicopters out of Kaneohe Bay would mean "minimal" increases in noise.

"Fixed-wing aircraft would continue to be the dominant contributor to the overall aircraft noise environment," the report states.

The study does not measure noise levels for individual flights, however. Instead, it averages out sound by 24-hour day/night periods that indicate the greatest noise increase — three decibels — at Kealohi Point.

Daniel Siangco, a Kaneohe Neighborhood Board member who lives across the bay from the Marine Corps base, said he hasn’t received much feedback from residents about the aircraft basing plan.

"At times it (aircraft noise) can be annoying," Siangco said, "but I’ve been there almost 22 years and I believe that we need to have that type of safety and protection here in the islands. … They’ve been pretty good about (the noise). It’s not like they’ve been doing it early in the morning or late at night."

The helicopters and Ospreys are smaller and quieter than transient fighters such as the F-18 Hornet and cargo carriers including the Air Force’s C-17s, officials said.

Between 2012 and 2018 the helicopter and Osprey basing would bring about 1,000 active-duty personnel and 1,106 dependents to Kaneohe Bay, which had 9,872 Marines and dependents living on base in 2010, according to the study.

The Marines’ preferred plan for the helicopter and Osprey basing is paired with $578 million in anticipated construction costs to demolish old barracks and build three new four-story buildings, construct two hangars and a new headquarters, renovate and expand existing facilities, and create an additional reinforced concrete landing pad at West Field over six to 10 years.

The helicopters would be the first to start arriving, as soon as next fall, with five Cobras and four Hueys.

Officials said in May the first P-8A Poseidons would come to Hawaii in 2015, and the basing plan has one squadron of 12 Ospreys showing up in 2014 and the second in 2015.

The draft EIS, available at www.mcbh.usmc.mil/mv22h1eis, has a 45-day public comment period, and public meetings will be held on Oahu and Hawaii island from Nov. 30 to Dec. 8.

According to the study, the Marine Corps organizes operations around Marine Air-Ground Task Forces; units must "train as they fight" with all components, including helicopters; and the 3rd Regiment at Kaneohe Bay is the only infantry regiment in the Corps that does not routinely train with rotary-wing light-lift and attack support.

The helicopter and Osprey basing is "part of the Marine Corps’ plan to restructure and rebase its forces in the Pacific over the next 10 years," the report said.

Flight training would take place not only at Kaneohe Bay, but also at Bellows, Schofield Barracks East Range, Dillingham Airfield, Pohakuloa Training Area on Hawaii island and even at Kalaupapa Airfield and the inactive 12-acre Molokai Training Support Facility, which would be reactivated.

In less than a decade, the Marine Corps plans to shift more than half of its squadrons to new aircraft, including the MV-22 Osprey, new Hueys and AH-1Z attack helicopters, the environmental study said.

The tilt-rotor Osprey, which can take off like a helicopter and fly like an airplane, has become a proven combat aircraft, flying troops in Iraq and Afghanistan.

"The incredible effectiveness and survivability of this versatile aircraft have been demonstrated again and again," Marine Corps Commandant Gen. James Amos said.

According to the environmental study, there were 52,669 aircraft operations at Kaneohe Bay in 2009, including 5,449 landings and takeoffs by practicing Air Force C-17s, one of the biggest sources of jet noise complaints. By 2018 there are expected to be 78,725 flight operations.

By comparison, in 2002 there were 90,000 airfield operations. Marine Corps officials said the increase was preceded by the closure of Barbers Point and movement of P-3 aircraft to Kaneohe Bay.