The Navy’s ongoing efforts to swap out its aging fleet of Greyhounds is going smoothly, even if the new souped-up Ospreys won’t be fully fielded until the mid- to late-2020s.

The switch at carrier-based fleet logistic squadrons officially kicked off on Oct. 1 and the effort was boosted on Nov. 14 by a Navy announcement that a study found replacing 27 C2A Greyhounds with 38 CMV-22B Osprey tilt-rotor aircraft won’t harm the environment.

Those findings negate the need for a larger environmental impact statement. removing a key administrative hurdle from the Osprey roll out, according to Fleet Forces Command.

The Navy announced the transition in 2015 but several important decisions remain to be announced, including locations for the Osprey training squadron and the fleet logistics wing that will oversee the arrival of the aircraft across the Navy.

A workhorse of the Marine Corps, the Osprey can launch like a helicopter but fly like an airplane, but the Navy’s CMV-22B variant isn’t expected to deliver grunts to the battlefield.

Instead, it will be a top platform for providing what sailors call “COD” — carrier onboard delivery capability. The Navy’s Ospreys will be modified to maximize their ability to ferry people, , mail and spare parts from the shore to underway nuclear-powered aircraft carriers around the globe.

The reliable C-2A Greyhound has filled the role as the carrier Navy’s airline and cargo delivery service since Grumman began rolling them off the assembly line in 1965.

But now those aging aircraft have reached the limits of their service lives and need to be retired.

To better match what the Greyhounds can do, the Navy’s Osprey is configured with a larger fuel tank, more communications gear and a public address system in the rear section for passengers.

Construction of two Navy prototype Ospreys began earlier this year and they’re expected to start flying in 2019, with production models slated for delivery in early 2020.

Like the Greyhounds, the Navy plans to station a squadron on each coast. Today’s fleet logistic squadrons are located at Naval Station Norfolk in Virginia and Naval Air Station North Island in California and the Pentagon wants to move the Ospreys there, too.

Unlike most previous aircraft swaps, however, the Navy intends to stand up completely new squadrons for the Ospreys and decommission the Greyhound units when they’re ready to replace them.

At first, they’ll operate in tandem. BUt as the Osprey numbers increase the Navy will pull Greyhounds out of service. When the last of them leave, they’ll shutter the squadrons.

On Oct. 1, the Navy established Fleet Logistics Multi-Mission Squadron 30 at North Island. No timetable has been announced for when the Navy will locate a sister squadron in Norfolk — to be called VMC-40 — but officials say it is planned.

VMC-30′s initial operating capability is slated to start in 2020. That’s also when the Navy’s Ospreys should start rolling off the assembly line.

Their first deployment is slated for 2021 aboard the aircraft carrier Carl Vinson, with a complete transition expected between 2024 and 2028.

Today the fleet logistics squadrons fall under the Airborne Command and Control and Logistics Wing. It’s headquartered at Naval Air Station Point Mugu, part of Naval Base Ventura County, near Los Angeles.

A Norfolk-based detachment has administrative oversight of the East Coast squadrons.

Because the Greyhound shares a similar air frame with the Navy’s airborne early warning aircraft, the wing controls both of their fleet logistics squadrons. For the same reasons, the Norfolk-based Carrier Airborne Early Warning Squadron 120 handles training for fleet replacement aircrews for both types of squadrons.

But the Osprey effort will get its own wing and training squadron.

According to OPNAV notice 5400.2265 issued on Aug. 6, the same directive which established VMC-30, both the wing and the training squadron will be located at North Island, too.

The Navy, however, has yet to officially announce the date the unit will stand up or even where it will be located.

In the meantime, both the functions of the wing and training Squadron will be the responsibility of another unit, according to the OPNAV Notice.

The Naval Aviation Training Support Group is co-located with Marine Medium Tiltrotor Training Squadron 204 at Marine Corps Air Station New River in North Carolina.

If the flow of Ospreys continues to North Island, it will bring in 23 tilt-rotor aircraft. There are 10 Greyhound CODs there now.

According to the environmental report, that should add 341 new personnel to the San Diego area. Counting their family members, the estimate rises to 750 people.

In Norfolk, the loss of the training squadron at Chambers Field would cut the total number of aircraft from 17 Greyhounds to 15 Greyhounds. That would drop the local military population by 126 personnel, or 277 people when family members are included.

If the Navy decides to move the standalone Osprey replacement squadron to Norfolk, that would bring in 20 tilt-rotor aircraft. In that scenario, the total number of aircraft at North Island still rises from the current 10 Greyhounds to 18 Ospreys.

But if the standalone replacement squadron ends up in Norfolk, the Greyhounds would all retire by 2026,with the entire transition of the fleet wrapping up in 2028.

Both bases likely would gain personnel and family members, with Norfolk garnering 54 sailors. That rises to 119 people in Norfolk if families are included.

For North Island, that means adding 161 sailors to the San Diego area, or 354 people if family members are included in the estimates.