YOKOSUKA NAVAL BASE, Japan — The USS Kitty Hawk is in the midst of its annual maintenance overhaul, a routine affair since its commissioning in 1961.

Last year, for instance, the “selected restricted availability” period added up to $40.6 million in changes over a 135-day maintenance schedule.

This year’s overhaul is scheduled for 120 days, according to ship spokesman Chief Petty Officer Jason Chudy. But don’t be quick to call it the Kitty Hawk’s last extended overhaul. Leaders on the Kitty Hawk already are planning for the carrier’s multimillion dollar spring cleaning in 2008, despite the carrier being scheduled to depart Japan permanently sometime that year.

That’s because while rumors keep flying about the Kitty Hawk’s decommissioning, the Pentagon has yet to send any official word on retiring the fleet’s oldest active ship, according to the Kitty Hawk’s public affairs office.

So before the Kitty Hawk sets sail again this spring, it will receive $35.5 million in repairs and improvements, Chudy said.

Those repairs include overhauling part of the ship’s sewage system, nine bathrooms, several berthing areas, the carrier’s landing strip, aircraft elevators and two boilers on board, according to Cmdr. Dan Carscallen, the shipboard coordinator for the overhaul project.

“Everywhere on the ship, we’ve got some kind of work going on,” Carscallen said Tuesday.

The Navy uses the Ship Repair Facility at Yokosuka as well as contractors from the Japanese firm Sumitomo Heavy Industry of Japan for the bulk of the work. All told, the project will add up to 96,000 days’ worth of work from January through mid-spring, according to Carscallen.

Because of the project’s breadth, 1,795 of the carrier’s sailors have been moved ashore, either to berthing barges or to barracks housing, Carscallen said. By the end of February, almost all of the ship’s 3,100 sailors will be ashore. The crew will start moving back on board in March, he said.