Iwo Jima is a training site like no other. The rugged volcanic crag was one of the most iconic battlegrounds of World War II, and is so isolated and barren it has almost never been inhabited by anyone other than military troops. But from the perspective of U.S. Navy fighter pilots who regularly train on the island's one functioning airstrip, it is unique in another way.

If a plane finds itself in serious trouble and for some reason that lone airstrip on the island isn't viable, the only alternative is to eject and ditch in the Pacific. It's a problem that the U.S. Navy, which is now conducting training on the island to prepare pilots for deployment to the USS George Washington aircraft carrier, has been trying to fix for nearly 25 years.

But, so far, Japan has failed to find a more suitable site.

Briefing reporters on the tiny island Friday, Capt. Dennis Mikeska, the assistant chief of staff for operations, planning and operations for the U.S. Naval Forces, Japan, said Iwo Jima is the only place in the world where the Navy conducts crucial carrier landing practice without an emergency "divert" _ an alternate location where a plane can go in an emergency.

He said the Navy hasn't lost a plane on Iwo Jima yet, but added, "That's not to say there haven't been any close calls."

Mikeska was quick to note that although the site is not so critically dangerous as to be unusable, it does not meet Navy safety standards and must be replaced as soon as possible.

Japan is responsible for providing locations for all U.S. bases within Japanese territory that both countries agree are necessary. The Navy's plea has run up against the classic dilemma that faces all U.S. forces in Japan. Though the Japanese government is one of Washington's staunchest and most reliable allies, it is virtually impossible to find a city, town or village that will quietly accept having U.S. troops based near it.

The not-in-my-backyard problem is most intense on the island of Okinawa, where about half of the 50,000 U.S. troops in Japan are based. Plans to simply deploy the Marine Corps' new transport aircraft, the MV-22 Osprey, have sent tens of thousands of Okinawans to the streets in protest.

This week, the mere suggestion by the mayor of Japan's second-largest city that the U.S. should use a small suburban airfield there was met with an immediate outcry, and has become a national debate.

For the Japanese leadership _ who are rarely willing to risk such controversy _ Iwo Jima is the perfect place to put the noisy U.S. fighters.

Now officially called Ioto in Japan, the island is inhabited full time only by a few hundred Japanese troops. It is about 750 miles (1,200 kilometers) south of Naval Air Facility Atsugi, the base on Japan's main island where the George Washington aircraft carrier's air wing _ the units that train on Iwo Jima _ is stationed when not at sea.

Local anger over the noise and dangers of a crash are what drove the wing to Iwo Jima to begin with.

With little other choice, the Navy has been using the Iwo Jima facility for carrier landing practice since 1989, when the two governments agreed to move such operations there "on an interim basis" in response to the noise complaints, and costly lawsuits, from Atsugi residents.

Carrier-based fighter pilots need to train intensely and are required to take qualification tests before deploying to sea. The strip on Iwo Jima has a mock-up of an aircraft carrier's deck. Veteran pilots stand nearby as the fighters approach, both to guide them in and to grade each landing.

Iwo Jima has its advantages. Because there is no local population to worry about, fighters can fly at low altitudes and at all hours of the night. But according to the Navy, the nearest place a pilot can "divert," or make an emergency landing, is 600 miles (960 kilometers) away, or about six times farther than the 100 miles (160 kilometers) that is considered safe.

"We need a special waiver every time we train out there," said Jon Nylander, a spokesman for the U.S. Navy in Japan. "Moving it is a high priority for us."

Tokyo has acknowledged Iwo Jima is only a temporary solution.

Japan has suggested the Iwo Jima flight training be conducted on Mageshima, an island in Japan's southwest where Tokyo plans to build a military base to bolster its southern defenses and its preparedness for natural disasters. Mageshima was officially named a candidate in 2004 in a meeting between the U.S. and Japanese foreign and defense ministers.

Mageshima would provide access to alternative landing sites, and would also be closer to the home base of the air wing when it moves to Iwakuni, about 250 miles (400 kilometers) away. That move was scheduled for 2014, but has also stalled.

No progress has been announced on moving to that island, however.

Mikeska said Mageshima is still officially a candidate site, but no firm plans have been agreed upon.