Navy mail plane was sent out to find the Japanese fleet, its crew armed only with old rifles.

The tattered Pearl Harbor survivor looks every bit of 78, with weathered skin, rusty bones and the faded “U.S. Navy” emblem the old bird got before the war.

Gray from age and years in the service, the veteran of Dec. 7 sits with other World War II antiques, weary and in need of attention.

But with the 75th anniversary of the 1941 attack today, and commemorations scheduled in Hawaii and around the country, this survivor, like most who were there that day, has a story.

The ungainly Navy airplane at the National Air and Space Museum’s Udvar-Hazy Center in Chantilly, Va., is one of the few original U.S. aircraft in existence that flew against the Japanese armada that day.

Then painted silver and orange-yellow, with a bright green tail and red trim, it was an unlikely combatant.

Designed as a small airliner — a “baby clipper” — it was unarmed and part of a unit called Utility Squadron One, which hauled mail, sailors and Navy photographers around the Hawaiian Islands.

It had window curtains and a restroom with porcelain fixtures. Its top speed was just over 100 mph.

With Pearl Harbor a scene of death and devastation that Sunday morning, Plane No. 1063 — its insignia a pelican carrying a mailbag — was ordered to seek out the enemy.

For armament, the 28-yearold pilot, Ensign Wesley Hoyt Ruth, and his five-man crew were issued three World War I-era rifles.

Their task: Report the location of the six Japanese aircraft carriers, two battleships, assorted escort ships and hundreds of enemy airplanes that had been in on the attack.

“This is going to be a oneway trip,” Ruth later said he thought. But it wasn’t. Seventy-five years later, the Sikorski JRS-1 amphibian, with its boat hull for the water and big tires for the runway, sits in the center’s restoration hangar, a venerable witness to the event that helped create modern America.

The Pearl Harbor attack, which plunged the United States into World War II, killed an estimated 2,400 Americans, wounded about 1,100, and destroyed ships, planes and facilities.

“The fact that [Ruth] got out and got back is ... absolutely amazing,” Smithsonian museum specialist Pat Robinson said last month.

The plane would not have survived an encounter with the Japanese fleet, which it did not find, Robinson said in an interview at the center.

It was lucky not to have been shot down by jumpy American antiaircraft gunners when it returned to Pearl Harbor, he said.

And it was a miracle that it was saved from the postwar scrap heap.

“Somewhere ... someone looking at the log books realized the significance of the airplane, and where it had been” and alerted the Smithsonian, which retrieved it from military storage, Robinson said.

“It’s a huge deal, to have this here,” he said. “It represents American involvement in the Second World War. It was there when it started.”

Indeed, the airplane has a presence, and the Smithsonian would one day like to restore it. But other historic planes are in line ahead of it.

The craft is big, with the two huge propeller engines built into the wing above the fuselage, a hatch in the nose where a photographer could stand, and porthole-style windows.

The plane was constructed for the Navy in 1938 at the Sikorsky plant in Stratford, Conn. Inside, the curators found an old emergency water purification kit and the rusted keys to a lock box in the radio compartment.

The squadron was based on Ford Island, in the middle of Pearl Harbor, where the Navy’s doomed battleships were parked.

Ruth, the pilot, who later lived in the Washington area and taught at the Bullis School in Potomac, Md., was in his bachelor’s quarters on the island the morning of the attack.

A seasoned aviator, “he could fly anything,” his son, Thomas A. Ruth II, said recently.