Late in the afternoon of Oct. 26, 1944, Gertrude Tompkins Silver piloted a sleek new P-51D Mustang fighter plane into thick fog that hung just west of the airfield that is now Los Angeles International Airport.

She was never seen again. Her disappearance has remained a mystery for more than six decades.

That mystery could soon be solved if years of research, planning and hard work are blessed with a little luck.

Early next month, divers from a 40-foot San Pedro-based boat called the Ranger are scheduled to make the latest -- and quite possibly last -- in a series of searches for Tompkins' plane. Descending to the ocean bottom just off LAX, they'll examine and photograph two masses of metal that crews found during the last hunt for the wreckage in 2002.

If the wreckage is indeed a plane, it should be fairly easy to determine if it's a P-51D, said Pat Macha, an aviation archaeology expert and retired Hawthorne High School history teacher who's been investigating Tompkins' fate since 1996. The P-51D's manufacturer, North American Aviation, stamped more parts than most other airplane builders. And only one P-51D crashed into Santa Monica Bay west of the former Mines Field, Macha said.

At the same time, it's far from certain that the debris is an airplane.

"It's still a long shot," said Macha, who has written three books on aircraft archaeology and has visited more than 800 crash sites during the past 40 years.

"I'm not overly optimistic but it's in a suspect location and it's metal so we have to check it out."

Macha believes this may be the last chance to find the plane flown by Tompkins, who had been married just one month when she disappeared and was still listed in military records as Tompkins. Further searches to the south -- which is the direction she would have turned after taking off -- are precluded by buoys and underwater obstacles from the Hyperion Sewage Treatment Plant, Macha said.

"I think at that point we'd have to take a large step back" if the debris turns out not to be Tompkins' plane, Macha said.

Gertrude Tompkins Silver was a member of an elite group of about 1,100 Women's Air Force Service Pilots (WASPs) who served during World War II, primarily ferrying planes for shipment overseas and pulling along aerial gunnery targets used by the military for target practice.

Tompkins became a WASP in 1943 and, at 32, was one of the older female pilots when she vanished, said her grandniece, Laura Whittall-Scherfee of Sacramento. According to Macha, she was one of 38 to 43 WASPS who were killed in crashes.

The day Tompkins disappeared, she was among a trio of WASPs who were to fly brand new P-51Ds from their manufacturing site to Palm Springs, where they would spend the night before continuing on a three-day journey to Newark, N.J.

Tompkins' takeoff was delayed by a canopy that wouldn't close properly; witnesses later reported seeing two P-51Ds buzzing east above Imperial Highway but never a third, Macha said. She wasn't reported missing until the other pilots got to Newark because they had assumed that she had been unable to take off due to the mechanical problem, he said.

"She had slipped through the cracks," Macha said.

Macha believes Tompkins went down almost immediately after takeoff. His leading theory is that the plane stalled -- possibly because Tompkins wasn't expecting that its center of gravity would be shifted by the full fuel tank directly behind the cockpit -- and went into a low altitude dive from which Tompkins could not recover. Fighters often left no debris on the ocean surface if they sliced almost vertically into the water, he said.

Macha said he had been aware of Tomkins' disappearance but got personally involved in the mystery in 1996, when he was contacted by Whittall-Scherfee.

Whittall-Scherfee said she had heard of her great-aunt as a child, but only delved into her disappearance after she and her husband, who is an aviation and history buff, moved to California. She called Macha after her husband picked up one of his books at an airplane museum.

Pilot's family gets involved

"He said if you're interested, I'm interested in running with it," recalled Whittall-Scherfee, 44. "It's a personal search and one my husband and I are very committed to."

The couple and Macha pieced together facts and a timeline by assembling information from articles, military records and witness statements. Macha organized a series of all-volunteer searches of increasing sophistication, culminating with a 2002 effort that turned up two mounds of debris close together in relatively shallow water less than a mile off Dockweiler State Beach.

The Ranger -- the San Pedro-based boat -- entered the picture because Eric Rosado was watching TV at just the right time.

Rosado was a member of the aerospace club that Macha ran at Hawthorne High School. Now 29 and a commercial diver, he stumbled upon a History Channel documentary called "Broken Wings," which profiled Macha's efforts to find Tompkins' plane.

"I said, 'Hey, I know that guy!' " Rosado said.

Soon after, Rosado volunteered his services to Macha. Five divers he works with also signed up for the endeavor, including Tyler Fenton, the 21-year-old owner and captain of the Ranger.

"All the guys have a love for the ocean," said Rosado, standing in the Ranger's cabin next to a table covered in a large depth chart of Santa Monica Bay. "We want to give back to veterans who gave to us."

Debris covered in sediment

The debris is 25 to 30 feet down, and the last search in 2002 indicated it was covered in six to 12 feet of sediment, which shifts constantly, Fenton said. Visibility in that area is anywhere from zero to 20 feet, depending on weather conditions, he said.

Wearing $5,000 diving helmets and thick black wet suits with Kevlar knee and elbow pads, divers will mark the search area with buoys and rope it off, Rosado said. They'll do a quick swim-by to see if they can spot anything right off. Then they'll stick a camera mounted on a long pipe into the sand, and use an air hose to blow away sediment so they'll be able to photograph what's underneath, he said.

Although a two-day search is planned, Rosado said the divers are willing to work as long as it takes to determine what lurks underneath the ocean floor.

Earlier this week, the crew of the Ranger visited the Western Museum of Flight at Hawthorne Municipal Airport to inspect a P-51D Mustang to get a better idea of what they might be finding under water.

Perhaps luck will be on their side. Last Sunday, while visiting the site near Victorville where a B-25 bomber went down on Oct. 4, 1944, Macha found the insignia of a WASP pilot named Marie Mitchell Robinson, who was killed in the crash along with two other crew members.

He's trying to find her next of kin to return the insignia.