AURORA, Ore. (KOIN 6) — The missing single-engine aircraft that left Creswell for Vancouver is a plane that is often used for training, said aviation expert Tom Young.

The Piper PA-28 Cherokee is “a very common trainer,” he told KOIN 6 News. “It’s probably been around for 50 years. It’s a safe design, depends on the maintenance how well it was kept up, possibly.”

Airplanes at the Aurora Airport, April 23, 2015 (KOIN 6 News)

Young, an airline pilot for 27 years who also served nine years in the Air Force Reserve, said many people “own them as their own personal airplanes and fly them for years, kind of like a second car.”

“It’s rare,” he said, “that you get to a spot where somebody just disappears.”

The Piper Cherokee left Hobby Field in Creswell around 4:30 p.m. Tuesday, the Oregon Civil Air Patrol said. It was supposed to land at the Pearson Air Park in Vancouver, Washington but was reported missing Tuesday evening.

Three aircraft and 15 people from the Oregon CAP are searching for the plane, whose only known passenger was the pilot.

Lee Leslie, seen in an undated photo, was last seen leaving the Creswell airport on his way to Vancouver on April 21, 2015 (Courtesy: Family friend)

The pilot was identified as Lee Cheshire Leslie, 41, from Vancouver. The 5-feet-10, 180 pound white man was last seen wearing a red polo shirt and light colored pants.

Lt. Col. Ted Tanory said that they had no new leads as to what happened to the plane.

“The FAA radar had him on track for a period of time and then he dropped off radar,” he said. KOIN 6 News learned the last known spot was over a heavily forested area that was on the original flight path.

“We are of course concentrating the search in that area,” said Tanory.

Late Thursday afternoon, CAP officials told KOIN 6 News they received a weak emergency signal within the search area, south of the Aurora State Airport and closer to Eugene.

They sent a plane and ground searchers to the area, but did not find anything, CAP officials said around 5:45 p.m.

At a press conference earlier Thursday, Tanory said there are two types of emergency signals – digital and analog. A digital burst would tell who it belongs to and provide a registration number. The older style sends an audible signal on an emergency frequency.

The signals – ELTs – must be maintained by the pilot or the plane owner. An ELT should have a battery life of about seven days, he said.

Searcher Richard Weichman said, “If we’re flying over woods, we’re looking for broken treetops or any sign of an airplane or anything that does not belong where we see it.”

Aviation expert Tom Young, April 23, 2015 (KOIN 6 News)

There are many unknowns in the case.

Young said it’s possible “there was a medical issue, possibly a situation where they wanted to vanish. Possibly they had a mechanical (issue) and didn’t get a distress call off.”

If the plane was a rental, he said an inspection by a licensed mechanic is required every 100 flight hours. He added a pilot flying their own plane must have an annual inspection.

“Typically you get an initial license as a private pilot, and that’s 40 hours minimum mandatory. It’s usually a lot more than that,” he said. “Then every two years you take a refresher flight with a flight instructor.”