Commuter Jet Lands at Dulles. Well, Most of It.

Aliens. They're here! thought Hilary Loewenstein when she spotted a strange metal object just off the path where she was speed-walking with her two dogs. It looked like a scrap of a spaceship, she said. Maybe aliens had landed in Maryland, she joked to herself.

The 25-pound hunk did fall from the sky, landing in a popular park in Boyds. But it wasn't a remnant of a UFO. It was a piece sent flying from a commuter jet headed to Dulles International Airport. No one was hurt, and the plane landed safely.

"We were all very lucky," said Loewenstein, 39, who made the discovery Saturday. "It's so amazing that this piece of airplane didn't fall onto the zillions of houses right behind it."

Authorities said yesterday that the piece came from United Express Flight 7350, bound for Dulles from Hartford, Conn. The Canadair Regional Jet 700, carrying 64 passengers and four crew members, had apparently shed the small door that recedes when the wheels emerge before landing at Dulles about 11:42 a.m., airline officials said.

"The landing gear door is not necessary to land the plane, because it needs to retract," United Airlines spokeswoman Robin Urbanski said. "Customers on the flight were always safe."

A spokesman for Mesa Air Group, which operated the flight for United, declined to comment yesterday other than to say an investigation is ongoing. The Federal Aviation Administration will pick up the piece from police today and try to figure out "why it fell off or what the problem was," FAA spokeswoman Laura Brown said.

"Various things fall off airplanes from time to time, but it's fairly unusual to have one of these landing-gear doors fall off," Brown said. "Airplanes are designed not to shed parts."

But this one did, and it landed in a grassy area between houses and soccer fields that often are full of dozens of children playing at South Germantown Recreational Park.

Loewenstein had been on the path around the park's perimeter just before noon Saturday when she spotted a glimmer of metal about 10 feet away. At first she thought it was a lawn chair. Then more exciting prospects came to mind.

"I really thought it was a spaceship, honest to God," she said, perhaps exaggerating just a bit. "I was like, 'Oh my God! I saw aliens! Aliens are here!' And I thought, 'How exciting!' "

She dashed to her house about a quarter mile away to tell her husband, Kevin. His interest piqued, Kevin, 38, got out of the shower and grabbed daughter Jade, 9, and son, Logan, 6.

"We hopped on our bikes, and right where she said it was there was a piece of a plane," Kevin said.