It's been a weird two days at Porterville's Municipal Airport.

One plane crashed into an airport sign and another overturned. The explanation: there isn't an explanation, said pilots who reported a "pulling" before the planes crashed in separate incidents.

It all started late Friday morning when the pilot of a small aircraft was landing at the rural Porterville airport on South Newcomb Street. The pilot, who police didn't identify, told officers she was landing when her "aircraft began pulling."

She couldn't control the plane and slammed into an airport marker near the end of the runway. She wasn't injured in the crash. It's not known if there was anyone with her in the plane at the time.

The plane, and sign, had little damage and the pilot was able to taxi the plane toward the hangars. She notified authorities who then called police.

Less than 24 hours later, another pilot is lucky to be alive after his plane overturned on takeoff Saturday morning.

Again at Porterville's city-run airport, an unidentified pilot was preparing for takeoff when the "pulling" began. Around 9:10 a.m., 911 calls flooded the city's dispatch center when airport officials notified emergency personnel that a plane was "down."

"His aircraft began pulling to the left and veered off the runway and into the dirt field," Sgt. Brian Nix said. "As he attempted to maneuver the aircraft to recover, it began to lift and ultimately overturned."

Firefighters, paramedics and police rushed to the scene. The pilot wasn't injured, Nix said.

The plane suffered moderate damage.

The National Transportation Safety Board and FAA were notified of the separate crashes and will likely begin investigating the phenomena.

Porterville Municipal Airport was founded in 1946 when the property was transferred to the city from the United States military.

Previously, the airport was operated as the Porterville Army Airfield. The Army Air Corps opened the airfield in September 1942 and it was used by the United States Air Force, according to the city.

It was also used as a Lemoore Army Airfield training sub-base and for coastal patrols using the B-25 aircraft.