By Emma Tucker and Andy Rose, CNN

(CNN)Two people who were on board a small plane that crashed on a Houston golf course on Friday night survived with injuries after they were extricated by firefighters, according to the Harris County Sheriff’s Office.

The single-engine aircraft was damaged in the crash, and the two passengers are “alive, but injured” and were found alert and talking, Sheriff Ed Gonzalez tweeted.

It took nearly an hour for firefighters to rescue the man and woman, who were not identified, from the plane, which was found upside down, according to CNN affiliate KHOU. The survivors were airlifted by Life Flight to a local hospital where they were treated for their injuries, according to the Texas Department of Public Safety (DPS).

“I’m always happy to report when they are alive,” said DPS Sgt. Richard Standifer. “Typically, I have to report they didn’t make it.”

Standifer said the model of the plane is a 1977 Mooney M20J, which seats up to three passengers and one pilot. It’s unclear why the plane crash occurred, he added.

The flight-tracking service FlightAware showed that the plane appeared to be on its final approach to the West Houston Airport when it went down at the Pine Forest Country Club, just north of the runway.

The Federal Aviation Administration and National Transportation Safety Board are investigating the crash, the DPS said.