A San Francisco hang glider died Sunday, after witnesses say that he flew straight into a Fort Funston cliff.

San Francisco Fire Department Battalion Chief Jeff Barden says that crews including an officer from the U.S. Park Police, a lifeguard with the National Park Service, and a U.S. Park Ranger were called to Fort Funston in the Golden Gate National Recreation Area at 3:50 Sunday afternoon.

When they arrived, they found a 69-year-old Rafael Lavin of San Francisco about 30 feet below a cliff near the hang glider launch area. Though first responders performed CPR on Lavin, he was pronounced dead by an SFFD medic at 4:23.

Barden says that witnesses watched Lavin hang glide "straight into the cliff without trying to steer away."

It's possible, Barden says, that Lavin experienced a medical event such as a heart attack that prevented him from steering his craft away from the cliff. He also "could have got caught in an updraft of wind," Barden says.

Still other witnesses reported that the collision occurred just moments after Lavin took off, and could have been a case of mechanical failure.

According to a statement sent by the NPS, the event remains under investigation.

KRON4 reports that Sunday's fatality was the second Bay Area hang gliding accident this past weekend. "On Saturday afternoon a man was caught in telephone poles and wires as he was hang gliding in Daly City."

"From what we know," KRON4 writes, "firefighters were able to untangle his glider and get him down safely."