PALO ALTO, Calif. — A volunteer pilot was killed and a mother and daughter he was transporting to a Northern California hospital were injured when their small plane crashed near the Palo Alto airport, authorities and the plane's operator said Tuesday.

Palo Alto Deputy Fire Chief Geoffrey Blackshire said the single-engine Mooney M20 was trying to land when it crashed in a pond Tuesday. He says the plane had reportedly flown in from Redding.

The Federal Aviation Administration says the pilot was executing a go-around at Palo Alto Airport when it crashed.

Blackshire says the injured mother and daughter were taken to a hospital by ambulance. He says one of them walked to the ambulance and the other was carried in a gurney.

Nancy Dellamaria, 49, of Redding and her daughter, 16-year-old Chloe King, were on the plane, Dellamaria's sister, Nancy Paquette, told the San Francisco Chronicle.

There was no immediate word on their conditions.

The identity of the pilot, a man in his 60s, was not immediately released.

The plane was operated by Angel Flight West, a nonprofit organization that provides free emergency medical transport to people with serious conditions who otherwise could not afford the transport, said Josh Olson, executive director of Angel Flight West.

The mother and daughter were being flown to Palo Alto from Redding because the girl had a surgery planned at Lucile Packard Children's Hospital.

Olson said pilots who fly for the group are volunteers who are qualified and vetted by the FAA and the organization typically runs between 10 and 20 flights per day on the West Coast.

The FAA and the National Transportation Safety Board are investigating.