The California Highway Patrol on Monday released a few more details about the emergency landing of a small aircraft on northbound Interstate 280 on Sunday.
The pilot, Scott Bohannon, 53, of San Mateo, was forced to land on the highway north of Farm Hill Boulevard after the plane suffered a mechanical failure, according to the CHP.
Mr. Bohannon, according to a spokeswoman from his office, is a senior vice president at Bohannon Development Corp., a noted property development company based in San Mateo. Scott is a grandson of David D. Bohannon, a legendary Peninsula developer, and the younger brother of David Bohannon, the current chief executive of the development company.
Mr. Bohannon had taken off from the San Carlos Airport on a test flight and was on his way back when the mechanical failure occurred, CHP Officer Art Montiel said. Mr. Bohannon radioed the airport as he was landing.
The CHP began to receive reports at 7:13 p.m. that a small aircraft had landed on the highway. As officers were responding, the airport also contacted the CHP about the incident.
The plane's landing gear struck the roof of a 2009 Mercedes coupe driven by Wendy Kwon, 47, of Sausalito, that was also traveling north directly below the landing aircraft, CHP officials said.
Ms. Kwon was alone in the car. The rear window of the car was broken, the roof was dented and the car was towed away from the scene, but there were no injuries.
The plane, a 1975 Cessna, landed safely and was able to come to a stop on the highway's shoulder. Traffic was light and was only moderately affected. The plane was towed to the airport.
Federal Aviation Administration spokesman Allen Kenitzer said the plane was conducting a photo mission when it lost engine power.
Landing on a freeway
That there were no injuries in this accident is probably more an indication of the pilot's skill rather than luck, said Chris Dancy, a spokesman for the Aircraft Owners and Pilots Association in Frederick, Maryland.
A pilot's first responsibility in any emergency may sound simple: fly the plane. Without an engine, a Cessna 210 becomes a glider and the pilot has full use of the controls just as if the engine were running. The links to the plane's controls are cables and rods, but nothing hydraulic that is dependent on engine power, Mr. Dancy said in a phone interview.
An equivalent responsibility is safety. "From the first time a pilot sets foot in the plane, all of the flight training focuses on safety," Mr. Dancy said, adding that the pilot is solely responsible for the safety of any flight.
The pilot's job in such a situation is to manage and mitigate risk, which includes calculating a rate of descent over the longest distance, a formula known as the best glide speed, Mr. Dancy said. If the plane is high enough above ground, the pilot has "a fair amount of time" to make these calculations, he said.
While there are no guidelines for emergency landings on freeways, they are a natural choice, Mr. Dancy said. "What is more attractive than something that looks like a runway and behaves like a runway?" he said. "If you're fortunate to be near a major highway that's got a good straightaway, that's obviously an option."
In following up on an accident, investigators from the National Transportation Safety Board typically interview the pilot and do their best to determine what caused the engine failure, including looking at the engine itself, the fuel supply and the maintenance records, Mr. Dancy said.
The NTSB is an investigatory agency. If sanctions are called for, that would be left to the Federal Aviation Administration. But with a mechanical problem and no evidence of negligence, a penalty is "highly unlikely," Mr. Dancy said.