In the early hours of May 8, Palo Alto police say William James McAdams stole a plane.
The 24-year-old flight instructor flew away in the G1000 SkyHawk and then disappeared.
"Where did this plane go?" said Palo Alto police Sgt. Brian Philip.
The plane's last known location was somewhere off the coast, about 70 miles from Watsonville. The plane seemed to be heading south, but because there was no flight plan, even that's unclear, Philip said.
Police have looked into McAdams' background for clues into why he would have disappeared, but there is nothing to suggest a clear motive, Philip said.
According to Florida court records, McAdams was recently charged with domestic violence and a no-contact order was issued. He was charged April 25 with aggravated battery with a deadly weapon, false imprisonment and battery. His arraignment was set for June 2 in the Orange County Superior Court in Florida. A written not guilty plea had been submitted.
The U.S. Coast Guard was notified more than 11 hours after the first radar hit, said Petty Officer 2nd Class Barry Bena, the agency's spokesman.
Then they received information from the plane's emergency distress beacon. But no location was given.
It is possible that the distress call was unintentionally activated. Or it could have been triggered if the plane crashed into the sea, Bena said. The salty ocean water could have corroded the beacon and set it off, he said.
Searching for McAdams and the plane was going to be a challenge even based on the aircraft's last location. Based on possible speeds, wind and other factors, the Coast Guard's notification system estimated that a search would need to cover 120,000 square miles – an area about as large as the Philippines.
The area roughly stretches from the Nevada border to Humboldt County to Los Angeles, Bena said. The agency ended up suspending its search efforts, he said.
Instead, the Coast Guard notified all vessels to look out for any signs of the plane.
McAdams was working at Advantage Aviation, a Palo Alto flying club. The small Cessna was leased by a private pilot to Advantage Aviation for flight instruction, Philip said.
McAdams also operated his own aviation school, Fly High Bay Area, out of Palo Alto Airport.
According to his website, McAdams was also an aviation author who taught in central Florida and specialized in advanced aircraft general aviation training.
He was described as a career ground and flight instructor, who graduated from the Delta Airline academy.