Just after 6:30 a.m., the helicopter exploded and crashed in a wooded area atop a hill just off River Road in Erwinna, across the Delaware River from Frenchtown, N.J.
The helicopter apparently took off from Brigham's home, about a mile from the crash site.
Neighbors said they heard a loud explosion near Uhlerstown Hill Road and Everbreeze Drive - a half-block from Brigham's house - and then saw flames, according to the Breaking News Network. Some also said the area was foggy.
Federal Aviation Administration records show that Brigham was licensed not only as a pilot but as a flight instructor for single-engine airplanes, helicopters, and instrument helicopters.
An FAA spokeswoman said the instrument license allows pilots to use navigation equipment when flight paths can't be determined visually - for example, in bad weather.
Brigham had been a state police pilot for two decades, flying search-and-rescue missions, manhunts, and swift-water airlifts.
"I knew him, a lot of people knew him. He was a likable guy," said Sgt. Joseph Sokolofski, commander of the Dublin state police barracks. He noted that pilots are sent across the state, so they are more widely known than stationed officers. Brigham "was really revered," he said.
The death of a longtime resident and volunteer firefighter rocked Erwinna. "Everyone knew him," one police officer said. "It's a big tragedy for the community."
Brigham and his wife, Lisa, had no children.
After retiring in January 2011, he volunteered as an airlift rescuer and worked as a private pilot with Catalyst Aviation, based in Medford.
Brigham's mother, Margaret Hoover Brigham of West Chester, "was the oldest grandchild of President Herbert Hoover," according to an obituary posted on www.RememberingPa.us. She died in 2011 at 84.
Douglas Brigham was 4 when the former president died in 1964.
The Herbert Hoover Presidential Library and Museum confirmed Brigham's lineage, according to the Associated Press.
The National Transportation Safety Board is investigating the crash. Inspectors arrived at the site around 3 p.m. and have yet to release any information.
FAA spokeswoman Arlene Salac said the aircraft was registered in Canada.
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Inquirer staff writer Bonnie L. Cook and Philly.com staff writer Frank Kummer contributed to this article.