Henry Rosenau, 61, of Armstrong, B.C., pleaded guilty Wednesday to conspiracy to import marijuana, the U.S. Department of Justice said in a news release. The guilty plea came hours before Rosenau's trial was scheduled to begin.
Rosenau admitted that between 2000 and 2005, he flew dozens of loads of so-called "B.C. Bud" marijuana into forested areas in Washington, Idaho and Montana, the department said.
Rosenau also flew other Canadians into the U.S. to work as offloaders and transporters for the drug shipments.
In 2005, the RCMP confronted Rosenau in Canada after one of his trips. The Mounties searched the helicopter and found a loaded handgun, night vision goggles, two satellite phones and a GPS device that contained the locations of landing sites used by marijuana traffickers.
Rosenau will be sentenced in October. The charge carries a minimum sentence of five years in prison and maximum of 40 years.
More than 40 people were indicted after a U.S. Immigration and Customs Enforcement investigation dubbed Operation Frozen Timber, which was looking into allegations that smugglers were transporting B.C. marijuana into the United States and cocaine into Canada.
Canadian and American authorities intercepted more than 17 drug loads, including a February 2005 shipment in which five suitcases were found containing 169 kilograms of cocaine.
"Rosenau and his co-conspirators thought they had the perfect plan to smuggle drugs into the United States, but obviously they were mistaken," Brad Bench, a special agent with the U.S. customs agency, said in the news release.
"Treacherous terrain, remote locations and the use of aircraft didn't shield these criminals from justice."
Rosenau was formally indicted in 2006, but spent years fighting his extradition. He lost in B.C. Supreme Court and the B.C. Court of Appeal. The Supreme Court of Canada refused to hear the case last year, exhausting Rosenau's final avenue of appeal.
He also filed lawsuits in Canada against witnesses, law enforcement and prosecutors. He has agreed to drop those cases as part of his plea agreement.