A Kona man who pleaded guilty last year to falsely telling the FBI that a plane was about to be hijacked was sentenced today to 18 months in federal prison.

Timothy David Hershman, 59, had faced up to five years in prison for the felony charge of providing false information.

Hershman admitted calling the FBI on Jan. 17, 2013 and identifying a passenger on an Alaska Airlines flight en route from Kona to Seattle as someone who intended to hijack the aircraft.

Prosecutors said Hershman told the FBI that the passenger was a “dangerous man,” and said that the agency should “help prevent a tragedy.”

After agents confirmed that the man Hershman named was on the flight, two F-15 fighter jets from the Oregon National Guard were sent to intercept the plane and escort it into Sea-Tac airport.

Authorities interviewed the passenger for several hours before determining that the call had been a hoax.

Prosecutors had asked US District Court Judge J. Michael Seabright to order Hershman to pay more than $72,000 in restitution to compensate the US government for the cost of the F-15 escort.

The costs, as determined by a senior Air Force officer, worked out to $20,067 per hour for the 3.6-hour mission, prosecutors said in a motion filed with the court. They included fuel, maintenance, use of the aircraft and pay for the flight crews.

In a response motion, Hershman’s public defender argued that the law covering hoax cases deals with reimbursement of resulting costs to state or local governments but not federal.

Seabright ruled today in Honolulu federal court that Hershman could not afford to pay restitution.

He also placed Hersman on three years of supervised release, the federal version of probation, upon his release from prison.

During that time he is prohibited from drinking or possessing alcohol, the judge said.

Hershman had also faced a fine of up to $250,000, but no fine was assessed.

The judge ordered him to report to the federal prison in Lompoc, Calif., by March 4.

Hershman told the FBI that he had placed the call because the man had allegedly placed fish guts in his truck.