Federal officials announced the arrest yesterday of a Boeing Co. assembly-line worker who they say has admitted sabotaging a CH-47F Chinook helicopter - possibly because he was upset about being transferred to another job at the rotorcraft plant.

But investigators do not believe that the worker, Matthew Montgomery, 33, of Trevose, Bucks County, is responsible for a second - and potentially more dangerous - act of vandalism on a separate Chinook.

The Defense Criminal Investigative Service has added 10 agents to the case to find out who deliberately placed an improper washer inside the transmission of a nearly completed helicopter at the plant in Ridley Township, Delaware County.

Montgomery, who is charged with felony vandalism for allegedly severing wires inside one of the twin-engine Army choppers and who could get up to 10 years in jail, is not a suspect in the second incident, authorities said.

"It's very important that we communicate to people that this matter continues to be under investigation," U.S. Attorney Patrick L. Meehan said yesterday, in announcing Montgomery's arrest.

Montgomery, who has worked for Boeing for 18 months making $19.10 an hour, appeared yesterday before U.S. Magistrate Judge Henry Perkin in Philadelphia.

He was released on $25,000 bond and ordered to live with his parents in Southampton, Bucks County; submit to a psychological exam, and participate in mental-health counseling.

"He's very remorseful," said Mara Meehan, his public defender. "He's been pretty upset, which is one reason why concerns have been raised about mental health."

Perkin told Montgomery that the bail restrictions, which also require that no guns be present in his parents' home, are "for the safety of the community but also for your own well-being."

After his hearing, Montgomery made a beeline for a car waiting on 6th Street and declined to comment. No one answered the door yesterday at his parents' home in a well-kept Southampton neighborhood. A woman who emerged from a car in the driveway ignored a reporter's query and entered the house quickly.

Ed Bradley, a special agent, said that a $5,000 reward remains on the table for information leading to the conviction of whoever is responsible for the second act of vandalism.

Boeing management and officials from United Aerospace Workers Local 1069, the union that represents about 1,600 workers at the sprawling plant, have been cooperative in the investigation, Meehan said.

"I don't think that there's anybody that cares more about resolving it than those people whose jobs are on the line," he said of the investigation.

The Chinook production line was closed down for two days last week after workers found the irregularities and alerted the Defense Contract Management Agency, which monitors all federal contracts there. Army Criminal Investigation Command and the FBI are also involved in the investigation.

Union president John DeFrancisco said Boeing workers were shocked to hear of Montgomery's arrest and were hopeful that the incident would not affect future contracts.

"He got along with the guys, he wasn't a troublemaker," DeFrancisco said. "You would not ever suspect him of doing something like that."

DeFrancisco said he did not believe that the sabotage of the two helicopters is tied to any contract disputes or the Local 1069 union election that was held last Tuesday, the same day the production line was first shut down.

Meehan said Montgomery cut about 70 wires in a bundle the size of a fire hose on May 10, his last day on the Chinook line before being transferred to the other side of the Boeing plant to work on the V-22 Osprey.

Meehan said a "lack of appreciation for the job that [Montgomery] thought he was doing seemed to be something that may have motivated him to act out in the way that he did."

The CH-47F Chinook, a newer version of the Army's workhorse transport helicopter, has not yet been deployed in combat. The aircraft, which costs between $20 million and $30 million, is being manufactured as part of a contract to build and modernize 458 Chinooks through 2018.

Anyone with information about the vandalism is asked to call the Defense Criminal Investigative Service at 267-228-2782. *