WASHINGTON — The air traffic controller handling the small plane involved in a deadly crash with a helicopter over the Hudson River was chatting on the telephone about a dead cat at the airport and initially failed to warn the pilot of other aircraft in his path, officials say.

The controller tried unsuccessfully to contact the pilot before the accident, officials said Friday, and the plane collided with a tour helicopter over the Hudson River, killing nine people.

The controller handling the plane and his supervisor at Teterboro Airport in New Jersey at the time of the accident a week ago have been placed on administrative leave pending an investigation by the Federal Aviation Administration.

The National Transportation Safety Board said in a report that the controller, who has not been identified, cleared the single-engine Piper for takeoff at 11:48 a.m., then made a telephone call. He remained on the phone, including while further instructing the plane's pilot, until the accident happened.

The phone call, to an airport contractor, was a "silly conversation" concerning a dead cat that had been removed from the airport, a retired union official said.

After takeoff, the plane flew southbound until the controller directed it to turn left toward the river, the report said. At 11:52, the controller instructed the plane to contact air traffic control at nearby Newark Liberty International Airport, which is part of the procedure for handing off oversight of the small plane.

The pilot apparently did not contact Newark, the report said.

Radar data show there were several aircraft immediately ahead of the plane, including the tour helicopter, "all of which were potential traffic conflicts for the airplane," but the Teterboro controller didn't warn the pilot, the report said.

It wasn't until controllers at the Newark airport alerted the Teterboro controller to the potential collision that he twice tried unsuccessfully to contact the pilot, the report said. The collision occurred at 11:53.

At the time the Newark controllers were alerting the Teterboro controller to the danger, they also recommended the plane turn southwest. The plane's pilot apparently overhead that and acknowledged the instruction, the report said.

Video of the crash taken by a tourist sightseeing near the Statue of Liberty show the Piper changing direction seconds before its wing was clipped by the helicopter's rotors. The plane then broke apart in the air and both aircraft plunged into the Hudson.

Union officials representing air traffic controllers said the Teterboro controller couldn't have warned the Piper pilot of the helicopter in its path at the time the plane was directed toward the river. They said the helicopter was just taking off and hadn't appeared on the radar screen yet.

The FAA has said there is no reason to believe the controller's actions contributed to the accident. However, the agency said the phone conversation was inappropriate and such conduct is unacceptable. The safety board said it was too early to reach any conclusions about the crash.

The supervisor's conduct also is being investigated because he was out of the building at the time. Controllers, including supervisors, are expected to be available throughout their work shift.

Two other Teterboro controllers were taking a break at the time of the accident. The only controllers on duty were the controller talking on the phone and another controller handling other traffic.