BOSTON (AP) – Flight delays continued Tuesday at Logan International Airport as federal officials worked to repair malfunctioning radar and controllers using a backup system added extra space between planes.

A New Jersey-based Federal Aviation Administration team that traveled to Boston to troubleshoot the system believes the problem may be an antenna at Logan, said FAA spokewoman Arlene Murray.

Another antenna was brought from Bangor, Maine, on Tuesday night, and technicians planned to test and install it overnight.

“We’ll know more in the morning if that’s going to fix the problem,” Murray said.

Some arriving flights were delayed two-and-a-half hours Tuesday evening, according to the FAA’s Web site. On Monday, when the radar surveillance system at Logan first broke down, many flights were more than four hours late arriving.

In the meantime, flights were being monitored by a long-range backup radar system in Nashua, N.H., Murray said. Relying on that system requires increasing the distance between planes from three miles to five miles, resulting in the delays.

“We’re expecting delays as long as we’re on the backup radar,” Murray said.

Starting early Monday morning, air traffic controllers began seeing blips on their radar scopes that they knew did not represent planes in flight. Murray said the problem is not common, but has occurred at other airports in the past.