Air traffic controllers at Logan International Airport say their ability to monitor taller ships that could interfere with landings and takeoffs on two main runways as they traverse Boston Harbor is being compromised after recent technological and administrative changes.
First, a video camera at the Conley Container Terminal that had been used to spot ships with masts higher than 85 feet had been inoperable for parts of the past two years and was only recently replaced.
In addition, controllers have been told to stop using the airport's ground radar system to help detect the ships passing by the end of Runway 4R after the Federal Aviation Administration issued a directive in early March.
Without the cameras and radar, and until they are trained to operate a new camera, controllers say they must depend on daily reports from Boston Harbor pilots on whether a taller ship will be passing by the runway. Controllers say that system is not dependable, especially if a ship does not require a harbor pilot's help.
"Without a system telling us how high a ship is, in bad weather we have to treat them all as if they are too high," said Bob Romano, president of the Boston chapter of the National Air Traffic Controllers Association. He said the potential conflicts between ships and airplanes regularly come up whenever Runway 4R is in use, which largely depends on weather and wind conditions.
Both the Federal Aviation Administration and the Massachusetts Port Authority, which runs the airport, acknowledge the issue but said that they are working on a solution and that safety is not being jeopardized.
In addition to training controllers to use a new camera recently installed at Conley Terminal, Massport officials are talking to vendors about the future installation of infrared cameras that would let air traffic controllers see ships passing in the night or in bad weather, and even calculate their height.
Taller ships have been a longstanding issue at Logan. However, the problem reemerged last year after a team of FAA experts came to Logan to investigate a rash of runway near-collisions and other incidents. By the end of last year, Logan had had 17 runway incidents in 14 months.
The Port of Boston's main shipping channel serving the Conley Terminal sits directly off the end of Logan's Runway 4R, which is used for landings, and 22L, which is used for takeoffs.
Because of that proximity between ships and planes, air traffic at the airport can be affected by ships as tall as 85 feet or higher, said FAA spokesman Jim Peters.
Runway 4R is the only runway pilots can use for certain instrument landings when inclement weather prevents controllers from guiding a pilot into Boston. But if a ship passing Runway 4R is 176 feet or higher, Peters said no instrument approaches are allowed on the runway. If a ship passing Runway 4R is between 85 feet and 176 feet, instrument approaches to Logan are safe but more difficult, he said.
Thomas Kinton, director of aviation at Massport, said any delays caused by a passing ship are minimal, with quick adjustments made by controllers to allow the flow of takeoffs and landings to continue.
FAA files show only one complaint in the last two years about ship traffic interfering with airport operations. In December 2003, a Logan controller filed an "unsatisfactory condition report" with the FAA, saying the tracking of jack-up barges with masts more than 200 feet high "is insufficient."
"These are not to be overflown by aircraft landing on Runway 4R or departing Runway 22L," wrote controller Randolph Arslanian. "The inbound reports by barge captains are ambiguous. They may vary as much as an hour before they arrive in the harbor channel."
Kinton has requested that a special FAA team come to Logan to examine the situation, and Peters said the FAA is "looking favorably" at that request.
Several of Logan's recent near-collisions occurred when pilots crossed onto active runways, despite warnings from air traffic controllers and radio reminders.
In all, there have been four such lapses since June 9, and authorities are discussing ways to improve safety at the airport, whose runway layout is particularly cramped.
An American Airlines jet was forced to abort its takeoff at the Boston airport when an American Eagle plane crossed onto its runway.