BOSTON (AP) -- New signs and closer supervision of planes as they taxi along the runways at Logan International Airport are among the safety precautions being taken following a series of incidents on Logan's intersecting runways.
Since last September, Logan has seen 12 so-called ''incursions,'' in which planes have been cleared for takeoff only to find another aircraft blocking the runway. Only one of those was considered serious - an incident involving two passenger jets that narrowly avoided a high-speed collision.
The most recent incursion earlier this week prompted officials from the Federal Aviation Administration and the Massachusetts Port Authority, which manages Logan, to unveil a new runway safety plan on Wednesday.
''As long as we have humans at airports we are going to have incursions,'' said Harry West, manager of the FAA's runway safety program for the northeast region. ''What we want to prevent are the really serious events.''
The safeguards include new signs that will better indicate where planes should stop. Also, Massport officials will now escort all planes being moved around the airport for maintenance.
Massport and the FAA are also summoning the chief pilots from several airlines to Logan next week to discuss the new procedures and any additional steps that could be taken to improve safety.
''We are going to put out heads together and turn this thing around,'' said Massport aviation director Tom Kinton.
On Monday, a FedEx cargo plane crossed the path of a JetBlue passenger jet about to take off, but air traffic controllers were able to warn the JetBlue pilots before the plane started rolling down the runway.
On a scale of A to D, that incident was a D, officials said Wednesday. But the June 9 near-collision at Logan ranked at the top of the scale.
On that day, a US Airways Jet traveling at 167 miles per hour crossed paths with an Aer Lingus plane taking off at 198 miles per hour. The two jets came within 171 feet of each another where two of Logan's runways intersect.
That and other lower-level incursions prompted aviation officials to study ways to make Logan's runways safer.
FAA and Massport officials said there are several possible culprits to blame for Logan's higher-than-average number of incursions. Nationwide the number of incursions have dropped slightly even as Logan's has spiked.
They point to the airport's cramped layout, the disruption caused by the ongoing construction of a sixth runway, and even the gradual change in the ratio of jet planes to propellor driven planes using the airport.
But unlike similar problems in the past, officials say they are unable to point to one problem at the root of the higher number of incursions.
''There is no single thing that we can get at,'' said Kinton.
The nation's 17th busiest airport is located on a mostly man-made peninsula jutting into Boston Harbor, with five runways, all of them intersecting. The runway now under construction will also cross the other runways.
Copyright 2005 Associated Press