Safety System Gives Pilots False Alarms

The Federal Aviation Administration says it may temporarily stop using some equipment that has falsely warned pilots of possible mid-air collisions.

But the agency said there was no threat to safety from the ghost aircraft images that have appeared on the cockpit display of the traffic alert and collision avoidance, or T-CAS, anti-collision system.

In the last three weeks there have been a series of incidents, several in the Chicago region, in which pilots spotted false T-CAS images and took evasive action to avoid a nonexistent danger, FAA spokesman Paul Steucke said.

Steucke said the incidents are believed to occur when a T-CAS unit picks up a faint signal from an aircraft that is much farther away than the distance in which T-CAS is designed to operate.

The equipment in question, about a third of the estimated 700 T-CAS sets now in use, was manufactured by Collins Avionics, a division of Rockwell International.