NTSB Identification: CHI89IA179.
The docket is stored on NTSB microfiche number 41977.
Scheduled 14 CFR operation of TRANS WORLD AIRLINES INC.
Incident occurred Tuesday, September 05, 1989 in KNOX, IN
Probable Cause Approval Date: 10/08/1992
Aircraft: BOEING 767-231, registration: N608TW
Injuries: 6 Minor,156 Uninjured.

NTSB investigators used data provided by various sources and may not have traveled in support of this investigation to prepare this aircraft incident report.

THIS AIRPLANE WAS INVOLVED IN A NEAR COLLISION WITH ANOTHER AIRPLANE WHILE IN POSITIVE CONTROL AIRSPACE. BOTH AIRPLANES TOOK EVASIVE ACTION. VISIBILITY WAS REPORTED BY BOTH FLIGHT CREWS AS BEING REDUCED BY THE PRESENCE OF CIRRUS CLOUDS WITH NO VISIBLE HORIZON. THIS AIRPLANE HAD ACKNOWLEDGED AND RESPONDED TO A TURN INSTRUCTION ISSUED TO A THIRD AIRPLANE WITH A SIMILAR CALL SIGN, AND TURNED TO A HEADING WHICH PUT THE TWO INVOLVED AIRPLANES ON AN INTERSECTING COURSE. THE TURN INSTRUCTION WAS CHALLENGED BY THE AIRPLANE FOR WHOM IT WAS INTENDED, BUT THE INCIDENT AIRPLANE WAS NEVER TURNED BACK TO ITS ORIGINAL HEADING. THE ERROR WAS DISCOVERED A SHORT TIME LATER BY THE MANUAL CONTROLLER AND POINTED OUT TO THE RADAR CONTROLLER. HE ISSUED TURN AND CLIMB INSTRUCTIONS TO THE INCIDENT AIRPLANE ALONG WITH A TRAFFIC ADVISORY. CORRELATION OF THE TWO DFDR READOUTS WITH RADAR TRACK DATA SHOW, THAT AT THE POINT OF CLOSEST APPROACH, VERTICAL SEPARATION WAS BETWEEN 95 AND 200 FT.

The National Transportation Safety Board determines the probable cause(s) of this incident to be:

THE RADAR CONTROLLLER'S FAILURE TO MAINTAIN RADAR SEPARATION. FACTORS CONTRIBUTING TO THE INCIDENT WERE: MISUNDERSTANDING OF AN ATC INSTRUCTION BY THE PILOT OF THE INCIDENT AIRPLANE, AND UNCLEAR PHRASEOLOGY USED IN THE INSTRUCTIONS ISSUED BY THE RADAR CONTROLLER.

Index for Sep1989 | Index of months