BOEING 757-232 near ATLANTA, GA — 2011-03-11

Probable cause

The air traffic controllers’ failure to adhere to required radar identification procedures, which resulted in loss of separation between the departing Boeing 757 and three other airplanes. Contributing to the incident was the pilots’ inadequate preflight checks, which resulted in the airplane departing with an inoperative transponder.

NTSB narrative

A Boeing 757-200 departed from Atlanta, Georgia, without its transponder activated, and the pilots did not contact air traffic controllers for about 8 minutes after departure. The airplane flew through one controller’s airspace and entered another controller’s airspace without coordination before radar and radio contact was established. While the incident airplane’s transponder was not activated, the airplane’s radar data tag (which contained identification, altitude, and airspeed information) did not automatically appear on the controllers’ radar displays as it normally would have. Consequently, the airplane was displayed only as an enhanced primary target with no identifying information. Although local procedures require that Atlanta tower controllers verify that departures have a radar data tag before transferring communications to departure controllers, the tower controllers did not do so. Review of primary radar data determined that a loss of lateral separation occurred between the incident airplane and the following three airplanes: 1) a Beechcraft 55 (closest proximity 1.44 miles); 2) a Pilatus PC-12 (closest proximity 0.81 miles), and 3) a Canadair Regional Jet CRJ-100 (closest proximity 2.36 miles).

Analysis

Primary failure mode

Human factors

First missed decision gate

Flight crew failed to activate transponder before takeoff.

NTSB coding

• Air traffic event · Initial climb
• Planning / Preparation

Evidence available

• ADS-B / radar
• 11 docket documents

Docket documents11

• ATC 3 - Certificate of Party Representativeatc
• ATC 3 - Controller Statement ATL ATCTatc
• ATC 3 - Daily Record of Facility Operations A80atc
• ATC 3 - Daily Record of Facility Operations ATL ATCTatc
• ATC 3 - Factual Report of Group Chairmanatc
• ATC 3 - Flight Progress Strip DAL2086atc
• ATC 3 - Memorandum From Support Office ATLatc
• ATC 3 - Memorandum from District Manager to A80 and ATLatc
• ATC 3 - Plot of DAL2086's Flight Pathatc
• Operations 2 - Attachment 1other
• Operations 2 - Factual Report of Group Chairmanreport