By Simon Hradecky, created Tuesday, Apr 19th 2011 11:23Z, last updated Wednesday, Aug 8th 2012 14:51Z A Delta Airlines Boeing 757-200, registration N693DL performing flight DL-2086 from Atlanta,GA to New York La Guardia,NY (USA) with 130 people on board, had departed Atlanta's runway 27R on an RNAV departure route, was instructed to switch to departure frequency, the crew read back correctly but did not switch frequency. About 8 minutes later the crew reported again on tower and was instructed to immediately switch to departure, communication was established when the aircraft was at 10,000 feet 20nm east of Atlanta. In the meantime separation minima had been violated with three other aircraft. All flights reached their destinations safely.



The NTSB stated in their preliminary report, that the aircraft's radar data block did not auto-acquire on the controller displays, possibly because the transponder failed or had not been turned on, the aircraft therefore was only displayed as an enhanced primary target. After the tower instructed the crew to switch to departure the crew read the instruction back correctly but did not report on departure frequency. The departure controller remained unaware that the airplane had departed until he noticed the tower had scanned the flight strip indicating the airplane had departed, but he wasn't talking to the aircraft. The airplane, that had departed to the west, turned south and northeast following the RNAV departure route and climbed to 10,000 feet. About 8 minutes after being instructed to contact departure the crew reported again on tower, was sent onto departure frequency again and radio contact was established.



According to radar data the closest lateral proximity (no vertical distances provided) to a Beech 55 was 1.44 miles, to a Pilatus 12 0.81 miles and to a Canadair CRJ-200 2.36 miles below required minimum separation.



On Jun 6th 2012 the NTSB released their factual report adding, that the crew had not turned on their transponder upon takeoff from Atlanta's runway 27R. Procedures would require tower controller to verify that the data block auto-acquired on their radar screens before handing the aircraft off to departure, the tower controller on duty however did not notice the data block was still missing when he handed the aircraft off to departure. The crew did not contact departure. About 7 minutes after becoming airborne the crew asked on tower frequency "...you still want us down here at 10?", tower replied "DAL2086 youre supposed to be on departure sir." About 20 seconds later the aircraft reported on departure frequency.



In the meantime the departure controller had noticed he had a flight strip but no contact and no radar target and checked with tower. Tower confirmed the aircraft had departed, a search for a target showed a number of primary returns only, none of which could be positively identified as flight DL-2086. While departure, tower and traffic management controllers were still trying to identify a primary target following the assigned departure route of DL-2086, the aircraft reported again on tower.



After the aircraft finally reported on departure the controller immediately instructed the crew to verify their transponder was turned on, 6 seconds later the data block appeared on the radar screen about 20nm east of Atlanta.



On Aug 8th the NTSB released their final report concluding the probable cause of the incident was:



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.



http://flightaware.com/live/flight/DAL2086/history/20110311/1740Z/KATL/KLGA





