Introduction
On Friday, March 11, 2011, at about 1321 eastern daylight time, Delta Air Lines flight 2086 (DAL2086), a Boeing 757-200, departed from runway 27R at Hartsfield-Jackson Atlanta International Airport (ATL), Georgia, as a regularly scheduled passenger flight under 14 CFR Part 121. The flight was en route to La Guardia Airport (LGA), New York.
Flight Details
The flight crew did not activate the aircraft's transponder before takeoff and did not contact air traffic control for approximately eight 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.
During the period when DAL2086's transponder was deactivated, the airplane's flight data block did not auto-acquire on the TRACON's radar displays. 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 transfer of communications to A80, the tower controllers did not notice that the data block had not auto-acquired when the aircraft departed, and therefore did not notify Atlanta TRACON that DAL2086 had not tagged up. No radar altitude information was available on DAL2086 until the aircraft's transponder was activated.
Loss of Separation
Review of primary radar data determined that a loss of lateral separation occurred between DAL2086 and three following aircraft: N36638, a Beechcraft 55, with the closest proximity 1.44 miles; N825MK, a Pilatus PC-12, with the closest proximity 0.81 miles; and Atlantic Southeast Airlines flight 5046, a Canadair Regional Jet CRJ-100, with the closest proximity 2.36 miles. No injuries were reported on any of the flights. These incidents occurred during daytime visual meteorological conditions.
N36638 was operating under 14 CFR Part 91 from Clayton County - Tara Field (4A7), Hampton, Georgia, to John C Tune Airport (JWN), Nashville, Tennessee. N825MK was operating under 14 CFR Part 91 from DeKalb-Peachtree (PDK) airport, Atlanta, Georgia, to Sarasota/Bradenton International (SRQ) airport, Sarasota, Florida. ASQ5046 was a regularly scheduled passenger flight from Augusta Regional (AGS) airport, Augusta, Georgia, to ATL, operating under 14 CFR Part 121.
Aftermath
At about 1318, the ATL tower LC-3 controller instructed DAL2086 to line up and wait at the displaced threshold of 27R. One minute later, the controller instructed DAL2086 to take off. DAL2086 had filed the UGAAA 2 RNAV standard instrument departure (SID) from runway 27R.
At about 1320, one minute after DAL2086 was airborne, the LC-3 controller instructed the pilot to turn left to FUTBL and contact departure. The pilot read back the instructions correctly but did not contact departure control until about 1328.
According to the LC-3 controller, when DAL2086 departed, he did not notice that the flight had failed to auto-acquire because his attention was temporarily drawn to a situation at the approach end of runway 27R.
At about 1324:54, the Atlanta TRACON south departure controller (DEP-S) realized he had an unaccounted for flight strip on DAL2086 and asked ATL tower about the status of the flight. The LC3 responded that DAL2086 had departed but they would check into it. The LC informed the Traffic Management Coordinator (TMC) who began searching the Traffic Situation Display for a target. According to the TMC, he saw a target approximately 40 miles northeast of ATL that appeared to be DAL2086, but review of radar data indicated that DAL2086's primary target was approximately 11 miles south of ATL. Due to the large number of primary targets, the TMC could not positively identify which target was DAL2086.
At about 1326:53, DAL2086 contacted ATL tower asking if they still wanted them down at 10. The LC responded that DAL2086 was supposed to be on departure. The LC immediately informed the DEP-S controller. Twenty seconds later, DAL2086 contacted departure. The DEP-S controller asked for their position. DAL2086 reported being just off the east end of the runway. The DEP-S controller requested that the pilot verify his transponder was on. Six seconds later, the pilot reported the transponder was on, and the airplane's radar data block appeared on the controller's radar display. Radar data indicated DAL2086 was approximately 20 miles east of ATL. Due to proximity to arrival traffic, the departure controller expedited DAL2086's climb to 14,000 feet, and at about 1329 established radar contact. The flight continued to New York LaGuardia without further incident.