On May 21, 2010 at 0010 Alaska daylight savings time (AKDT), at the Ted Stevens International Airport, (ANC) Anchorage, Alaska, US Airways flight 140, an Airbus A319, arriving from Phoenix Sky Harbor International Airport with 133 passengers and a crew of 5 experienced a near mid air collision (NMAC) with Cargolux 658, a 747, departing ANC, with a crew of 2 destined for the Chicago O'Hare International Airport (ORD). The A319 received a traffic collision avoidance system resolution advisory during the incident. The ANC airport was configured to use runways 14 and 25R that intersect; runway 25L was closed for construction. The A319 was landing on runway 14 and the 747 was departing from runway 25R. Use your browsers 'back' function to return to synopsisReturn to Query Page
The 2353 weather at the time of the incident reported wind 290 at 6 knots, visibility 10 statute miles, few clouds at 2,500 feet, scattered clouds at 6,500 feet and 20,000 feet. The temperature was 14 degrees Celsius and the dew point was 2 degrees Celsius. The altimeter was 29.79 inches of mercury.
The A319 was inbound on a visual approach to runway 14 and communicating with the ANC approach controller. While the A319 was approximately five miles from the landing threshold of runway 14 the ANC tower local controller cleared the 747 for departure from runway 25R. When the A319 was approximately two miles from the approach end of runway 14, and after being prompted by the tower local controller, the approach controller directed the A319 to contact the tower. The A319 acknowledged the instruction but did not contact the tower. The tower local controller made several attempts to establish communications with the A319 without success and did not attempt to contact the A319 on the emergency guard frequency, 121.5.
Approximately 1 mile from the landing threshold of runway 14, at 600 feet and 180 knots ground speed, the crew of the A319 informed the approach controller that he had encountered a "tailwind" and was executing a missed approach. The approach controller directed the crew of the A319 to fly heading 190 degrees and maintain 2000 feet.
Immediately after the A319 began the missed approach, the tower called approach control and asked if he was talking to the A319. The approach controller advised the tower controller that the A319 reported a "wind shear" and was going around. The tower controller asked the approach controller to put the A319 on a heading of 160 due to the departing 747 departing runway 25R. The approach controller responded that he was going to turn the A319 "all the way to the right".
The approach controller instructed the A319 to turn right heading 300 degrees and informed him that traffic had just departed runway 25R that would be turning southbound. The A319 acknowledged the heading assignment. The approach controller asked the crew of the A319 if he had the 747 in sight and the A319 responded that he did not have the traffic in sight.
According to controller interviews, the approach controller had misunderstood the tower controller's instructions to have the A319 fly a heading of 160 degrees to de-conflict with the 747 departing runway 25R. The approach controller thought the local controller was going to turn the 747 to a heading of 160 degrees to de-conflict with the A319 on missed approach. The approach controller acknowledged that he did not note A319's airspeed and assumed the A319 was maintaining a standard approach/missed approach speed when he issued the 300 degree heading. Accordingly, the approach controller said his decision to turn the A319 to a heading of 300 degrees after a runway 14 missed approach was based on his experience that aircraft of the Airbus 319/Boeing 737 class/size aircraft would be able to complete a turn to a heading of 300 degrees while remaining north of runway 25R.
The local controller observed the developing conflict and instructed the 747 to turn left heading 190 degrees and to maintain 2000 feet; however, the 747 did not respond. The local controller followed with two additional transmissions instructing the 747 to maintain 2000 feet without receiving a response. The 747 had switched frequencies from local control to departure control prior to being directed to do so by the local controller. At the time of the event, the local controller was not able to communicate with the A319 or the 747.
As the A319, on the runway 14 missed approach, overflew over the 747 departing runway 25R, the crew of the 747 made initial contact with the approach controller and reported that the flight was at 800 feet climbing to their initial assigned altitude of 4000 feet. The approach controller did not acknowledge the 747 immediately, but issued control instructions to several other aircraft he was working at the time.
The A319 then reported that he had the 747 in sight and the approach controller directed the A319 to maintain visual separation from the 747, turn right heading 320 degrees and to maintain 3000 feet. The A319 acknowledged the heading and altitude assignment but did not acknowledge the directive to maintain visual separation.
As the A319 passed over the 747 and started a right turn to 300 degrees, the flight paths of the two aircraft diverged. According to the first officer of the A319, who was the pilot flying, they were to the left of the 747. When the pilot finally was able to visually identify the location of the 747, the airplane was at the low 4 o'clock position relative to the A319.
The controller assigned heading of 300 degrees would have put the A319 and the 747 on a conflicting course so the pilot of the A319 stopped this turn momentarily on a 270 degree heading. The A319 and the 747 flew a parallel flight path momentarily. The approach controller directed the A319 to maintain visual separation from the 747 and to fly heading 320 degrees and climb to 3000 feet. The 747 was climbing to 4000 feet on a heading of 249 degrees. As the A319 started a right turn to 320 degrees, the flight paths of both aircraft converged and the A319 received a resolution advisory to descend and nearly flew under the 747 as the A319 turned from a 270 degree heading to a 320 degree heading. The 747 took no action to avoid the A319. According to recorded radar data, the 747 and the A319 came with 100 feet vertically and .33 miles laterally.