Staff of the US National Transportation Safety Board (NTSB) are investigating a near midair collision of a US Airways Airbus A319 and a Cargolux Boeing 747.
The incident occurred on 21 May at Anchorage International airport when the two aircraft came within an estimated 100ft vertically and within .33 mile of laterally as the Cargolux 747 was departing the airport and the A319 was executing a go-around.
The US Airways A319, inbound from Phoenix on runway 14, had 138 passengers and crew onboard. The 747 was departing Anchorage en route to Chicago on runway 25R.
NTSB says the incident occurred at 12:10am Alaska Daylight Savings Time in night visual meteorological conditions with 10 miles of visibility.
The Traffic Collision Avoidance System (TCAS) report from the A319 crew shows that as the airport was approaching Anchorage the crew initiated a missed approach due to the effects of tailwinds in the approach path.
NTSB explains the tower controller instructed the A319 to turn right, heading 300 and report the departing 747 in sight.
Once the A319 crew reported seeing the 747, the controller instructed the US Airways crew to maintain visual separation from the 747, climb to 3,000ft and turn right heading 320.
The A319 refused the right turn "because the turn would have put their flight in the direct conflict with the 747", says NTSB. The crew then received a resolution advisory to monitor vertical speed and the pilots flying the A319 complied with the descent command.
But during descent the A319 pilots lost sight of the 747, and at about 1700ft above ground level the A319 crew received and aural "clear of conflict" command.