Airprox Serious incident ATR 72-500 (72-212A) SE-MDC, Wednesday 20 June 2012

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Date:	Wednesday 20 June 2012
Time:
Type:	ATR 72-500 (72-212A)
Owner/operator:	Golden Air
Registration:	SE-MDC
MSN:	894
Year of manufacture:	2009
Engine model:	P&W Canada PW127
Fatalities:	Fatalities: 0 / Occupants: 76
Other fatalities:	0
Aircraft damage:	None
Category:	Serious incident
Location:	NE of Jönköping, Östergötland County - Sweden
Phase:	En route
Nature:	Passenger - Scheduled
Departure airport:	Bromma
Destination airport:	Ängelholm
Investigating agency:	SHK
Confidence Rating:	Accident investigation report completed and information captured

Narrative:
Golden (GAO) 551 with the registration SE-MDC was en route south from Bromma to Ängelholm at Flight Level 140. Approximately 30 nautical miles north-east of Jönköping, an airprox occurred with PH-DCI that had taken off from Jönköping en route to Bromma on a north-easterly heading and that was climbing to Flight Level 150.
During the airprox, there was a separation minima infringement upon which both aircraft's collision warning systems were activated. The crews of both aircraft performed evasive manoeuvres in accordance with the collision warning systems' instructions.
Air traffic control did not clearly perceive the TCAS alarm and attempted to modify the aircraft flight paths.

The minimum vertical distance between the aircraft was 300 feet at a horizontal distance of 3.24 nautical miles (nm). The minimum horizontal distance was 1.75 nm with an altitude difference of 800 feet.

The serious incident was caused by the following factors:
 The air traffic controller's focus was on an early handover of flights to another sector.
 Air traffic control's aids for noticing the conflict were not capable of breaking the mental picture that the controller had of the situation in the sector

Accident investigation: