Nct controllers described a loss of separation event when late night airspace configurations were no...

Attributes
ACN	887151
Time
Date	201005
Local Time Of Day	1801-2400
Place
Locale Reference	NCT.TRACON
State Reference	CA
Aircraft 1
Make Model Name	Cessna 425/441 Conquest I/Conquest II
Flight Phase	Descent
Route In Use	Vectors
Flight Plan	IFR
Aircraft 2
Make Model Name	Skyhawk 172/Cutlass 172
Flight Phase	Cruise
Route In Use	None
Flight Plan	IFR
Person 1
Function	Departure Approach
Qualification	Air Traffic Control Fully Certified
Person 2
Function	Approach
Qualification	Air Traffic Control Fully Certified
Events
Anomaly	ATC Issue All Types Conflict Airborne Conflict Deviation - Procedural Published Material / Policy

Narrative:

[There were] several crossing/conflicting traffic situations. Aircraft Y was handed off via automation to and communications transferred to sunol sector. I had taken radar contact via automation on aircraft X inbound to mhr from sunol. Aircraft X had not checked in on my frequency. I last noticed aircraft X descending through 16000 ft. Standard operating procedure is 'descending to 14000 or lower filed altitude'. I was resolving other conflicts when the collision avoidance (ca) alarm sounded. Aircraft X was descending through 11800 and was within 5 miles of aircraft Y on a converging course. I broadcasted to aircraft X to stop descent and climb immediately to 12000 ft and issued the traffic (aircraft Y). Aircraft X was on frequency; responded and complied. Recommendation; comply with the SOP and 7110.65. Transfer communication prior to entering the receiving controller's airspace.

Original NASA ASRS Text

Title: NCT Controllers described a loss of separation event when late night airspace configurations were not clearly understood leading to confused coordination and the error.

Narrative: [There were] several crossing/conflicting traffic situations. Aircraft Y was handed off via automation to and communications transferred to Sunol Sector. I had taken RADAR contact via automation on Aircraft X inbound to MHR from Sunol. Aircraft X had not checked in on my frequency. I last noticed Aircraft X descending through 16000 FT. Standard Operating Procedure is 'Descending to 14000 or lower filed altitude'. I was resolving other conflicts when the Collision Avoidance (CA) alarm sounded. Aircraft X was descending through 11800 and was within 5 miles of Aircraft Y on a converging course. I broadcasted to Aircraft X to stop descent and climb immediately to 12000 FT and issued the traffic (Aircraft Y). Aircraft X was on frequency; responded and complied. Recommendation; comply with the SOP and 7110.65. Transfer communication prior to entering the receiving Controller's airspace.

Data retrieved from NASA's ASRS site as of April 2012 and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.

Nct controllers described a loss of separation event when late night airspace configurations were not clearly understood leading to confused coordination and the error.