ZLA controller described a TCAS conflict event reported by a lax air carrier arrival; traffic was is...

Narrative:

I was at ZLA R13. There were strong winds from the northwest requiring lax arrivals to cross symon at 12;000 ft and 250 KTS. Due to this restriction lax arrivals were lower that usual. A C340 checked on my frequency from zuma heading northwest; VFR at 12;500 ft. I issued him the bfl altimeter. I issued traffic to the C340; a heavy B777 descending via fim for lax. The C340 was indicating 12;300 ft and the B777 was indicating 14;700 ft and approximately 10 miles. The C340 said he was looking for the traffic. I instructed the C340 to turn 10 degrees right for the traffic. The C340 informed me that he had the traffic in sight; leading me to believe it was no factor. At the same time an aircraft called; which because of the difficult accent; I thought was the B777 checking in. I issued a clearance to the B777 to cross symon and then issued a frequency change. When the B777 informed me of the TCAS alert two aircraft transmitted at once. I reissued the frequency change to the B777; the pilot then then informed me they were filing a near midair on the ground. The B777 was descending into zuma's airspace with multiple targets for lax. I acknowledged and reissued the frequency change again. I immediately informed the supervisor of the incident.

Original NASA ASRS Text

Title: ZLA Controller described a TCAS conflict event reported by a LAX Air Carrier arrival; traffic was issued and sighted by the suspected conflicting aircraft.

Narrative: I was at ZLA R13. There were strong winds from the northwest requiring LAX arrivals to cross SYMON at 12;000 FT and 250 KTS. Due to this restriction LAX arrivals were lower that usual. A C340 checked on my frequency from ZUMA heading northwest; VFR at 12;500 FT. I issued him the BFL altimeter. I issued traffic to the C340; a heavy B777 descending via FIM for LAX. The C340 was indicating 12;300 FT and the B777 was indicating 14;700 FT and approximately 10 miles. The C340 said he was looking for the traffic. I instructed the C340 to turn 10 degrees right for the traffic. The C340 informed me that he had the traffic in sight; leading me to believe it was no factor. At the same time an aircraft called; which because of the difficult accent; I thought was the B777 checking in. I issued a clearance to the B777 to cross SYMON and then issued a frequency change. When the B777 informed me of the TCAS alert two aircraft transmitted at once. I reissued the frequency change to the B777; the pilot then then informed me they were filing a near midair on the ground. The B777 was descending into ZUMA's airspace with multiple targets for LAX. I acknowledged and reissued the frequency change again. I immediately informed the Supervisor of the incident.

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.

Attributes
ACN	921330
Time
Date	201011
Local Time Of Day	0001-0600
Place
Locale Reference	ZLA.ARTCC
State Reference	CA
Aircraft 1
Make Model Name	B777 Undifferentiated or Other Model
Operating Under FAR Part	Part 121
Flight Phase	Descent
Flight Plan	IFR
Aircraft 2
Make Model Name	Cessna 340/340A
Flight Phase	Cruise
Route In Use	Vectors
Flight Plan	VFR
Person 1
Function	Enroute
Qualification	Air Traffic Control Fully Certified
Events
Anomaly	ATC Issue All Types Conflict Airborne Conflict

ZLA controller described a TCAS conflict event reported by a lax air carrier arrival; traffic was issued and sighted by the suspected conflicting aircraft.