B737-700 captain experiences a near midair collision with a light aircraft at 8;000 feet near gilro....

Narrative:

We were on the hyp 5 STAR to sjc. At 8;000 feet MSL and two NM prior to gilro; norcal issued clearance direct klide. ATC called out traffic that was observed at 8;500 feet MSL. Flight crew did not visually see traffic. ATC issued a 30 degree left turn to avoid traffic but then cancelled that clearance and issued a descent clearance to 6;500 feet MSL. We received a TCAS RA with contact +400 and a RA descend command. TCAS traffic was visually acquired by flight crew (GA low-wing prop with red/white paint scheme). We were in a descent while performing a 5 to 10 degree right turn. Conflicting traffic was observed descending as well and turning slightly left to keep aligned with our course. Conflicting aircraft passed directly overhead +400 from our aircraft traveling the opposite direction. Increase FAA education of pilots in the norcal area. Highlight high density arrival corridors; proper communication procedures; discuss benefits of VFR flight following; and review proper procedures for a TCAS RA event.

Original NASA ASRS Text

Title: B737-700 Captain experiences a NMAC with a light aircraft at 8;000 feet near GILRO. TCAS issued a descend RA and the Captain believes that the intruder was also descending. Both aircraft maneuvered to fly reciprocal courses.

Narrative: We were on the HYP 5 STAR to SJC. At 8;000 feet MSL and two NM prior to GILRO; NorCal issued clearance direct KLIDE. ATC called out traffic that was observed at 8;500 feet MSL. Flight crew did not visually see traffic. ATC issued a 30 degree left turn to avoid traffic but then cancelled that clearance and issued a descent clearance to 6;500 feet MSL. We received a TCAS RA with contact +400 and a RA descend command. TCAS traffic was visually acquired by flight crew (GA low-wing prop with red/white paint scheme). We were in a descent while performing a 5 to 10 degree right turn. Conflicting traffic was observed descending as well and turning slightly left to keep aligned with our course. Conflicting aircraft passed directly overhead +400 from our aircraft traveling the opposite direction. Increase FAA education of pilots in the NorCal area. Highlight high density arrival corridors; proper communication procedures; discuss benefits of VFR flight following; and review proper procedures for a TCAS RA event.

Data retrieved from NASA's ASRS site 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	1174533
Time
Date	201405
Local Time Of Day	1201-1800
Place
Locale Reference	NCT.TRACON
State Reference	CA
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Make Model Name	B737-700
Operating Under FAR Part	Part 121
Flight Phase	Descent
Route In Use	STAR HYP 5
Flight Plan	IFR
Aircraft 2
Make Model Name	Small Aircraft
Person 1
Function	Captain
Qualification	Flight Crew Air Transport Pilot (ATP)
Experience	Flight Crew Last 90 Days 275
Events
Anomaly	ATC Issue All Types Conflict NMAC
Miss Distance	Horizontal 0 Vertical 400

B737-700 captain experiences a near midair collision with a light aircraft at 8;000 feet near gilro. TCAS issued a descend RA and the captain believes that the intruder was also descending. Both aircraft maneuvered to fly reciprocal courses.