B737 flight crew reports taking evasive action for a TCAS RA during descent into bur. Clouds obscure...

Attributes
ACN	1050008
Time
Date	201211
Local Time Of Day	1201-1800
Place
Locale Reference	BUR.Airport
State Reference	CA
Environment
Flight Conditions	Mixed
Light	Daylight
Aircraft 1
Make Model Name	B737-700
Operating Under FAR Part	Part 121
Flight Phase	Descent
Route In Use	Vectors STAR LYNXX8
Flight Plan	IFR
Aircraft 2
Make Model Name	Aerobatic
Flight Plan	VFR
Person 1
Function	First Officer Pilot Not Flying
Experience	Flight Crew Last 90 Days 218
Person 2
Function	Pilot Flying Captain
Experience	Flight Crew Last 90 Days 116
Events
Anomaly	Conflict Airborne Conflict Deviation - Altitude Excursion From Assigned Altitude
Miss Distance	Horizontal 500 Vertical 200

Narrative:

While on approach to bur; I was the pilot monitoring. We were issued a heading and a decent from 6;000 feet to 5;000 feet. ATC advised traffic at one o'clock and five miles. We advised traffic was not in sight due to being in and out of IMC. ATC issued another vector and advised traffic appeared to be descending and at one mile. As we broke out of the clouds; the traffic was in front of us (moving right to left) in a rapid descending left turn. Immediately the TCAS called traffic and descend. The captain kicked off the autopilot and pitched down and turned hard right to avoid the traffic. We estimate that we came within 200 feet vertical and 500 feet horizontal from the other aircraft. We leveled off at 4;000 feet and 10-20 degrees from our assigned heading. I advised ATC that we maneuvered in response to an RA and remained at 4000 feet. We continued and landed in bur with no further issues. Hard to say what could have prevented this incident. The other aircraft was not talking to ATC and made several rapid maneuvers; apparently to avoid clouds. The TCAS system worked. We responded in a timely manner to avoid a collision.

Original NASA ASRS Text

Title: B737 flight crew reports taking evasive action for a TCAS RA during descent into BUR. Clouds obscured visual contact with the other aircraft until the first TCAS resolution had been enunciated.

Narrative: While on approach to BUR; I was the Pilot Monitoring. We were issued a heading and a decent from 6;000 feet to 5;000 feet. ATC advised traffic at one o'clock and five miles. We advised traffic was not in sight due to being in and out of IMC. ATC issued another vector and advised traffic appeared to be descending and at one mile. As we broke out of the clouds; the traffic was in front of us (moving right to left) in a rapid descending left turn. Immediately the TCAS called Traffic and Descend. The Captain kicked off the autopilot and pitched down and turned hard right to avoid the traffic. We estimate that we came within 200 feet vertical and 500 feet horizontal from the other aircraft. We leveled off at 4;000 feet and 10-20 degrees from our assigned heading. I advised ATC that we maneuvered in response to an RA and remained at 4000 feet. We continued and landed in BUR with no further issues. Hard to say what could have prevented this incident. The other aircraft was not talking to ATC and made several rapid maneuvers; apparently to avoid clouds. The TCAS system worked. We responded in a timely manner to avoid a collision.

Data retrieved from NASA's ASRS site as of July 2013 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.

B737 flight crew reports taking evasive action for a TCAS RA during descent into bur. Clouds obscured visual contact with the other aircraft until the first TCAS resolution had been enunciated.