MD80 flight crew experienced a TCAS RA for climb as they pass over a VFR aircraft 500 ft below them....

Narrative:

While descending into abq; approach cleared us to 12;000 ft. As we were descending we were advised of VFR traffic at our 10 to 11 o'clock position at 11;500 ft. Fist officer was leveling at 12;000 ft when we saw the traffic and got an advisory on the TCAS. The traffic (a cessna crusader; I believe) was in the left bank going from 10 o'clock to 9 o'clock and coming in right underneath us. The TCAS went from an advisory to an RA and first officer initiated a climb into the green band on the vsi. We climbed to 12;200 ft before getting a 'clear of conflict' from TCAS. Our traffic had overshot his altitude and as he went beneath us I saw 400 ft vertical separation on the TCAS. We told abq approach that we were responding to an RA and they acknowledged. Our deviation caused no conflict with any other aircraft.

Original NASA ASRS Text

Title: MD80 flight crew experienced a TCAS RA for climb as they pass over a VFR aircraft 500 FT below them. The VFR pilot was not maintaining altitude precisely (climb) which triggered the RA.

Narrative: While descending into ABQ; approach cleared us to 12;000 FT. As we were descending we were advised of VFR traffic at our 10 to 11 o'clock position at 11;500 FT. Fist Officer was leveling at 12;000 FT when we saw the traffic and got an advisory on the TCAS. The traffic (a Cessna Crusader; I believe) was in the left bank going from 10 o'clock to 9 o'clock and coming in right underneath us. The TCAS went from an advisory to an RA and First Officer initiated a climb into the green band on the VSI. We climbed to 12;200 FT before getting a 'clear of conflict' from TCAS. Our traffic had overshot his altitude and as he went beneath us I saw 400 FT vertical separation on the TCAS. We told ABQ Approach that we were responding to an RA and they acknowledged. Our deviation caused no conflict with any other aircraft.

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	853338
Time
Date	200909
Local Time Of Day	0601-1200
Place
Locale Reference	ABQ.Airport
State Reference	NM
Environment
Light	Daylight
Aircraft 1
Make Model Name	MD-80 Series (DC-9-80) Undifferentiated or Other Model
Operating Under FAR Part	Part 121
Flight Phase	Initial Approach
Flight Plan	IFR
Person 1
Function	Captain Pilot Not Flying
Person 2
Function	Pilot Flying First Officer
Events
Anomaly	Conflict NMAC
Miss Distance	Horizontal 0 Vertical 400

MD80 flight crew experienced a TCAS RA for climb as they pass over a VFR aircraft 500 ft below them. The VFR pilot was not maintaining altitude precisely (climb) which triggered the RA.