Narrative:

Company and FAA have agreed that any deviation while responding to a resolution alert while flying a TCAS equipped aircraft is permissible and will not subject the pilot to violation. We were flying an medium large transport with the TCAS in use. Cockpit crew consisted of my first officer, myself, plus a TCAS project pilot observer. While approaching our cleared altitude, 3000', and entering a downwind leg, heading 160 degrees, we received a traffic advisory which required no response. Shortly thereafter, after being cleared for a visual approach with flaps 2 degrees and at about 200 KTS, the TCAS gave us a resolution advisory a/V warning to climb at 1500 FPM. In accordance with TCAS training and the TCAS bulletin, we initiated a climb of 1500 FPM within 1-2 seconds. While in this climb, the RA ceased. The maneuver carried us to 3700'. We advised ATC of our deviation, and then completed the visual approach and landing west/O further event. We never saw any traffic conflict visually, nor had ATC warned us of any traffic conflict. We surmise that the resolution advisory was caused by a transponder equipped commuter plane that had just taken off from smf and had turned toward us on a 300 degree assigned heading as we were passing overhead. Once on the ground, the TCAS project pilot discussed this incident with sac TRACON. The TCAS project pilot explained that the entire episode was handled totally within the guidelines of the TCAS bulletin and air carrier training.

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Original NASA ASRS Text

Title: ACR MLG ALT DEVIATION EXCURSION FROM CLRNC ALT IN RESPONSE TO TCAS RESOLUTION ALERT.

Narrative: COMPANY AND FAA HAVE AGREED THAT ANY DEVIATION WHILE RESPONDING TO A RESOLUTION ALERT WHILE FLYING A TCAS EQUIPPED ACFT IS PERMISSIBLE AND WILL NOT SUBJECT THE PLT TO VIOLATION. WE WERE FLYING AN MLG WITH THE TCAS IN USE. COCKPIT CREW CONSISTED OF MY F/O, MYSELF, PLUS A TCAS PROJECT PLT OBSERVER. WHILE APCHING OUR CLRED ALT, 3000', AND ENTERING A DOWNWIND LEG, HDG 160 DEGS, WE RECEIVED A TFC ADVISORY WHICH REQUIRED NO RESPONSE. SHORTLY THEREAFTER, AFTER BEING CLRED FOR A VISUAL APCH WITH FLAPS 2 DEGS AND AT ABOUT 200 KTS, THE TCAS GAVE US A RESOLUTION ADVISORY A/V WARNING TO CLB AT 1500 FPM. IN ACCORDANCE WITH TCAS TRNING AND THE TCAS BULLETIN, WE INITIATED A CLB OF 1500 FPM WITHIN 1-2 SECS. WHILE IN THIS CLB, THE RA CEASED. THE MANEUVER CARRIED US TO 3700'. WE ADVISED ATC OF OUR DEVIATION, AND THEN COMPLETED THE VISUAL APCH AND LNDG W/O FURTHER EVENT. WE NEVER SAW ANY TFC CONFLICT VISUALLY, NOR HAD ATC WARNED US OF ANY TFC CONFLICT. WE SURMISE THAT THE RESOLUTION ADVISORY WAS CAUSED BY A TRANSPONDER EQUIPPED COMMUTER PLANE THAT HAD JUST TAKEN OFF FROM SMF AND HAD TURNED TOWARD US ON A 300 DEG ASSIGNED HDG AS WE WERE PASSING OVERHEAD. ONCE ON THE GND, THE TCAS PROJECT PLT DISCUSSED THIS INCIDENT WITH SAC TRACON. THE TCAS PROJECT PLT EXPLAINED THAT THE ENTIRE EPISODE WAS HANDLED TOTALLY WITHIN THE GUIDELINES OF THE TCAS BULLETIN AND ACR TRNING.

Data retrieved from NASA's ASRS site as of August 2007 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.