Narrative:

Following the clearance for a visual approach; backed up with an ILS to runuway xxl; we received a TCAS TA below 10;000 ft MSL without any prior warning from approach control. As the pilot not flying I announced; 'traffic alert 2 o'clock; traffic in sight' and the controller responded it was an aircraft with a clearance for the visual approach to runway xxr. There was no admonition to maintain visual separation and the controller's tone gave no indication his sequencing could potentially generate any further traffic conflict. The aircraft was above our altitude and we were descending on centerline and glideslope to the FAF. Passing approximately 7;200 ft MSL; we received a TCAS 'descend' RA. The company aircraft was 300 ft [above] and slightly ahead of us when the RA warning initiated. The pilot flying disengaged the autopilot [and] auto-throttles and began a descent below the glideslope; achieving a vertical separation of 600 ft. However; after approximately ten seconds of red RA 600 ft [above]; it was obvious the traffic was not aiding vertical separation. Consequently; we corrected to the glideslope after the RA became inhibited below 900 ft AGL and continued the approach; landing uneventfully. At all times; we had the company aircraft in sight. Our response to this 'descend' RA was intentionally weak due to not wanting to get dangerously below glideslope and having no desire to trigger an egpws warning. The tower was not informed of the RA event by us or the other aircraft.it was later determined the other aircraft received a 'monitor vertical speed' RA at the time we received our 'descend' RA; which explains why they did not go around. From a crew perspective; it is apparent [that] approach control does not believe they are often setting the stage for many of these TCAS RA events. Our recommendation would be to determine a way to mitigate future events by having a conference with the controllers. Another thought is to implement a new crew procedure similar to the one used for runways 28L/right in sfo; to position the transponder in TA at eight miles.

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Original NASA ASRS Text

Title: B737 Captain reports TCAS RA during visual approach to Runway XXL; generated by an aircraft on the visual to XXR. Initial attempts to comply with the RA are abandoned when the RA becomes inhibited at 900 FT AGL and a normal landing ensues.

Narrative: Following the clearance for a visual approach; backed up with an ILS to Runuway XXL; we received a TCAS TA below 10;000 FT MSL without any prior warning from Approach Control. As the pilot not flying I announced; 'Traffic alert 2 o'clock; traffic in sight' and the Controller responded it was an aircraft with a clearance for the visual approach to Runway XXR. There was no admonition to maintain visual separation and the Controller's tone gave no indication his sequencing could potentially generate any further traffic conflict. The aircraft was above our altitude and we were descending on centerline and glideslope to the FAF. Passing approximately 7;200 FT MSL; we received a TCAS 'descend' RA. The company aircraft was 300 FT [above] and slightly ahead of us when the RA warning initiated. The pilot flying disengaged the autopilot [and] auto-throttles and began a descent below the glideslope; achieving a vertical separation of 600 FT. However; after approximately ten seconds of red RA 600 FT [above]; it was obvious the traffic was not aiding vertical separation. Consequently; we corrected to the glideslope after the RA became inhibited below 900 FT AGL and continued the approach; landing uneventfully. At all times; we had the company aircraft in sight. Our response to this 'descend' RA was intentionally weak due to not wanting to get dangerously below glideslope and having no desire to trigger an EGPWS warning. The Tower was not informed of the RA event by us or the other aircraft.It was later determined the other aircraft received a 'monitor vertical speed' RA at the time we received our 'descend' RA; which explains why they did not go around. From a crew perspective; it is apparent [that] Approach Control does not believe they are often setting the stage for many of these TCAS RA events. Our recommendation would be to determine a way to mitigate future events by having a conference with the Controllers. Another thought is to implement a new crew procedure similar to the one used for Runways 28L/R in SFO; to position the transponder in TA at eight miles.

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.