Narrative:

On the cruise climb; ATC informed us that there was traffic in the vicinity at 8;500 feet; travelling southwest. We kept a good lookout; but did not have visual with the traffic as it was hazy. The TCAS did not display a diamond on the mfd (multi-functional display) for reference to the traffic. Suddenly; reaching about 7;700 feet; the TCAS said; 'traffic! Descend!' this action was undertaken very promptly; and we flew under the traffic with less than 300 feet separation. ATC was advised of the deviation as it was done. It was a single engine; flying under VFR and not on the same frequency. Once clear of the conflict; ATC cleared us to continue as previously cleared; and we returned to the climb. The TCAS gave a resolution advisory and showed on the ivsi that a descent rate in excess of 2;000 feet per minute was required to avoid the traffic. ATC informed us of the traffic twice; but did not offer any way to avoid it; like a vector; or tell us to climb faster or pause the climb. In addition; the sky was very hazy at our altitude; making it hard to see anything horizontally. I reduced the power quickly; and immediately transitioned from a 5 degree nose up climb into a 5 degree nose down descent; giving a rate of descent of 3;000 feet per minute. ATC could have been more helpful; as we did inform them that we could not see very well.

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Original NASA ASRS Text

Title: A light transport aircraft First Officer reported a NMAC with a VFR single engine aircraft which ATC reported level at 8;500 FT. The crew responded to a TCAS RA but ATC did not give vectors away from the conflicting traffic.

Narrative: On the cruise climb; ATC informed us that there was traffic in the vicinity at 8;500 feet; travelling southwest. We kept a good lookout; but did not have visual with the traffic as it was hazy. The TCAS did not display a diamond on the MFD (multi-functional display) for reference to the traffic. Suddenly; reaching about 7;700 feet; the TCAS said; 'Traffic! Descend!' This action was undertaken very promptly; and we flew under the traffic with less than 300 feet separation. ATC was advised of the deviation as it was done. It was a single engine; flying under VFR and not on the same frequency. Once clear of the conflict; ATC cleared us to continue as previously cleared; and we returned to the climb. The TCAS gave a resolution advisory and showed on the IVSI that a descent rate in excess of 2;000 feet per minute was required to avoid the traffic. ATC informed us of the traffic twice; but did not offer any way to avoid it; like a vector; or tell us to climb faster or pause the climb. In addition; the sky was very hazy at our altitude; making it hard to see anything horizontally. I reduced the power quickly; and immediately transitioned from a 5 degree nose up climb into a 5 degree nose down descent; giving a rate of descent of 3;000 feet per minute. ATC could have been more helpful; as we did inform them that we could not see very well.

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.