Narrative:

Took off on runway 9 at bos with a straight out climb as per the SID. At 1500 ft, TCASII sounded an RA, first 'reduce climb' then 'descend.' a TCASII target was observed at 10 O'clock and 2-3 mi plus 200 ft and converging rapidly. Target passed above us then disappeared from scope. As climb was resumed a second RA was sounded. Target was again observed at 10 O'clock plus 200 ft but at 7 mi range. Target followed a similar path and crossed above us at plus 200 ft then disappeared. At no time was any visual contact made nor did ATC observe traffic on radar.

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Original NASA ASRS Text

Title: WDB HAS TCASII RA FOR TARGETS NOT APPEARING ON RADAR.

Narrative: TOOK OFF ON RWY 9 AT BOS WITH A STRAIGHT OUT CLB AS PER THE SID. AT 1500 FT, TCASII SOUNDED AN RA, FIRST 'REDUCE CLB' THEN 'DSND.' A TCASII TARGET WAS OBSERVED AT 10 O'CLOCK AND 2-3 MI PLUS 200 FT AND CONVERGING RAPIDLY. TARGET PASSED ABOVE US THEN DISAPPEARED FROM SCOPE. AS CLB WAS RESUMED A SECOND RA WAS SOUNDED. TARGET WAS AGAIN OBSERVED AT 10 O'CLOCK PLUS 200 FT BUT AT 7 MI RANGE. TARGET FOLLOWED A SIMILAR PATH AND CROSSED ABOVE US AT PLUS 200 FT THEN DISAPPEARED. AT NO TIME WAS ANY VISUAL CONTACT MADE NOR DID ATC OBSERVE TFC ON RADAR.

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