Narrative:

Potomac departure gave us a heading of 040 degrees and altitude of 7000 ft MSL. After the turn; I noticed a target on the TCAS at 3 O'clock position; low and climbing. We received a TA and a few seconds later an RA. Initially the RA was 'traffic; traffic; descend; descend' immediately followed by 'climb; climb; increase climb.' the PF followed the TCAS commands as I backed him up. We descended about 300 ft and then climbed about 500-600 ft. We were IMC and never made visual on the other aircraft. I think the other aircraft was a learjet that had departed right behind us. I noticed that ATC had turned them inside of us. However; I thought the learjet was cleared to 5000 ft only. I'm not certain of that fact; but I did hear the controller give some aircraft a phone number to call upon arrival at destination. I think the TCAS gave us a 'descend' and then a 'climb' because the aircraft was climbing to our altitude of 7000 ft but then leveled off at 7000 ft while we were responding to the RA. We followed our TCAS and dodged a bullet.

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Original NASA ASRS Text

Title: GLF4 FLT CREW RECEIVED TCAS RA AT 7000 FT DURING CLBOUT FROM IAD; APPARENTLY CAUSED BY SUCCEEDING LEARJET DEP ACFT.

Narrative: POTOMAC DEP GAVE US A HDG OF 040 DEGS AND ALT OF 7000 FT MSL. AFTER THE TURN; I NOTICED A TARGET ON THE TCAS AT 3 O'CLOCK POS; LOW AND CLBING. WE RECEIVED A TA AND A FEW SECONDS LATER AN RA. INITIALLY THE RA WAS 'TFC; TFC; DSND; DSND' IMMEDIATELY FOLLOWED BY 'CLB; CLB; INCREASE CLB.' THE PF FOLLOWED THE TCAS COMMANDS AS I BACKED HIM UP. WE DSNDED ABOUT 300 FT AND THEN CLBED ABOUT 500-600 FT. WE WERE IMC AND NEVER MADE VISUAL ON THE OTHER ACFT. I THINK THE OTHER ACFT WAS A LEARJET THAT HAD DEPARTED RIGHT BEHIND US. I NOTICED THAT ATC HAD TURNED THEM INSIDE OF US. HOWEVER; I THOUGHT THE LEARJET WAS CLRED TO 5000 FT ONLY. I'M NOT CERTAIN OF THAT FACT; BUT I DID HEAR THE CTLR GIVE SOME ACFT A PHONE NUMBER TO CALL UPON ARR AT DEST. I THINK THE TCAS GAVE US A 'DSND' AND THEN A 'CLB' BECAUSE THE ACFT WAS CLBING TO OUR ALT OF 7000 FT BUT THEN LEVELED OFF AT 7000 FT WHILE WE WERE RESPONDING TO THE RA. WE FOLLOWED OUR TCAS AND DODGED A BULLET.

Data retrieved from NASA's ASRS site as of January 2009 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.