Narrative:

Our ATC clearance was as follows: 'depart northwest on the dca 328 degree radial, radar vectors to aml, as filed. Maintain 5000 ft....' this is a standard IFR departure clearance at dca. We (flight crew) agreed that runway 1 would be our departure runway based on WX conditions. Dca tower issued us a clearance to taxi into position and hold runway 1. Tower controller stated, 'traffic on a 4 mi final, be ready for an immediate takeoff.' we responded that we were ready. As soon as we taxied into position, we were given clearance for takeoff. After the final before takeoff items were accomplished (approximately 2-3 seconds), the first officer assumed duty as PF and captain as PNF. During rotation and liftoff, we heard traffic announce a missed approach. We lifted off and were IMC no later than 300 ft MSL. PF turned to intercept the dca 328 degree radial and continued normal departure procedures. The tower controller quickly issued us amended departure instructions of a left turn to 270 degrees and maintain 1500 ft. While commencing the left turn, PNF was setting altitude selector to new altitude when 'traffic' was announced by TCASII. We then saw an amber target appear on the bottom left corner of the mfd screen. TCASII range was set to 2.5 NM and we only received a TA. The traffic was observed on the mfd at +400 ft vertical separation and moving towards us very rapidly. We complied with ATC's instructions and tried to maintain separation. The other traffic's flight path was unknown, but seemed to proceed from behind and above us to below and to the right of our aircraft. We were climbing so the other aircraft was not necessarily descending, but rather in a shallow climb or level flight. The aircraft was a small jet, either an emb-135 or 145 based on the air carrier operating the flight. During incident, PNF tried to acquire a visual on the traffic but was unsuccessful. The intruder aircraft passed our aircraft (the white silhouette on mfd) at -100 ft below our altitude within an estimated 1/4 mi horizontal distance or less. Flight continued on without incident. After writing the above narrative, I spoke with the dca tower supervisor. She informed me of a few things that I think cleared up the incident and would qualify as contributing factors. Additionally, I had several other thoughts on the incident: 1) she said the other aircraft started at an altitude below ours (or, in relation to) and then climbed above us and then ended up passing below us. This sounds correct but I am not sure at which point our TCASII activated (ie, other aircraft's physical location) so I believe my initial perception above is correct. This incident did, however, take place very quickly so I am willing to accept that the traffic took a slightly different vertical profile before passing under us. 2) she said the aircraft on ILS runway 1 performed missed approach prior to reaching minimums, accelerating their closure rate. 3) she said the aircraft on ILS runway 1 turned prior to missed approach point and effectively cut-the-corner on their procedure and our separation. 4) she said aircraft on final were registering ground speeds over 50 KTS faster than normal, implying a very large tailwind aloft. 5) she stated that when our aircraft was given clearance to depart, the traffic was 2.5 mi out. We were told 4 mi when given position-and-hold and then 3 mi as were beginning takeoff roll. 6) our aircraft was loaded to within 100 pounds of the maximum structural takeoff weight and in the initial climb phase of flight. The airspeed was low but accelerating, the altitude was low and increasing so our choices for evading traffic are limited. We rely on not only TCASII but ATC to issue us instructions in IMC to keep clear of others. 7) our operations prohibit us from responding to only a TA while IMC without traffic in sight. The idea is not to cause other traffic conflicts or hazardous sits with minimal data. Example: aircraft climbing rapidly towards you and below may cause a TA, but not an RA if it does not intrude on our TCASII-protected airspace. The low altitude of this incident caused TCASII to only issue a TA. We responded the best we could given this limited information, being IMC, and not wanting to get in dangerous proximity of any of the following: other aircraft, prohibited areas, ground or nearby buildings. In my experience with the dornier 328, I have witnessed false TA's and targets appearing quickly and without warning so TCASII is useful but not a sole means to avoid traffic. In this particular incident, TCASII was essential to the safety of flight when paired with the quick-thinking instructions of the tower controller. It's hard to say that if the other pilot first proceeded to the missed approach point before turning and if our separation at the time of takeoff actually was 3-4 mi instead of 2.5 mi, this incident would not have occurred. Separation at dca is typically less than other high volume airports and a takeoff clearance with the stated separation is not unusual. ATC should, however, use the ground speed readout of aircraft on final before issuing a takeoff clearance taking into consideration a potentially-heavy tailwind and they should state separation accurately to flight crews.

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Original NASA ASRS Text

Title: D328 DEPARTING FROM DCA AT 400 FT CLBING HAS NMAC WITH ACFT ON MISSED APCH PROC.

Narrative: OUR ATC CLRNC WAS AS FOLLOWS: 'DEPART NW ON THE DCA 328 DEG RADIAL, RADAR VECTORS TO AML, AS FILED. MAINTAIN 5000 FT....' THIS IS A STANDARD IFR DEP CLRNC AT DCA. WE (FLT CREW) AGREED THAT RWY 1 WOULD BE OUR DEP RWY BASED ON WX CONDITIONS. DCA TWR ISSUED US A CLRNC TO TAXI INTO POS AND HOLD RWY 1. TWR CTLR STATED, 'TFC ON A 4 MI FINAL, BE READY FOR AN IMMEDIATE TKOF.' WE RESPONDED THAT WE WERE READY. AS SOON AS WE TAXIED INTO POS, WE WERE GIVEN CLRNC FOR TKOF. AFTER THE FINAL BEFORE TKOF ITEMS WERE ACCOMPLISHED (APPROX 2-3 SECONDS), THE FO ASSUMED DUTY AS PF AND CAPT AS PNF. DURING ROTATION AND LIFTOFF, WE HEARD TFC ANNOUNCE A MISSED APCH. WE LIFTED OFF AND WERE IMC NO LATER THAN 300 FT MSL. PF TURNED TO INTERCEPT THE DCA 328 DEG RADIAL AND CONTINUED NORMAL DEP PROCS. THE TWR CTLR QUICKLY ISSUED US AMENDED DEP INSTRUCTIONS OF A L TURN TO 270 DEGS AND MAINTAIN 1500 FT. WHILE COMMENCING THE L TURN, PNF WAS SETTING ALT SELECTOR TO NEW ALT WHEN 'TFC' WAS ANNOUNCED BY TCASII. WE THEN SAW AN AMBER TARGET APPEAR ON THE BOTTOM L CORNER OF THE MFD SCREEN. TCASII RANGE WAS SET TO 2.5 NM AND WE ONLY RECEIVED A TA. THE TFC WAS OBSERVED ON THE MFD AT +400 FT VERT SEPARATION AND MOVING TOWARDS US VERY RAPIDLY. WE COMPLIED WITH ATC'S INSTRUCTIONS AND TRIED TO MAINTAIN SEPARATION. THE OTHER TFC'S FLT PATH WAS UNKNOWN, BUT SEEMED TO PROCEED FROM BEHIND AND ABOVE US TO BELOW AND TO THE R OF OUR ACFT. WE WERE CLBING SO THE OTHER ACFT WAS NOT NECESSARILY DSNDING, BUT RATHER IN A SHALLOW CLB OR LEVEL FLT. THE ACFT WAS A SMALL JET, EITHER AN EMB-135 OR 145 BASED ON THE ACR OPERATING THE FLT. DURING INCIDENT, PNF TRIED TO ACQUIRE A VISUAL ON THE TFC BUT WAS UNSUCCESSFUL. THE INTRUDER ACFT PASSED OUR ACFT (THE WHITE SILHOUETTE ON MFD) AT -100 FT BELOW OUR ALT WITHIN AN ESTIMATED 1/4 MI HORIZ DISTANCE OR LESS. FLT CONTINUED ON WITHOUT INCIDENT. AFTER WRITING THE ABOVE NARRATIVE, I SPOKE WITH THE DCA TWR SUPVR. SHE INFORMED ME OF A FEW THINGS THAT I THINK CLRED UP THE INCIDENT AND WOULD QUALIFY AS CONTRIBUTING FACTORS. ADDITIONALLY, I HAD SEVERAL OTHER THOUGHTS ON THE INCIDENT: 1) SHE SAID THE OTHER ACFT STARTED AT AN ALT BELOW OURS (OR, IN RELATION TO) AND THEN CLBED ABOVE US AND THEN ENDED UP PASSING BELOW US. THIS SOUNDS CORRECT BUT I AM NOT SURE AT WHICH POINT OUR TCASII ACTIVATED (IE, OTHER ACFT'S PHYSICAL LOCATION) SO I BELIEVE MY INITIAL PERCEPTION ABOVE IS CORRECT. THIS INCIDENT DID, HOWEVER, TAKE PLACE VERY QUICKLY SO I AM WILLING TO ACCEPT THAT THE TFC TOOK A SLIGHTLY DIFFERENT VERT PROFILE BEFORE PASSING UNDER US. 2) SHE SAID THE ACFT ON ILS RWY 1 PERFORMED MISSED APCH PRIOR TO REACHING MINIMUMS, ACCELERATING THEIR CLOSURE RATE. 3) SHE SAID THE ACFT ON ILS RWY 1 TURNED PRIOR TO MISSED APCH POINT AND EFFECTIVELY CUT-THE-CORNER ON THEIR PROC AND OUR SEPARATION. 4) SHE SAID ACFT ON FINAL WERE REGISTERING GND SPDS OVER 50 KTS FASTER THAN NORMAL, IMPLYING A VERY LARGE TAILWIND ALOFT. 5) SHE STATED THAT WHEN OUR ACFT WAS GIVEN CLRNC TO DEPART, THE TFC WAS 2.5 MI OUT. WE WERE TOLD 4 MI WHEN GIVEN POS-AND-HOLD AND THEN 3 MI AS WERE BEGINNING TKOF ROLL. 6) OUR ACFT WAS LOADED TO WITHIN 100 LBS OF THE MAX STRUCTURAL TKOF WT AND IN THE INITIAL CLB PHASE OF FLT. THE AIRSPD WAS LOW BUT ACCELERATING, THE ALT WAS LOW AND INCREASING SO OUR CHOICES FOR EVADING TFC ARE LIMITED. WE RELY ON NOT ONLY TCASII BUT ATC TO ISSUE US INSTRUCTIONS IN IMC TO KEEP CLR OF OTHERS. 7) OUR OPS PROHIBIT US FROM RESPONDING TO ONLY A TA WHILE IMC WITHOUT TFC IN SIGHT. THE IDEA IS NOT TO CAUSE OTHER TFC CONFLICTS OR HAZARDOUS SITS WITH MINIMAL DATA. EXAMPLE: ACFT CLBING RAPIDLY TOWARDS YOU AND BELOW MAY CAUSE A TA, BUT NOT AN RA IF IT DOES NOT INTRUDE ON OUR TCASII-PROTECTED AIRSPACE. THE LOW ALT OF THIS INCIDENT CAUSED TCASII TO ONLY ISSUE A TA. WE RESPONDED THE BEST WE COULD GIVEN THIS LIMITED INFO, BEING IMC, AND NOT WANTING TO GET IN DANGEROUS PROX OF ANY OF THE FOLLOWING: OTHER ACFT, PROHIBITED AREAS, GND OR NEARBY BUILDINGS. IN MY EXPERIENCE WITH THE DORNIER 328, I HAVE WITNESSED FALSE TA'S AND TARGETS APPEARING QUICKLY AND WITHOUT WARNING SO TCASII IS USEFUL BUT NOT A SOLE MEANS TO AVOID TFC. IN THIS PARTICULAR INCIDENT, TCASII WAS ESSENTIAL TO THE SAFETY OF FLT WHEN PAIRED WITH THE QUICK-THINKING INSTRUCTIONS OF THE TWR CTLR. IT'S HARD TO SAY THAT IF THE OTHER PLT FIRST PROCEEDED TO THE MISSED APCH POINT BEFORE TURNING AND IF OUR SEPARATION AT THE TIME OF TKOF ACTUALLY WAS 3-4 MI INSTEAD OF 2.5 MI, THIS INCIDENT WOULD NOT HAVE OCCURRED. SEPARATION AT DCA IS TYPICALLY LESS THAN OTHER HIGH VOLUME ARPTS AND A TKOF CLRNC WITH THE STATED SEPARATION IS NOT UNUSUAL. ATC SHOULD, HOWEVER, USE THE GND SPD READOUT OF ACFT ON FINAL BEFORE ISSUING A TKOF CLRNC TAKING INTO CONSIDERATION A POTENTIALLY-HVY TAILWIND AND THEY SHOULD STATE SEPARATION ACCURATELY TO FLT CREWS.

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.