Narrative:

Dtw departure cleared us to 8000' on a heading of 150 degrees. ATC advised light VFR traffic at 12 O'clock and 10 mi at 8500'. We did not have this traffic visually, but soon picked it up on TCAS. ATC turned us to 120 degrees to avoid the traffic. During the turn we lost contact on our TCAS briefly, but shortly after rollout the target reappeared, and the TCAS gave us a mandatory compliance RA. TCAS commanded 'descend, descend,' as the indicator advised a rate greater than 2000 FPM showing the target 300' above us at 3 O'clock we searched for traffic while descending for approximately 700'. At that point the light aircraft was spotted by the copilot (me) passing 4 O'clock about 1/2 mi latitude. The frequency was busy at this point as we tried to notify ATC of our altitude clearance deviation, but the controller soon noticed our mode C readout and queried us. After short discussion the controller told us he was aware of the traffic and that he would discuss the incident with his supervisor. He then cleared us back to 8000'. After reaching 8000' he assigned an 090 degree heading to intercept V103. After that he handed us off to ZOB. Due to the many vectors during the TCAS event and the subsequent distraction, we were momentarily playing catch-up with our VOR navigation. I was flying the aircraft while the captain checked the chart and set up my radios. It was here that a more helpful clearance such as a vector further down the road would have helped us to get back on course. Nevertheless, we should have immediately asked for a vector to buy time to set up our navigation radios. The point where we had been given a heading to intercept the arwy was within a couple of mi of a point where we were switching between 3 VOR's--from detroit to salem to carlton to fly our original clearance route. Each time we tuned in the next radio we found we were just past the point where we should have intercepted the next course. It was not a very comfortable feeling playing catch-up at 300 KTS. The ZOB controller came back and gave us a heading for slate run.

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Original NASA ASRS Text

Title: ACR WDB ALT DEVIATION IN RESPONSE TO TCASII RA. TRACK DEVIATION ALSO OCCURRED BECAUSE OF TCASII DISTR.

Narrative: DTW DEP CLRED US TO 8000' ON A HDG OF 150 DEGS. ATC ADVISED LIGHT VFR TFC AT 12 O'CLOCK AND 10 MI AT 8500'. WE DID NOT HAVE THIS TFC VISUALLY, BUT SOON PICKED IT UP ON TCAS. ATC TURNED US TO 120 DEGS TO AVOID THE TFC. DURING THE TURN WE LOST CONTACT ON OUR TCAS BRIEFLY, BUT SHORTLY AFTER ROLLOUT THE TARGET REAPPEARED, AND THE TCAS GAVE US A MANDATORY COMPLIANCE RA. TCAS COMMANDED 'DSND, DSND,' AS THE INDICATOR ADVISED A RATE GREATER THAN 2000 FPM SHOWING THE TARGET 300' ABOVE US AT 3 O'CLOCK WE SEARCHED FOR TFC WHILE DSNDING FOR APPROX 700'. AT THAT POINT THE LIGHT ACFT WAS SPOTTED BY THE COPLT (ME) PASSING 4 O'CLOCK ABOUT 1/2 MI LAT. THE FREQ WAS BUSY AT THIS POINT AS WE TRIED TO NOTIFY ATC OF OUR ALT CLRNC DEVIATION, BUT THE CTLR SOON NOTICED OUR MODE C READOUT AND QUERIED US. AFTER SHORT DISCUSSION THE CTLR TOLD US HE WAS AWARE OF THE TFC AND THAT HE WOULD DISCUSS THE INCIDENT WITH HIS SUPVR. HE THEN CLRED US BACK TO 8000'. AFTER REACHING 8000' HE ASSIGNED AN 090 DEG HDG TO INTERCEPT V103. AFTER THAT HE HANDED US OFF TO ZOB. DUE TO THE MANY VECTORS DURING THE TCAS EVENT AND THE SUBSEQUENT DISTR, WE WERE MOMENTARILY PLAYING CATCH-UP WITH OUR VOR NAV. I WAS FLYING THE ACFT WHILE THE CAPT CHKED THE CHART AND SET UP MY RADIOS. IT WAS HERE THAT A MORE HELPFUL CLRNC SUCH AS A VECTOR FURTHER DOWN THE ROAD WOULD HAVE HELPED US TO GET BACK ON COURSE. NEVERTHELESS, WE SHOULD HAVE IMMEDIATELY ASKED FOR A VECTOR TO BUY TIME TO SET UP OUR NAV RADIOS. THE POINT WHERE WE HAD BEEN GIVEN A HDG TO INTERCEPT THE ARWY WAS WITHIN A COUPLE OF MI OF A POINT WHERE WE WERE SWITCHING BTWN 3 VOR'S--FROM DETROIT TO SALEM TO CARLTON TO FLY OUR ORIGINAL CLRNC RTE. EACH TIME WE TUNED IN THE NEXT RADIO WE FOUND WE WERE JUST PAST THE POINT WHERE WE SHOULD HAVE INTERCEPTED THE NEXT COURSE. IT WAS NOT A VERY COMFORTABLE FEELING PLAYING CATCH-UP AT 300 KTS. THE ZOB CTLR CAME BACK AND GAVE US A HDG FOR SLATE RUN.

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.