Narrative:

We were operating out of bay bridge airport (W29) that is currently within the enhanced class B airspace. Before engine start, I called bwi approach via telephone to get our clearance and squawk code. After departure, I contacted bwi approach and flew east to exit the airspace. Radio reception was scratchy, but readable. Once clear of the airspace, I requested and received a frequency change. There were 3 souls on board, a student pilot occupying the left front seat, myself (CFI) in the right front seat, and a private pilot/instrument student in the rear seat. I had the student pilot perform maneuvers and then we did full stop lndgs on runway 33 at easton airport (esn). After the lndgs, we departed esn to the south and climbed to 2000 ft to overfly the airport (airport elevation is 74 ft MSL). I contacted bwi approach to request clearance into the enhanced class B airspace and transition back to bay bridge airport. Bwi approach acknowledged radar contact and we proceeded toward W29. We were still outside the enhanced class B airspace when approach called traffic at our 2 O'clock position. I responded that we had the traffic in sight. The only visual clue of traffic was his landing lights (type of aircraft was unknown to us). I turned on our landing light, which was on the left wing, opposite the incoming traffic. I heard the controller talk to the incoming traffic, but did not hear any response to the calls. I thought I heard the controller say, 'if you hear me' to the traffic. This made me wonder if the incoming traffic had been with bwi, but changed frequency as he approached esn. The traffic seemed to turn toward us and approached at a high rate. The controller said, 'somebody better climb.' my first thought was, what happens if we both climb? I transmitted that we were climbing and initiated a steep climb. The bizjet passed about 500 ft below us, without any course deviation. Usually I will turn to the tail of crossing traffic, but the convergence rate was too high. After the jet passed below us the controller thanked us and told us to descend to 2000 ft and proceed to W29. One contributing factor was the controller saying, 'somebody better climb.' I know that once we confirm that we have the traffic in sight, it is our responsibility to see-and-avoid. There was very little time for us to respond. If the controller told us (by n-number) to climb, there would have been no hesitation or second thoughts about what happens if both of us climb. Another factor was the scratchy reception. It may have been due to the portable intercom system. I flew with the private pilot/instrument student later that evening. We didn't use the portable intercom and the radio reception was much clrer.

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Original NASA ASRS Text

Title: C172 INSTRUCTOR RETURNING TO LAND IS ALERTED BY BWI CTLR OF TFC CONFLICT.

Narrative: WE WERE OPERATING OUT OF BAY BRIDGE ARPT (W29) THAT IS CURRENTLY WITHIN THE ENHANCED CLASS B AIRSPACE. BEFORE ENG START, I CALLED BWI APCH VIA TELEPHONE TO GET OUR CLRNC AND SQUAWK CODE. AFTER DEP, I CONTACTED BWI APCH AND FLEW E TO EXIT THE AIRSPACE. RADIO RECEPTION WAS SCRATCHY, BUT READABLE. ONCE CLR OF THE AIRSPACE, I REQUESTED AND RECEIVED A FREQ CHANGE. THERE WERE 3 SOULS ON BOARD, A STUDENT PLT OCCUPYING THE L FRONT SEAT, MYSELF (CFI) IN THE R FRONT SEAT, AND A PVT PLT/INST STUDENT IN THE REAR SEAT. I HAD THE STUDENT PLT PERFORM MANEUVERS AND THEN WE DID FULL STOP LNDGS ON RWY 33 AT EASTON ARPT (ESN). AFTER THE LNDGS, WE DEPARTED ESN TO THE S AND CLBED TO 2000 FT TO OVERFLY THE ARPT (ARPT ELEVATION IS 74 FT MSL). I CONTACTED BWI APCH TO REQUEST CLRNC INTO THE ENHANCED CLASS B AIRSPACE AND TRANSITION BACK TO BAY BRIDGE ARPT. BWI APCH ACKNOWLEDGED RADAR CONTACT AND WE PROCEEDED TOWARD W29. WE WERE STILL OUTSIDE THE ENHANCED CLASS B AIRSPACE WHEN APCH CALLED TFC AT OUR 2 O'CLOCK POS. I RESPONDED THAT WE HAD THE TFC IN SIGHT. THE ONLY VISUAL CLUE OF TFC WAS HIS LNDG LIGHTS (TYPE OF ACFT WAS UNKNOWN TO US). I TURNED ON OUR LNDG LIGHT, WHICH WAS ON THE L WING, OPPOSITE THE INCOMING TFC. I HEARD THE CTLR TALK TO THE INCOMING TFC, BUT DID NOT HEAR ANY RESPONSE TO THE CALLS. I THOUGHT I HEARD THE CTLR SAY, 'IF YOU HEAR ME' TO THE TFC. THIS MADE ME WONDER IF THE INCOMING TFC HAD BEEN WITH BWI, BUT CHANGED FREQ AS HE APCHED ESN. THE TFC SEEMED TO TURN TOWARD US AND APCHED AT A HIGH RATE. THE CTLR SAID, 'SOMEBODY BETTER CLB.' MY FIRST THOUGHT WAS, WHAT HAPPENS IF WE BOTH CLB? I XMITTED THAT WE WERE CLBING AND INITIATED A STEEP CLB. THE BIZJET PASSED ABOUT 500 FT BELOW US, WITHOUT ANY COURSE DEV. USUALLY I WILL TURN TO THE TAIL OF XING TFC, BUT THE CONVERGENCE RATE WAS TOO HIGH. AFTER THE JET PASSED BELOW US THE CTLR THANKED US AND TOLD US TO DSND TO 2000 FT AND PROCEED TO W29. ONE CONTRIBUTING FACTOR WAS THE CTLR SAYING, 'SOMEBODY BETTER CLB.' I KNOW THAT ONCE WE CONFIRM THAT WE HAVE THE TFC IN SIGHT, IT IS OUR RESPONSIBILITY TO SEE-AND-AVOID. THERE WAS VERY LITTLE TIME FOR US TO RESPOND. IF THE CTLR TOLD US (BY N-NUMBER) TO CLB, THERE WOULD HAVE BEEN NO HESITATION OR SECOND THOUGHTS ABOUT WHAT HAPPENS IF BOTH OF US CLB. ANOTHER FACTOR WAS THE SCRATCHY RECEPTION. IT MAY HAVE BEEN DUE TO THE PORTABLE INTERCOM SYS. I FLEW WITH THE PVT PLT/INST STUDENT LATER THAT EVENING. WE DIDN'T USE THE PORTABLE INTERCOM AND THE RADIO RECEPTION WAS MUCH CLRER.

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.