Narrative:

Cleared by dulles approach for ILS approach 26 at martinsburg via mrb VOR, transition route to FAF. After intercepting ILS final, dulles advised of VFR traffic in vicinity of airport, terminated radar service and told us to contact tower. We switched frequency immediately, but were preoccupied with landing checklist and searching for traffic and didn't call tower right away. At approximately 4 mi out, I saw a low wing single engine aircraft turning to final at about our 10 O'clock in a bank such that I don't think he saw us. He was intercepting final ahead of us (belly-up to us), so I initiated a climbing left turn to go around behind him. At this time the aircraft commander was calling the tower operator, who was very surprised by our appearance and upset that we had not called earlier. She was very right! We allowed our communication discipline to break down due to preoccupation with checklists and discussing of the traffic and the approach. We also assumed, wrongfully, that the tower would receive a radar handoff from dulles approach. The meaning of 'radar service terminated' had not sunk into our consciousness. Our subsequent discussion of this incident has served as a good review of communications at CTAF (tower) facilities.

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Original NASA ASRS Text

Title: POTENTIAL CONFLICT AFTER UNAUTH PENETRATION OF AIRSPACE BY MIL ACFT. PROX OF ATA.

Narrative: CLRED BY DULLES APCH FOR ILS APCH 26 AT MARTINSBURG VIA MRB VOR, TRANSITION RTE TO FAF. AFTER INTERCEPTING ILS FINAL, DULLES ADVISED OF VFR TFC IN VICINITY OF ARPT, TERMINATED RADAR SVC AND TOLD US TO CONTACT TWR. WE SWITCHED FREQ IMMEDIATELY, BUT WERE PREOCCUPIED WITH LNDG CHKLIST AND SEARCHING FOR TFC AND DIDN'T CALL TWR RIGHT AWAY. AT APPROX 4 MI OUT, I SAW A LOW WING SINGLE ENG ACFT TURNING TO FINAL AT ABOUT OUR 10 O'CLOCK IN A BANK SUCH THAT I DON'T THINK HE SAW US. HE WAS INTERCEPTING FINAL AHEAD OF US (BELLY-UP TO US), SO I INITIATED A CLBING L TURN TO GAR BEHIND HIM. AT THIS TIME THE ACFT COMMANDER WAS CALLING THE TWR OPERATOR, WHO WAS VERY SURPRISED BY OUR APPEARANCE AND UPSET THAT WE HAD NOT CALLED EARLIER. SHE WAS VERY RIGHT! WE ALLOWED OUR COM DISCIPLINE TO BREAK DOWN DUE TO PREOCCUPATION WITH CHKLISTS AND DISCUSSING OF THE TFC AND THE APCH. WE ALSO ASSUMED, WRONGFULLY, THAT THE TWR WOULD RECEIVE A RADAR HDOF FROM DULLES APCH. THE MEANING OF 'RADAR SVC TERMINATED' HAD NOT SUNK INTO OUR CONSCIOUSNESS. OUR SUBSEQUENT DISCUSSION OF THIS INCIDENT HAS SERVED AS A GOOD REVIEW OF COMS AT CTAF (TWR) FACILITIES.

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.