Narrative:

While conducting an operation on martha's vineyard; we had a near miss about 1 mile north of the runway 24 centerline. We started in the west end of island making north to south tracks. As we approached the class D airspace we increased our communication with the tower informing them where we were at all times. We were squawking a discreet code. We were cleared several times to cross airport at 900 ft by the tower operator. Traffic was very light. I remember one other aircraft in the area. I heard him over the airport. Not sure of altitude but high. We were on our 2nd or 3rd pass north to south. We encountered traffic while flying north at 900 ft. The conflicting traffic was at our 12 o'clock position and maybe 50 ft above us. His gear was down he was roughly on right base leg for runway 24. I do not believe he saw us; neither the pilot in command nor tower operator made any comment about the near miss. We did not either. 1) we did not hear any warning from tower that we had conflicting traffic approaching us. 2) I heard tower operator indicate to other aircraft that tower radar was giving him trouble. 3) this was second tower operator we worked with. First was a female; second operator was a male voice. We had been talking to the male operator for at least 45 minutes prior to the incident. Contributing factors: 1) I am not sure what was happening in the tower cab; it did not appear tower operator had a working radar otherwise we never would have gotten this close based on past experience. 2) we had three qualified pilots in my aircraft. No one heard the other aircraft on the frequency. 3) I believe the other aircraft was being operated by an air carrier based on the type and color of aircraft. There may have been some complacency on everyone's part.

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Original NASA ASRS Text

Title: A pilot on a government mission near MVY and communicating with MVY Tower had a near miss with a light twin aircraft while the reporter was crossing Runway 24 final and the other aircraft was turning base.

Narrative: While conducting an operation on Martha's Vineyard; we had a near miss about 1 mile north of the Runway 24 centerline. We started in the west end of island making north to south tracks. As we approached the Class D airspace we increased our communication with the Tower informing them where we were at all times. We were squawking a discreet code. We were cleared several times to cross airport at 900 FT by the Tower Operator. Traffic was very light. I remember one other aircraft in the area. I heard him over the airport. Not sure of altitude but high. We were on our 2nd or 3rd pass north to south. We encountered traffic while flying north at 900 FT. The conflicting traffic was at our 12 o'clock position and maybe 50 FT above us. His gear was down he was roughly on right base leg for Runway 24. I do not believe he saw us; neither the pilot in command nor Tower Operator made any comment about the near miss. We did not either. 1) We did not hear any warning from Tower that we had conflicting traffic approaching us. 2) I heard Tower Operator indicate to other aircraft that Tower radar was giving him trouble. 3) This was second Tower Operator we worked with. First was a female; second operator was a male voice. We had been talking to the male operator for at least 45 minutes prior to the incident. Contributing factors: 1) I am not sure what was happening in the Tower Cab; it did not appear Tower Operator had a working radar otherwise we never would have gotten this close based on past experience. 2) We had three qualified pilots in my aircraft. No one heard the other aircraft on the frequency. 3) I believe the other aircraft was being operated by an air carrier based on the type and color of aircraft. There may have been some complacency on everyone's part.

Data retrieved from NASA's ASRS site as of April 2012 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.