Narrative:

This was a routine training flight with a student pilot. The student was practicing flight at minimum ctlable airspeed. The aircraft was in a landing confign, 30 degree flaps, indicating approximately 50 mph. We had been flying in this confign for several minutes on a northeast heading. While in the process of reestablishing level cruise flight we saw the low wing aircraft pass almost directly overhead with minimal vertical sep, probably less than 50', although the suddenness of the occurrence made the distance difficult to judge. We remained level at 2700' MSL and observed the other aircraft diverging from us on an angle to the left. I estimate that there was about a 30 degree difference between our headings. We had had no visibility contact with the other aircraft prior to seeing it appear from the area blocked by our right wing and pass to the left. There was no opportunity for us to take any evasive action. It seems unlikely that the other aircraft had us in sight since it did not appear that he had been taking evasive action. I do not believe that our flight attitude contributed to this incident. We had been maintaining an altitude of 2700' MSL immediately prior to, during and after it occurred. It is possible that, if the other plane did have us in sight, our acceleration could have caused him to misjudge our closure rate. I believe the low wing's flight path was from behind and to the right, so that even had my attention not been divided between guiding the student and scanning for traffic I still would not have seen it. I believe the major contributing factor was that each aircraft's wings obscured the view of the other. Only if one or both of us saw the other at a greater distance could this have been avoided.

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Original NASA ASRS Text

Title: CLOSE PROX GA SMA LOW WING PASSED 50' OVER GA SMA HIGH WING.

Narrative: THIS WAS A ROUTINE TRAINING FLT WITH A STUDENT PLT. THE STUDENT WAS PRACTICING FLT AT MINIMUM CTLABLE AIRSPD. THE ACFT WAS IN A LNDG CONFIGN, 30 DEG FLAPS, INDICATING APPROX 50 MPH. WE HAD BEEN FLYING IN THIS CONFIGN FOR SEVERAL MINUTES ON A NE HDG. WHILE IN THE PROCESS OF REESTABLISHING LEVEL CRUISE FLT WE SAW THE LOW WING ACFT PASS ALMOST DIRECTLY OVERHEAD WITH MINIMAL VERTICAL SEP, PROBABLY LESS THAN 50', ALTHOUGH THE SUDDENNESS OF THE OCCURRENCE MADE THE DISTANCE DIFFICULT TO JUDGE. WE REMAINED LEVEL AT 2700' MSL AND OBSERVED THE OTHER ACFT DIVERGING FROM US ON AN ANGLE TO THE L. I ESTIMATE THAT THERE WAS ABOUT A 30 DEG DIFFERENCE BTWN OUR HDGS. WE HAD HAD NO VIS CONTACT WITH THE OTHER ACFT PRIOR TO SEEING IT APPEAR FROM THE AREA BLOCKED BY OUR R WING AND PASS TO THE L. THERE WAS NO OPPORTUNITY FOR US TO TAKE ANY EVASIVE ACTION. IT SEEMS UNLIKELY THAT THE OTHER ACFT HAD US IN SIGHT SINCE IT DID NOT APPEAR THAT HE HAD BEEN TAKING EVASIVE ACTION. I DO NOT BELIEVE THAT OUR FLT ATTITUDE CONTRIBUTED TO THIS INCIDENT. WE HAD BEEN MAINTAINING AN ALT OF 2700' MSL IMMEDIATELY PRIOR TO, DURING AND AFTER IT OCCURRED. IT IS POSSIBLE THAT, IF THE OTHER PLANE DID HAVE US IN SIGHT, OUR ACCELERATION COULD HAVE CAUSED HIM TO MISJUDGE OUR CLOSURE RATE. I BELIEVE THE LOW WING'S FLT PATH WAS FROM BEHIND AND TO THE R, SO THAT EVEN HAD MY ATTN NOT BEEN DIVIDED BTWN GUIDING THE STUDENT AND SCANNING FOR TFC I STILL WOULD NOT HAVE SEEN IT. I BELIEVE THE MAJOR CONTRIBUTING FACTOR WAS THAT EACH ACFT'S WINGS OBSCURED THE VIEW OF THE OTHER. ONLY IF ONE OR BOTH OF US SAW THE OTHER AT A GREATER DISTANCE COULD THIS HAVE BEEN AVOIDED.

Data retrieved from NASA's ASRS site as of August 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.