Narrative:

Aircraft #1 on dual training flight with pre-solo student. We stopped on taxiway short of hold line to review traffic clearing, radio and crosswind takeoff procedures. After visually clearing downwind, base, and (I thought) final approach areas, I had student make 'departure' radio call on CTAF, 122.7, and taxi onto runway 28 for takeoff. Student pilot stopped momentarily on runway after getting aligned to check aircraft confign. At that time, I noticed aircraft #2 overhead about 100 ft right and 500 ft above the runway, apparently on a go around. Neither I nor the student either saw this aircraft or heard a radio call announcing its position or intentions prior to that time. We observed the second aircraft re-enter the pattern and land after we had departed the runway for our home base. We did not hear any radioed position reports throughout the pattern, landing and exit from runway. A check of our communication radio in use determined that it was properly tuned, turned on, and volume up and it continued to function normally on our return trip to the controled airport that was our original destination. The primary cause of this occurrence appears to be that neither I nor the student really properly cleared final approach prior to taxi onto the runway, although I thought we had. Contributing factors: high wing confign of C172 may have blocked in part final approach, concentration on instruction and conversation at that point, perhaps an unconscious reliance on radio position reporting by other traffic -- as is the norm at this airport, and the delay on the runway. It is also possible aircraft #2 was on same type of 'modified' final. I do not know if it had radio failure or tried to make position reports. Possible aids in prevention, other than more vigilance on my student's part, might be to slightly angle txwys by perhaps 10 degrees so entire final approach area and area on other side would be visible from high wing aircraft. Normally, I have students stop and angle to runway so this is possible, but didn't do so this time. Another thought would be to move 'stop line' to the corner of the taxiway to force this to happen.

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Original NASA ASRS Text

Title: C172 INSTRUCTOR AND STUDENT FAILED TO SEE ANOTHER C172 ON FINAL PRIOR TO TAXIING INTO POS ON RWY AT AN UNCTLED ARPT RESULTING IN THE AIRBORNE C172 MAKING A GAR.

Narrative: ACFT #1 ON DUAL TRAINING FLT WITH PRE-SOLO STUDENT. WE STOPPED ON TXWY SHORT OF HOLD LINE TO REVIEW TFC CLRING, RADIO AND XWIND TKOF PROCS. AFTER VISUALLY CLRING DOWNWIND, BASE, AND (I THOUGHT) FINAL APCH AREAS, I HAD STUDENT MAKE 'DEP' RADIO CALL ON CTAF, 122.7, AND TAXI ONTO RWY 28 FOR TKOF. STUDENT PLT STOPPED MOMENTARILY ON RWY AFTER GETTING ALIGNED TO CHK ACFT CONFIGN. AT THAT TIME, I NOTICED ACFT #2 OVERHEAD ABOUT 100 FT R AND 500 FT ABOVE THE RWY, APPARENTLY ON A GAR. NEITHER I NOR THE STUDENT EITHER SAW THIS ACFT OR HEARD A RADIO CALL ANNOUNCING ITS POS OR INTENTIONS PRIOR TO THAT TIME. WE OBSERVED THE SECOND ACFT RE-ENTER THE PATTERN AND LAND AFTER WE HAD DEPARTED THE RWY FOR OUR HOME BASE. WE DID NOT HEAR ANY RADIOED POS RPTS THROUGHOUT THE PATTERN, LNDG AND EXIT FROM RWY. A CHK OF OUR COM RADIO IN USE DETERMINED THAT IT WAS PROPERLY TUNED, TURNED ON, AND VOLUME UP AND IT CONTINUED TO FUNCTION NORMALLY ON OUR RETURN TRIP TO THE CTLED ARPT THAT WAS OUR ORIGINAL DEST. THE PRIMARY CAUSE OF THIS OCCURRENCE APPEARS TO BE THAT NEITHER I NOR THE STUDENT REALLY PROPERLY CLRED FINAL APCH PRIOR TO TAXI ONTO THE RWY, ALTHOUGH I THOUGHT WE HAD. CONTRIBUTING FACTORS: HIGH WING CONFIGN OF C172 MAY HAVE BLOCKED IN PART FINAL APCH, CONCENTRATION ON INSTRUCTION AND CONVERSATION AT THAT POINT, PERHAPS AN UNCONSCIOUS RELIANCE ON RADIO POS RPTING BY OTHER TFC -- AS IS THE NORM AT THIS ARPT, AND THE DELAY ON THE RWY. IT IS ALSO POSSIBLE ACFT #2 WAS ON SAME TYPE OF 'MODIFIED' FINAL. I DO NOT KNOW IF IT HAD RADIO FAILURE OR TRIED TO MAKE POS RPTS. POSSIBLE AIDS IN PREVENTION, OTHER THAN MORE VIGILANCE ON MY STUDENT'S PART, MIGHT BE TO SLIGHTLY ANGLE TXWYS BY PERHAPS 10 DEGS SO ENTIRE FINAL APCH AREA AND AREA ON OTHER SIDE WOULD BE VISIBLE FROM HIGH WING ACFT. NORMALLY, I HAVE STUDENTS STOP AND ANGLE TO RWY SO THIS IS POSSIBLE, BUT DIDN'T DO SO THIS TIME. ANOTHER THOUGHT WOULD BE TO MOVE 'STOP LINE' TO THE CORNER OF THE TXWY TO FORCE THIS TO HAPPEN.

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.