Narrative:

While waiting for departure on runway 26 at dxr I observed small aircraft X on long final. An small transport in front of me departed and I became #1 holding short. I again looked at the final approach path to see small aircraft X on about a 1/8 mi final at around 100 ft AGL and watched as another small aircraft Y turned left base to final immediately over the first aircraft. At that point it would have been impossible for either aircraft to see the other. I could not distinguish the airplanes and was afraid that any transmission to them would have caused the lower aircraft to climb into the upper plane. I transmitted, 'tower you have 2 aircraft on short final.' after a pause, the tower followed with instructions for 'small aircraft Y, go around.' the upper aircraft then climbed and moved to the right side of the runway for the go around. I do not know how the tower knew which aircraft was on top, or if it was a lucky guess. Much has been written about caution in the traffic pattern at uncontrolled airports -- it must be emphasized to pilots that such vigilance needs to be utilized at controled airports also. Certainly the airplane going from base to final did not see the aircraft on final. I did not notice the previous tower communications so I cannot comment on it. However, it would appear that their sequencing of landing aircraft had a problem somewhere.

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Original NASA ASRS Text

Title: SMA X HAD POSSIBLE NMAC WITH SMA Y ON FINAL APCH TO LNDG. SEE AND AVOID CONCEPT.

Narrative: WHILE WAITING FOR DEP ON RWY 26 AT DXR I OBSERVED SMA X ON LONG FINAL. AN SMT IN FRONT OF ME DEPARTED AND I BECAME #1 HOLDING SHORT. I AGAIN LOOKED AT THE FINAL APCH PATH TO SEE SMA X ON ABOUT A 1/8 MI FINAL AT AROUND 100 FT AGL AND WATCHED AS ANOTHER SMA Y TURNED L BASE TO FINAL IMMEDIATELY OVER THE FIRST ACFT. AT THAT POINT IT WOULD HAVE BEEN IMPOSSIBLE FOR EITHER ACFT TO SEE THE OTHER. I COULD NOT DISTINGUISH THE AIRPLANES AND WAS AFRAID THAT ANY XMISSION TO THEM WOULD HAVE CAUSED THE LOWER ACFT TO CLB INTO THE UPPER PLANE. I TRANSMITTED, 'TWR YOU HAVE 2 ACFT ON SHORT FINAL.' AFTER A PAUSE, THE TWR FOLLOWED WITH INSTRUCTIONS FOR 'SMA Y, GAR.' THE UPPER ACFT THEN CLBED AND MOVED TO THE R SIDE OF THE RWY FOR THE GAR. I DO NOT KNOW HOW THE TWR KNEW WHICH ACFT WAS ON TOP, OR IF IT WAS A LUCKY GUESS. MUCH HAS BEEN WRITTEN ABOUT CAUTION IN THE TFC PATTERN AT UNCTLED ARPTS -- IT MUST BE EMPHASIZED TO PLTS THAT SUCH VIGILANCE NEEDS TO BE UTILIZED AT CTLED ARPTS ALSO. CERTAINLY THE AIRPLANE GOING FROM BASE TO FINAL DID NOT SEE THE ACFT ON FINAL. I DID NOT NOTICE THE PREVIOUS TWR COMS SO I CANNOT COMMENT ON IT. HOWEVER, IT WOULD APPEAR THAT THEIR SEQUENCING OF LNDG ACFT HAD A PROBLEM SOMEWHERE.

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.