Narrative:

While working the local control position, I cleared small aircraft X to land runway 36R. Small aircraft Y almost immediately requested takeoff runway 36R. Since small aircraft X was on downwind, I cleared small aircraft Y for takeoff runway 36R expecting no conflict. A small transport touched down runway 36L. Ground control stated 'Z is taxiing to runway 36L, negative TCA squawk.' I confirmed Z position and asked the small transport where he was parking. Due to airfield construction, it was more efficient to issue the small transport a 180 degree (to reduce taxi and coordination time) and I verified he was taxiing without delay visually. Ground control asked if I would issue the TCA squawk on my frequency. I replied 'affirmative,' and looked down at my scratch pad as ground control issued the TCA squawk and I copied it down. As I started to look up, I heard small aircraft X 'power up' into a go around. Searching for the reason, I scanned the runway and saw small aircraft Y in his departure roll phase approximately 200 ft past landing threshold doing approximately 20 KTS. As these observations registered in my mind, small aircraft X overtook small aircraft Y at 70-80 KTS, flying directly over small aircraft Y. Since the situation developed unexpectedly and since small aircraft X overtook small aircraft Y at such a rapid pace, it was obvious an accident would not occur. Small aircraft X was a student pilot on his first solo. I saw no safety-related reason to alter his flight path once he passed small aircraft Y. Small aircraft Y was a student pilot and I felt instructing him to abort his takeoff had the potential to cause more problems than to correct them and had no safety bearance once small aircraft X had passed him. Since small aircraft X did not state 'going around' and I did not instruct small aircraft X to 'go around,' I feel that small aircraft X technically made a low approach, resulting in less than applicable separation as per FAA handbook 7110.65. An area supervisor was working ground control, and I feel that the light traffic contributed to a complacent attitude on my part and, since I expected no conflict, I allowed my attention to be distracted from the developing situation by the twin small transport and the ground controller's statements and request. Once small aircraft X passed small aircraft Y, separation did nothing but increase and no accident resulted. I apologized to the pilots for my inaction and they stated (more or less) 'no problem, don't worry about it.'

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Original NASA ASRS Text

Title: SMA X HAD LTSS NMAC WITH SMA Y. SYS ERROR.

Narrative: WHILE WORKING THE LCL CTL POS, I CLRED SMA X TO LAND RWY 36R. SMA Y ALMOST IMMEDIATELY REQUESTED TKOF RWY 36R. SINCE SMA X WAS ON DOWNWIND, I CLRED SMA Y FOR TKOF RWY 36R EXPECTING NO CONFLICT. A SMT TOUCHED DOWN RWY 36L. GND CTL STATED 'Z IS TAXIING TO RWY 36L, NEGATIVE TCA SQUAWK.' I CONFIRMED Z POS AND ASKED THE SMT WHERE HE WAS PARKING. DUE TO AIRFIELD CONSTRUCTION, IT WAS MORE EFFICIENT TO ISSUE THE SMT A 180 DEG (TO REDUCE TAXI AND COORD TIME) AND I VERIFIED HE WAS TAXIING WITHOUT DELAY VISUALLY. GND CTL ASKED IF I WOULD ISSUE THE TCA SQUAWK ON MY FREQ. I REPLIED 'AFFIRMATIVE,' AND LOOKED DOWN AT MY SCRATCH PAD AS GND CTL ISSUED THE TCA SQUAWK AND I COPIED IT DOWN. AS I STARTED TO LOOK UP, I HEARD SMA X 'PWR UP' INTO A GAR. SEARCHING FOR THE REASON, I SCANNED THE RWY AND SAW SMA Y IN HIS DEP ROLL PHASE APPROX 200 FT PAST LNDG THRESHOLD DOING APPROX 20 KTS. AS THESE OBSERVATIONS REGISTERED IN MY MIND, SMA X OVERTOOK SMA Y AT 70-80 KTS, FLYING DIRECTLY OVER SMA Y. SINCE THE SITUATION DEVELOPED UNEXPECTEDLY AND SINCE SMA X OVERTOOK SMA Y AT SUCH A RAPID PACE, IT WAS OBVIOUS AN ACCIDENT WOULD NOT OCCUR. SMA X WAS A STUDENT PLT ON HIS FIRST SOLO. I SAW NO SAFETY-RELATED REASON TO ALTER HIS FLT PATH ONCE HE PASSED SMA Y. SMA Y WAS A STUDENT PLT AND I FELT INSTRUCTING HIM TO ABORT HIS TKOF HAD THE POTENTIAL TO CAUSE MORE PROBLEMS THAN TO CORRECT THEM AND HAD NO SAFETY BEARANCE ONCE SMA X HAD PASSED HIM. SINCE SMA X DID NOT STATE 'GOING AROUND' AND I DID NOT INSTRUCT SMA X TO 'GAR,' I FEEL THAT SMA X TECHNICALLY MADE A LOW APCH, RESULTING IN LESS THAN APPLICABLE SEPARATION AS PER FAA HANDBOOK 7110.65. AN AREA SUPVR WAS WORKING GND CTL, AND I FEEL THAT THE LIGHT TFC CONTRIBUTED TO A COMPLACENT ATTITUDE ON MY PART AND, SINCE I EXPECTED NO CONFLICT, I ALLOWED MY ATTN TO BE DISTRACTED FROM THE DEVELOPING SITUATION BY THE TWIN SMT AND THE GND CTLR'S STATEMENTS AND REQUEST. ONCE SMA X PASSED SMA Y, SEPARATION DID NOTHING BUT INCREASE AND NO ACCIDENT RESULTED. I APOLOGIZED TO THE PLTS FOR MY INACTION AND THEY STATED (MORE OR LESS) 'NO PROBLEM, DON'T WORRY ABOUT IT.'

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.