A C172 experienced a near midair collision with another cessna in the pattern at apa.

Attributes
ACN	767232
Time
Date	200712
Local Time Of Day	1201 To 1800
Place
Locale Reference	airport : apa.airport
State Reference	CO
Altitude	msl single value : 6100
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	tower : apa.tower tower : zzz.tower
Operator	general aviation : instructional
Make Model Name	Skyhawk 172/Cutlass 172
Operating Under FAR Part	Part 91
Flight Phase	descent : approach
Route In Use	approach : traffic pattern
Aircraft 2
Controlling Facilities	tower : apa.tower
Operator	general aviation : personal
Make Model Name	Cessna Aircraft Undifferentiated or Other Model
Flight Phase	descent : approach
Person 1
Function	other personnel other
Qualification	pilot : multi engine pilot : atp pilot : cfi
Experience	flight time last 90 days : 100 flight time total : 14000 flight time type : 300
ASRS Report	767232
Events
Anomaly	conflict : nmac other spatial deviation
Independent Detector	other flight crewa
Resolutory Action	none taken : detected after the fact
Consequence	faa : reviewed incident with flight crew
Supplementary
Problem Areas	Flight Crew Human Performance
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	Pilot Deviation

Narrative:

While administering a commercial asel examination at centennial airport (apa) the following took place. 2 parallel runways were in use; (runways 17L and 17R). They were being controled by 2 separate controllers on 2 separate frequencys. We were established in a r-hand pattern using runway 17R. The applicant was assigned the task for a short-field landing. We were on an approximately 3/4 mi final approach and cleared to land runway 17R; following a husky. At that point a high wing cessna descended from our right rear quadrant over the top down to a front (left) quadrant toward runway 17L for a landing. During the descent the cessna that was landing runway 17L missed us by 50-100 ft. After talking to the controllers it was established that the cessna that near missed us had been cleared to land from a left base leg and had overshot the base into the pattern for runway 17R.

Original NASA ASRS Text

Title: A C172 EXPERIENCED A NMAC WITH ANOTHER CESSNA IN THE PATTERN AT APA.

Narrative: WHILE ADMINISTERING A COMMERCIAL ASEL EXAM AT CENTENNIAL ARPT (APA) THE FOLLOWING TOOK PLACE. 2 PARALLEL RWYS WERE IN USE; (RWYS 17L AND 17R). THEY WERE BEING CTLED BY 2 SEPARATE CTLRS ON 2 SEPARATE FREQS. WE WERE ESTABLISHED IN A R-HAND PATTERN USING RWY 17R. THE APPLICANT WAS ASSIGNED THE TASK FOR A SHORT-FIELD LNDG. WE WERE ON AN APPROX 3/4 MI FINAL APCH AND CLRED TO LAND RWY 17R; FOLLOWING A HUSKY. AT THAT POINT A HIGH WING CESSNA DSNDED FROM OUR R REAR QUADRANT OVER THE TOP DOWN TO A FRONT (L) QUADRANT TOWARD RWY 17L FOR A LNDG. DURING THE DSCNT THE CESSNA THAT WAS LNDG RWY 17L MISSED US BY 50-100 FT. AFTER TALKING TO THE CTLRS IT WAS ESTABLISHED THAT THE CESSNA THAT NEAR MISSED US HAD BEEN CLRED TO LAND FROM A L BASE LEG AND HAD OVERSHOT THE BASE INTO THE PATTERN FOR RWY 17R.

Data retrieved from NASA's ASRS site as of January 2009 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.