CH7A pilot and a C172 had an near midair collision in apa class D.

Attributes
ACN	617355
Time
Date	200404
Day	Sun
Local Time Of Day	1201 To 1800
Place
Locale Reference	airport : apa.airport
State Reference	CO
Altitude	agl single value : 250
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	tower : apa.tower
Operator	general aviation : personal
Make Model Name	Champion Citabria
Operating Under FAR Part	Part 91
Flight Phase	descent : intermediate altitude descent : approach landing : go around
Route In Use	approach : traffic pattern
Flight Plan	None
Aircraft 2
Controlling Facilities	tower : apa.tower
Operator	general aviation : personal
Make Model Name	Skyhawk 172/Cutlass 172
Operating Under FAR Part	Part 91
Flight Phase	descent : approach
Route In Use	approach : traffic pattern
Person 1
Affiliation	other
Function	flight crew : single pilot
Qualification	pilot : commercial pilot : cfi
Experience	flight time last 90 days : 30 flight time total : 1820 flight time type : 800
ASRS Report	617355
Person 2
Function	flight crew : single pilot
Events
Anomaly	conflict : nmac non adherence : required legal separation non adherence : clearance non adherence : far non adherence : published procedure
Independent Detector	other flight crewa
Resolutory Action	flight crew : executed go around flight crew : took evasive action other
Consequence	faa : reviewed incident with flight crew
Miss Distance	horizontal : 0 vertical : 150
Supplementary
Problem Areas	Flight Crew Human Performance ATC Human Performance
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	Pilot Deviation other

Narrative:

Our aircraft was cleared for full stop landing at apa on runway 17L. Aircraft behind us on left base for runway 17L reported us in sight. On short final, I observed a C172 fly under us on short final. I radioed over that there was an aircraft under us and I was going around. The tower controller asked us if we wanted runway 28 for landing. I replied 'roger that.' there was no indication from the other plane that he saw us on short final. Upon calling the tower and talking to the controller, he admitted that he had been complacent as we were the only 2 aircraft in the pattern.

Original NASA ASRS Text

Title: CH7A PLT AND A C172 HAD AN NMAC IN APA CLASS D.

Narrative: OUR ACFT WAS CLRED FOR FULL STOP LNDG AT APA ON RWY 17L. ACFT BEHIND US ON L BASE FOR RWY 17L RPTED US IN SIGHT. ON SHORT FINAL, I OBSERVED A C172 FLY UNDER US ON SHORT FINAL. I RADIOED OVER THAT THERE WAS AN ACFT UNDER US AND I WAS GOING AROUND. THE TWR CTLR ASKED US IF WE WANTED RWY 28 FOR LNDG. I REPLIED 'ROGER THAT.' THERE WAS NO INDICATION FROM THE OTHER PLANE THAT HE SAW US ON SHORT FINAL. UPON CALLING THE TWR AND TALKING TO THE CTLR, HE ADMITTED THAT HE HAD BEEN COMPLACENT AS WE WERE THE ONLY 2 ACFT IN THE PATTERN.

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.