X and Y cleared to land same runway had conflict in air traffic area. See and avoid concept.

Attributes
ACN	270628
Time
Date	199404
Day	Fri
Local Time Of Day	0601 To 1200
Place
Locale Reference	atc facility : apa
State Reference	CO
Altitude	agl bound lower : 300 agl bound upper : 300
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	tower : apa tower : cak
Operator	general aviation : personal
Make Model Name	Skylane 182/RG Turbo Skylane/RG
Operating Under FAR Part	Part 91
Flight Phase	descent : approach
Flight Plan	VFR
Aircraft 2
Make Model Name	Any Unknown or Unlisted Aircraft Manufacturer
Operating Under FAR Part	Part 91
Person 1
Affiliation	Other
Function	flight crew : single pilot
Qualification	pilot : instrument pilot : private
Experience	flight time last 90 days : 20 flight time total : 2000
ASRS Report	270628
Person 2
Affiliation	Other
Function	flight crew : single pilot
Qualification	pilot : private
Events
Anomaly	conflict : airborne less severe non adherence : published procedure
Independent Detector	other flight crewa
Resolutory Action	controller : issued new clearance flight crew : took evasive action
Consequence	Other
Miss Distance	horizontal : 1200 vertical : 0
Supplementary
Primary Problem	ATC Human Performance
Air Traffic Incident	other

Narrative:

Small aircraft X was cleared to land after crossing south shore of cherry creek reservoir. When I was approximately 1 mi or less from runway 17L at centennial airport (denver, co) I saw aircraft Y on a short base for runway 17L and called the tower to reconfirm X was cleared to land and that I saw another plane on base leg. The tower controller quickly changed me to land on runway 17R. If I had continued to proceed to land on runway 17L and the other airplane continued on its flight path, we most likely would have had a mid-air collision.

Original NASA ASRS Text

Title: X AND Y CLRED TO LAND SAME RWY HAD CONFLICT IN ATA. SEE AND AVOID CONCEPT.

Narrative: SMA X WAS CLRED TO LAND AFTER XING S SHORE OF CHERRY CREEK RESERVOIR. WHEN I WAS APPROXIMATELY 1 MI OR LESS FROM RWY 17L AT CENTENNIAL ARPT (DENVER, CO) I SAW ACFT Y ON A SHORT BASE FOR RWY 17L AND CALLED THE TWR TO RECONFIRM X WAS CLRED TO LAND AND THAT I SAW ANOTHER PLANE ON BASE LEG. THE TWR CTLR QUICKLY CHANGED ME TO LAND ON RWY 17R. IF I HAD CONTINUED TO PROCEED TO LAND ON RWY 17L AND THE OTHER AIRPLANE CONTINUED ON ITS FLT PATH, WE MOST LIKELY WOULD HAVE HAD A MID-AIR COLLISION.

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.