Apa controller described a pattern conflict event when traffic cut out another aircraft; the reporte...

Narrative:

I was working local control. There were several aircraft in the VFR traffic pattern. A PA28 was told to enter a midfield left downwind and follow cessna traffic. The PA28 entered the pattern correctly. Moments later I instructed the PA28 to follow cessna traffic. The PA28 responded I have the cessna traffic insight. The PA28 turned final in front of two aircraft on final causing the C172 to abort the approach and fly west for pattern reentry. The PA28 did not follow the cessna traffic that was pointed out to him causing the C172 to abort his approach. In hindsight I believe the PA28 did not have the correct traffic insight that he was instructed to follow. During that time of day (angle of the sun) and runway configuration it is very difficult to see aircraft turning base to final. Adding to an already difficult situation is the pull down sun shades in the tower cab. The shades help with blocking the brightness of the sun but due to the condition; (multiple scratches); of the shades it makes it extremely difficult to see aircraft. With a better sun shade setup I believe it will be easier for the controller to see aircraft out the window and ensure that control instructions are followed.

Original NASA ASRS Text

Title: APA Controller described a pattern conflict event when traffic cut out another aircraft; the reporter indicating the sun glare and shade problems may have contributed to the issuance of incorrect aircraft locations.

Narrative: I was working Local Control. There were several aircraft in the VFR traffic pattern. A PA28 was told to enter a midfield left downwind and follow Cessna traffic. The PA28 entered the pattern correctly. Moments later I instructed the PA28 to follow Cessna traffic. The PA28 responded I have the Cessna traffic insight. The PA28 turned final in front of two aircraft on final causing the C172 to abort the approach and fly west for pattern reentry. The PA28 did not follow the Cessna traffic that was pointed out to him causing the C172 to abort his approach. In hindsight I believe the PA28 did not have the correct traffic insight that he was instructed to follow. During that time of day (angle of the sun) and runway configuration it is very difficult to see aircraft turning base to final. Adding to an already difficult situation is the pull down sun shades in the tower cab. The shades help with blocking the brightness of the sun but due to the condition; (multiple scratches); of the shades it makes it extremely difficult to see aircraft. With a better sun shade setup I believe it will be easier for the Controller to see aircraft out the window and ensure that control instructions are followed.

Data retrieved from NASA's ASRS site as of July 2013 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.

Attributes
ACN	1062389
Time
Date	201301
Local Time Of Day	1801-2400
Place
Locale Reference	APA.Airport
State Reference	CO
Aircraft 1
Make Model Name	PA-28 Cherokee/Archer/Dakota/Pillan/Warrior
Operating Under FAR Part	Part 91
Flight Phase	Landing
Route In Use	None
Flight Plan	VFR
Aircraft 2
Make Model Name	Skyhawk 172/Cutlass 172
Operating Under FAR Part	Part 91
Flight Phase	Landing
Route In Use	None
Flight Plan	VFR
Person 1
Function	Local
Qualification	Air Traffic Control Developmental
Events
Anomaly	ATC Issue All Types Conflict Airborne Conflict Deviation - Procedural Published Material / Policy

Apa controller described a pattern conflict event when traffic cut out another aircraft; the reporter indicating the sun glare and shade problems may have contributed to the issuance of incorrect aircraft locations.