Narrative:

I was instructing a developmental on local control. A C172; student pilot on a cross country solo; reported at the highway 91/interstate 15 intersection; located southeast of cno. The developmental instructed the skyhawk to make right traffic for runway 8L. The pilot acknowledged runway 8L. When the skyhawk was within 3 miles of the landing runway; the developmental cleared the skyhawk to land on runway 8L. The pilot acknowledged runway 8L. A bonanza; requested to depart runway 8R the developmental cleared the bonanza to depart runway 8R. The skyhawk was turning right base and appeared to be lining up for runway 8L. A few seconds later a transmission was heard; asking if the cessna was landing on runway 8R. Immediately after that; the C172 transmitted landing runway 8R. When the skyhawk was about to cross the landing threshold; I transmitted 'bonanza; cancel take off clearance; hold short of runway 8R.' the bonanza acknowledged the hold short instructions and never crossed the runway 8R hold short markings. The cessna crossed the threshold at about 300 ft AGL and landed on runway 8R. I instructed the C172 to turn left onto runway 3 and hold short of runway 8L. The pilot acknowledged; hold short of runway 8L. The skyhawk did not turn on runway 3. I then told the C172 to turn off the runway and again to hold short of runway 8L. The pilot turned off runway 8R at lima and did not acknowledge the hold short instructions the second time. I had to give detailed taxi instructions to the C172 and to cross runway 8L at delta. The pilot acknowledged the runway crossing and crossed runway 8L. When the C172 had exited runway 8R; I cleared the bonanza for takeoff on runway 8R. The control tower is located north of runway 8L/8R. During the time of the incident; the sun was located low over the horizon; reducing the visibility for the tower to observe the final legs for both runway 8L/right. A ridge line; located 4 to 6 miles west of the airport; which runs northwest to southeast; adds to the difficulty of observing aircraft landing on both runways. The aircraft 'blend in' with the color of the terrain when their altitudes are below the top of the ridge line; especially when the sun is low over the horizon. Another factor which increases the difficulty of observing the aircraft are the window shades. The tower window shades; even clean; have numerous scratches; adding to the observation difficulties. During the next 20 minutes; pilots on left downwind (north of the runways) were reporting that they were unable to visually observe the aircraft they were instructed to follow due to the location of the sun. After the incident; the tower shades were raised and I put sun glasses on to help see the aircraft on final. I recommend the tower shades be replaced with new ones to improve tower visibility.

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Original NASA ASRS Text

Title: CNO Controller described a near conflict event when traffic on final landed on a parallel runway with traffic about to depart; the Controller noting the sun position and window shade condition as problematic.

Narrative: I was instructing a Developmental on Local Control. A C172; student pilot on a cross country solo; reported at the Highway 91/Interstate 15 intersection; located southeast of CNO. The Developmental instructed the Skyhawk to make right traffic for Runway 8L. The pilot acknowledged Runway 8L. When the Skyhawk was within 3 miles of the landing runway; the Developmental cleared the Skyhawk to land on Runway 8L. The pilot acknowledged Runway 8L. A Bonanza; requested to depart Runway 8R the Developmental cleared the Bonanza to depart Runway 8R. The Skyhawk was turning right base and appeared to be lining up for Runway 8L. A few seconds later a transmission was heard; asking if the Cessna was landing on Runway 8R. Immediately after that; the C172 transmitted landing Runway 8R. When the Skyhawk was about to cross the landing threshold; I transmitted 'Bonanza; cancel take off clearance; hold short of Runway 8R.' The Bonanza acknowledged the hold short instructions and never crossed the Runway 8R hold short markings. The Cessna crossed the threshold at about 300 FT AGL and landed on Runway 8R. I instructed the C172 to turn left onto Runway 3 and hold short of Runway 8L. The pilot acknowledged; hold short of Runway 8L. The Skyhawk did not turn on Runway 3. I then told the C172 to turn off the runway and again to hold short of Runway 8L. The pilot turned off Runway 8R at Lima and did not acknowledge the hold short instructions the second time. I had to give detailed taxi instructions to the C172 and to cross Runway 8L at Delta. The pilot acknowledged the runway crossing and crossed Runway 8L. When the C172 had exited Runway 8R; I cleared the Bonanza for takeoff on Runway 8R. The Control Tower is located north of Runway 8L/8R. During the time of the incident; the sun was located low over the horizon; reducing the visibility for the Tower to observe the final legs for both Runway 8L/R. A ridge line; located 4 to 6 miles west of the airport; which runs northwest to southeast; adds to the difficulty of observing aircraft landing on both runways. The aircraft 'blend in' with the color of the terrain when their altitudes are below the top of the ridge line; especially when the sun is low over the horizon. Another factor which increases the difficulty of observing the aircraft are the window shades. The Tower window shades; even clean; have numerous scratches; adding to the observation difficulties. During the next 20 minutes; pilots on left downwind (north of the runways) were reporting that they were unable to visually observe the aircraft they were instructed to follow due to the location of the sun. After the incident; the Tower shades were raised and I put sun glasses on to help see the aircraft on final. I recommend the Tower shades be replaced with new ones to improve Tower visibility.

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.