Narrative:

A helicopter was 2 miles south of the airport and asked to come in and land at their designated helipad. He was instructed to proceed direct to the helipad. Several minutes later a seminole called ready for take-off and I then cleared him departure. The helicopter then asked if I wanted him to hold short of 11R. I stated; yes hold short of 11R and thank-you. If the hold short instruction was not given; the helicopter would have crossed the runway as the seminole began his take off roll. I believe several factors led to this; the first being I believed that that the helicopter had already arrived at his helipad. [Second]; I had only some the shades up and [in] the quadrant the helicopter was arriving from; the shades were down. Due to haze and cloud cover this made the helicopter difficult to spot. When I scanned the runway before I cleared the seminole for take off I believe I would have spotted the helicopter and not even issued the take off clearance. This happened because I failed to locate the helicopter and due to the very light traffic did not feel the need to raise the other the other shades. I got complacent and I hate to admit it lazy. If the traffic would have been moderate or heavy those shades definitely would have been up. [I need to] pay better attention; especially when the traffic is light because that's when the most problems seen to happen. Do not let light traffic influence the way I like the shades; radar or anything else for that matter. I feel like I succumbed to a real rookie mistake and I will teach our newly certified cpc's the trap that I fell into; and more importantly; how to avoid situations like this.

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Original NASA ASRS Text

Title: Tower Controller described a developing conflict between an aircraft cleared for take off and a helicopter arrival who spotted the conflict and delayed his runway crossing; the reporter acknowledging a lack of vigilance.

Narrative: A helicopter was 2 miles south of the airport and asked to come in and land at their designated helipad. He was instructed to proceed direct to the helipad. Several minutes later a Seminole called ready for take-off and I then cleared him departure. The helicopter then asked if I wanted him to hold short of 11R. I stated; yes hold short of 11R and thank-you. If the hold short instruction was not given; the helicopter would have crossed the runway as the Seminole began his take off roll. I believe several factors led to this; the first being I believed that that the helicopter had already arrived at his helipad. [Second]; I had only some the shades up and [in] the quadrant the helicopter was arriving from; the shades were down. Due to haze and cloud cover this made the helicopter difficult to spot. When I scanned the runway before I cleared the Seminole for take off I believe I would have spotted the helicopter and not even issued the take off clearance. This happened because I failed to locate the helicopter and due to the very light traffic did not feel the need to raise the other the other shades. I got complacent and I hate to admit it lazy. If the traffic would have been moderate or heavy those shades definitely would have been up. [I need to] pay better attention; especially when the traffic is light because that's when the most problems seen to happen. Do not let light traffic influence the way I like the shades; RADAR or anything else for that matter. I feel like I succumbed to a real rookie mistake and I will teach our newly certified CPC's the trap that I fell into; and more importantly; how to avoid situations like this.

Data retrieved from NASA's ASRS site as of April 2012 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.