Toa controller described a potential conflict after clearing a helicopter for takeoff at the antenna...

Narrative:

Helicopter called up for departure from the antenna site; a position adjacent to taxiway alpha; our main taxiway that local control occasionally uses to depart helicopters. I was working the local position. I coordinated for a departure on taxiway alpha from the helicopter's position and the ground controller in training approved it. I scanned the taxiway and did not see anything that would be an obstruction for the helicopter; saw none; and cleared the helicopter for take off on taxiway alpha then continued to work other aircraft in the airspace. The controller in charge pointed out that there was a aircraft on alpha that the helicopter was about to overfly. I instructed the helicopter to remain north of the aircraft and he said he would comply. Helicopter passed off the the aircraft's right and departed without further incident. Recommendation; moving the antennas off the antenna site to a different location since they partially obstruct the view of alpha. The only reason I can think of for not noticing the aircraft on the taxiway is that the antennas camouflaged him at the same time I was scanning the area. Incidences like this do not happen often; so the effort of moving the antenna site would probably not be worth the benefit of having a completely unobstructed view of taxiway alpha.

Original NASA ASRS Text

Title: TOA Controller described a potential conflict after clearing a helicopter for takeoff at the antenna farm without observing an aircraft on Taxiway Alpha; the reporter notes restricted visibility near the antenna area.

Narrative: Helicopter called up for departure from the antenna site; a position adjacent to Taxiway Alpha; our main taxiway that Local Control occasionally uses to depart helicopters. I was working the Local position. I coordinated for a departure on Taxiway Alpha from the helicopter's position and the Ground Controller in training approved it. I scanned the taxiway and did not see anything that would be an obstruction for the helicopter; saw none; and cleared the helicopter for take off on Taxiway Alpha then continued to work other aircraft in the airspace. The CIC pointed out that there was a aircraft on Alpha that the helicopter was about to overfly. I instructed the helicopter to remain north of the aircraft and he said he would comply. Helicopter passed off the the aircraft's right and departed without further incident. Recommendation; moving the antennas off the antenna site to a different location since they partially obstruct the view of Alpha. The only reason I can think of for not noticing the aircraft on the taxiway is that the antennas camouflaged him at the same time I was scanning the area. Incidences like this do not happen often; so the effort of moving the antenna site would probably not be worth the benefit of having a completely unobstructed view of Taxiway Alpha.

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.

Attributes
ACN	975795
Time
Date	201110
Local Time Of Day	1801-2400
Place
Locale Reference	TOA.Tower
State Reference	CA
Aircraft 1
Make Model Name	Robinson Helicopter Undifferentiated or Other Model
Flight Phase	Initial Climb
Route In Use	None
Flight Plan	VFR
Aircraft 2
Make Model Name	Small Aircraft
Flight Phase	Taxi
Route In Use	None
Person 1
Function	Local
Qualification	Air Traffic Control Fully Certified
Events
Anomaly	ATC Issue All Types Conflict Ground Conflict Less Severe Deviation - Procedural Published Material / Policy

Toa controller described a potential conflict after clearing a helicopter for takeoff at the antenna farm without observing an aircraft on taxiway alpha; the reporter notes restricted visibility near the antenna area.