Narrative:

[I was] working lake hood (lhd); a VFR tower. Aircraft typically call up the tower before they are even at the runway holding short and say they are at the runway ready for takeoff. We have runway 13/31; and at the end of the runway; a hangar that blocks the view of the 13 approach end. You can not see any aircraft holding short of runway 13. Merrill tower (mri) is only about 3 or 4 flying miles away from us and there frequency is very close to ours on ground as well as local. Ground at anchorage (anc) is 121.9 and mri is 121.7; local at lhd is 126.8 mri is 126.0. Pilots at mri switch them up constantly. An aircraft called me with what I understood to be 'tower aircraft X holding short ready to go northbound and request far 93 deviation.' I scanned the radar and runway and said 'aircraft X lake hood tower runway 31 cleared for take off and northbound far part 93 deviation approved.' upon listening to the tapes he apparently did say he was at runway 25 ready to go. Then after I cleared him he said departing runway 25. I changed another aircraft that was on my frequency to the departure controller. Then I had a question in my mind and went back to the aircraft X and asked if he was at lhd or mri and he said at 25 and I looked over to anchorage because anc has 7/25 runways and then I told him lhd does not have runway 25 and by that time he was up on radar from mri and I told him to contact mri tower immediately. I then contacted mri on the loop line (a shout line to the tower) and told them an aircraft was on my frequency departing off of their airport. They said they had it. I then immediately told my supervisor about the incident. Recommendation I should have questioned his position and ensured it. Instead it was slow and I thought normal operations. I would make the tower frequencies further apart on numbers. Also to always be vigilant in slow traffic periods at a VFR tower or any position.

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Original NASA ASRS Text

Title: LHD controller cleared a departure for takeoff only to discover the aircraft was actually at MRI; a nearby airport; the reporter listing similar frequency issues and failed vigilance as causal factors.

Narrative: [I was] working Lake Hood (LHD); a VFR Tower. Aircraft typically call up the Tower before they are even at the runway holding short and say they are at the runway ready for takeoff. We have Runway 13/31; and at the end of the runway; a hangar that blocks the view of the 13 approach end. You can not see any aircraft holding short of Runway 13. Merrill Tower (MRI) is only about 3 or 4 flying miles away from us and there frequency is very close to ours on ground as well as local. Ground at Anchorage (ANC) is 121.9 and MRI is 121.7; Local at LHD is 126.8 MRI is 126.0. Pilots at MRI switch them up constantly. An aircraft called me with what I understood to be 'Tower Aircraft X holding short ready to go northbound and request FAR 93 deviation.' I scanned the RADAR and runway and said 'Aircraft X Lake Hood Tower Runway 31 cleared for take off and northbound FAR part 93 deviation approved.' Upon listening to the tapes he apparently did say he was at Runway 25 ready to go. Then after I cleared him he said departing Runway 25. I changed another aircraft that was on my frequency to the Departure Controller. Then I had a question in my mind and went back to the Aircraft X and asked if he was at LHD or MRI and he said at 25 and I looked over to Anchorage because ANC has 7/25 Runways and then I told him LHD does not have Runway 25 and by that time he was up on RADAR from MRI and I told him to contact MRI Tower immediately. I then contacted MRI on the loop line (a shout line to the Tower) and told them an aircraft was on my frequency departing off of their airport. They said they had it. I then immediately told my Supervisor about the incident. Recommendation I should have questioned his position and ensured it. Instead it was slow and I thought normal operations. I would make the tower frequencies further apart on numbers. Also to always be vigilant in slow traffic periods at a VFR Tower or any position.

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.