Narrative:

I was working local control west (lcw); and aircraft X called ready to go off runway 1L. I cleared aircraft X for takeoff at XA36; heading 300; which he read back. Approximately 2 miles north of the airport at XA38; aircraft X tagged up on the radar; I told him to contact departure and asked him to pass on flight conditions if able. He read back that he would like to return to runway 1L. I issued him left closed traffic; cleared him to land on runway 1L; and asked if he needed assistance; he said he did not and did not state the reason for return. At this time the ground controller was coordinating with approach; letting them know that aircraft X was coming back to land. It appeared that aircraft X had started a wide left turn into the downwind. About 4 miles northwest of the airport; at XA39; aircraft X contacted me saying he had changed his mind and was requesting a frequency change. I was unsure of his intentions; since I was expecting him to join the downwind; and verified if he wanted to come back to land; to which he said no. At that point he was nearing the boundary of the class D airspace; I switched him to departure for the second time; and he read it back. At this time the ground controller coordinated with approach that aircraft X was no longer returning to [the airport]; and that he's coming to them on a 300 heading. Approach acknowledged. Approximately 12 seconds later; at XA40; about 5 miles northwest of [the airport]; a low altitude alert went off for aircraft X. Not sure if aircraft X was still on my frequency; I issued the low altitude alert to him just in case. He was still on my frequency at that time; and read back that he will check his altitude. A short while later; aircraft X flew in close proximity to obstructions northwest of [the airport]; the obstructions are 2300 MSL and aircraft X was at 2600 MSL. Coordination with approach for a different heading when it is first noticed that the heading will take an aircraft directly toward the obstruction. If unable to coordinate a different heading; instruct the aircraft to climb without delay and keep him on my frequency; advise approach.

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Original NASA ASRS Text

Title: Two Tower Controllers reported a P180 failed to change frequencies; which resulted in maintaining an altitude which triggered a low altitude alert.

Narrative: I was working Local Control West (LCW); and Aircraft X called ready to go off Runway 1L. I cleared Aircraft X for takeoff at XA36; heading 300; which he read back. Approximately 2 miles north of the airport at XA38; Aircraft X tagged up on the radar; I told him to contact Departure and asked him to pass on flight conditions if able. He read back that he would like to return to Runway 1L. I issued him left closed traffic; cleared him to land on Runway 1L; and asked if he needed assistance; he said he did not and did not state the reason for return. At this time the Ground controller was coordinating with Approach; letting them know that Aircraft X was coming back to land. It appeared that Aircraft X had started a wide left turn into the downwind. About 4 miles northwest of the airport; at XA39; Aircraft X contacted me saying he had changed his mind and was requesting a frequency change. I was unsure of his intentions; since I was expecting him to join the downwind; and verified if he wanted to come back to land; to which he said no. At that point he was nearing the boundary of the Class D airspace; I switched him to departure for the second time; and he read it back. At this time the Ground controller coordinated with approach that Aircraft X was no longer returning to [the airport]; and that he's coming to them on a 300 heading. Approach acknowledged. Approximately 12 seconds later; at XA40; about 5 miles northwest of [the airport]; a Low Altitude alert went off for Aircraft X. Not sure if Aircraft X was still on my frequency; I issued the Low Altitude alert to him just in case. He was still on my frequency at that time; and read back that he will check his altitude. A short while later; Aircraft X flew in close proximity to obstructions northwest of [the airport]; The obstructions are 2300 MSL and Aircraft X was at 2600 MSL. Coordination with approach for a different heading when it is first noticed that the heading will take an aircraft directly toward the obstruction. If unable to coordinate a different heading; instruct the aircraft to climb without delay and keep him on my frequency; advise approach.

Data retrieved from NASA's ASRS site 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.