Narrative:

I was conducting training during a session on local control/ground control. My trainee was working aircraft X in the local traffic pattern on runway 36. He also had aircraft Z in the traffic pattern on runway 36 and aircraft Y was inbound on a visual approach to runway 9. Aircraft X was in the right downwind and told to extend downwind; the purpose of this was for aircraft X to do his option after aircraft Y had landed and exited the runway. The military flies the uavs and is restricted to only flying in the class delta. The trainee had timed it appropriately so he would turn aircraft X's base prior to the edge of the delta and the conflict would be resolved. The pilot of aircraft X said they needed to turn their base early (about 2 miles from the airport). The trainee reluctantly told aircraft X to turn their base. The supervisor in the tower cab immediately spoke up that the uavs shouldn't be extended in that area as they 'could lose their engine over populated areas' and would rather do 360's in the downwind or enter high key over the airport. Aircraft X was short final runway 36 and was a conflict with aircraft Y landing runway 9. The trainee initiated a go around to aircraft X. This created an unsafe situation as we didn't know these unmanned planes had these special restrictions. This situation wasn't busy or complex; but it created a situation where if aircraft Y needed to go around for any reason; he would have been in conflict with aircraft X; who was also going around; they would have met airborne over the intersection of runway 36 and 9. To make it worse; aircraft Z was in the right downwind across the departure path of runway 9.I have only worked the local unmanned aircraft flown by our military while training and only a few times; but I have noticed the extra care that needs to be taken while working these aircraft. These are VFR aircraft in the traffic pattern; but they are unable to see and avoid. They cannot follow traffic and their traffic patterns need to be completely controlled by the controllers; their bases need to be called to follow traffic and for wake turbulence delays. Not only is this extra work to be constantly watching and timing their patterns; we also need to be mindful if the aircraft goes lost link; where it will fly the shortest route to its lost link orbit location. This could mean the aircraft will immediately make a turn across the airport; if we don't see it happen soon enough and take action to move everyone else; we could have an unmanned aircraft cutting off and flying into arrivals or departures from any one of our three runways. Now management is telling us also that we also need to keep them away from populated areas and that they worry about their engines quitting. I'm not sure why these aircraft are more susceptible to lose an engine than any other single engine aircraft; but if they are and the operators want to remain clear of populated areas; that needs to be addressed in the LOA that they have with tower. The military unit has been vocal about wanting to fly both of their uavs in the pattern at the same time. There are times without them when it is busy and we don't have much room in our local traffic pattern. Sometimes aircraft need to extend and sometimes they need to exit the delta. This is something we expect all aircraft in our pattern to be able to accept and we shouldn't have to make exceptions that jeopardize the safety of others; whether it be the flying public or people on the ground.

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Original NASA ASRS Text

Title: FAR Local Controller reported an operation involving a military UAV that was being conducted not in accordance with the LOA.

Narrative: I was conducting training during a session on LC/GC. My trainee was working Aircraft X in the local traffic pattern on runway 36. He also had Aircraft Z in the traffic pattern on runway 36 and Aircraft Y was inbound on a visual approach to runway 9. Aircraft X was in the right downwind and told to extend downwind; the purpose of this was for Aircraft X to do his option after Aircraft Y had landed and exited the runway. The military flies the UAVs and is restricted to only flying in the Class Delta. The trainee had timed it appropriately so he would turn Aircraft X's base prior to the edge of the Delta and the conflict would be resolved. The pilot of Aircraft X said they needed to turn their base early (about 2 miles from the airport). The trainee reluctantly told Aircraft X to turn their base. The supervisor in the tower cab immediately spoke up that the UAVs shouldn't be extended in that area as they 'could lose their engine over populated areas' and would rather do 360's in the downwind or enter high key over the airport. Aircraft X was short final runway 36 and was a conflict with Aircraft Y landing runway 9. The trainee initiated a go around to Aircraft X. This created an unsafe situation as we didn't know these unmanned planes had these special restrictions. This situation wasn't busy or complex; but it created a situation where if Aircraft Y needed to go around for any reason; he would have been in conflict with Aircraft X; who was also going around; they would have met airborne over the intersection of runway 36 and 9. To make it worse; Aircraft Z was in the right downwind across the departure path of runway 9.I have only worked the local unmanned aircraft flown by our military while training and only a few times; but I have noticed the extra care that needs to be taken while working these aircraft. These are VFR aircraft in the traffic pattern; but they are unable to see and avoid. They cannot follow traffic and their traffic patterns need to be completely controlled by the controllers; their bases need to be called to follow traffic and for wake turbulence delays. Not only is this extra work to be constantly watching and timing their patterns; we also need to be mindful if the aircraft goes lost link; where it will fly the shortest route to its lost link orbit location. This could mean the aircraft will immediately make a turn across the airport; if we don't see it happen soon enough and take action to move everyone else; we could have an unmanned aircraft cutting off and flying into arrivals or departures from any one of our three runways. Now management is telling us also that we also need to keep them away from populated areas and that they worry about their engines quitting. I'm not sure why these aircraft are more susceptible to lose an engine than any other single engine aircraft; but if they are and the operators want to remain clear of populated areas; that needs to be addressed in the LOA that they have with tower. The military unit has been vocal about wanting to fly both of their UAVs in the pattern at the same time. There are times without them when it is busy and we don't have much room in our local traffic pattern. Sometimes aircraft need to extend and sometimes they need to exit the delta. This is something we expect all aircraft in our pattern to be able to accept and we shouldn't have to make exceptions that jeopardize the safety of others; whether it be the flying public or people on the ground.

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.