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Balloon halts traffic at SFO
San Francisco International Airport halts traffic and orders multiple go-arounds due to a suspected drone/balloon.
Summary
A Horizon Air pilot reported a black, square object—initially thought to be a drone—flying just 200 feet above their aircraft during takeoff at SFO. Air Traffic Control immediately halted departures and ordered four arriving flights to perform go-arounds while they and ground crews tracked the object, which was eventually identified as a balloon.
Analysis
The incident began when Horizon 2035 reported a "black and square-like" object, approximately one foot in size, hovering over Runway 1 Right just after they rotated for takeoff. Given the severe safety risks drones pose to jet engines and airframes, the SFO tower controller took immediate action, halting all departures and putting arriving aircraft on alert. This triggered a period of high-intensity coordination as the controller managed multiple aircraft on short final approach.
As the object drifted across the airfield, descriptions from various pilots fluctuated between a drone, birds, and a balloon. This uncertainty is common in aviation, where high speeds and small objects make visual identification difficult. To maintain safety, the tower ordered go-arounds for Moxy 600, American 1580, JetBlue 1515, and United 648. A go-around is a standard safety procedure where an aircraft aborts its landing and climbs back to a safe altitude to try again later.
The technical management of the situation involved "Ops" vehicles (airport operations) driving onto the taxiways to visually track the object from the ground. The controller skillfully balanced the safety of arrivals while coordinating ground movements to get eyes on the hazard. The object was eventually tracked moving toward the "Ones" (Runways 01L and 01R) and then out toward Highway 101 and the San Francisco Bay.
Once SkyWest 4691 confirmed the object was "right above" them and clearly a balloon, and other pilots reported it was clear of the approach paths, the tower began resuming normal operations. This incident highlights the significant disruption a simple Mylar balloon can cause at a major international hub, leading to thousands of dollars in extra fuel costs and delays for the affected airlines.
Original ATC Communication
Plain English Translation
HORIZON 2035
SFO Tower, Horizon 2035.
HORIZON 2035
San Francisco Tower, this is Horizon flight 2035.
TOWER
Horizon 2035?
TOWER
Horizon 2035, go ahead?
HORIZON 2035
Yeah, I think there was a drone above the runway—just like 50 feet above us.
HORIZON 2035
Yeah, I think we just saw a drone above the runway—it was only about 50 feet above our plane.
TOWER
Okay, give me as much information as you can because that’s a big deal. So, was it over One Right?
TOWER
Okay, tell me everything you can because that’s a serious safety issue. Was it over the right-hand runway?
HORIZON 2035
Yeah, One Right, just after we rotated. It appeared there was a drone, probably 200 feet above us.
HORIZON 2035
Yes, the right runway, just as we lifted our nose for takeoff. It looked like a drone, maybe 200 feet above us.
TOWER
Okay. Did you rotate prior to the 28s?
TOWER
Okay. Did you lift off before you reached the crossing runways?
HORIZON 2035
We rotated right at the 28s.
HORIZON 2035
We lifted off right where the runways intersect.
TOWER
Right at the 28s. Okay. And do you have a color or any description of it?
TOWER
Right at the intersection. Got it. Do you have a color or any way to describe what it looked like?
HORIZON 2035
It was black and square-like, maybe about a foot.
HORIZON 2035
It was black and shaped like a square, maybe about a foot wide.
TOWER
Okay, square and about a foot. Okay, I think we have it. Thanks for letting us know, Horizon 2035. And there was no damage? It didn't hit you, did it?
TOWER
Okay, a one-foot square. I think we’ve spotted it. Thanks for the report, Horizon 2035. Any damage to your plane? It didn't actually strike you, did it?
HORIZON 2035
No, we were slightly under it.
HORIZON 2035
No, we passed just underneath it.
TOWER
United 380, contact NorCal Departure. Good day. All aircraft, we’re going to stop all departures at San Francisco for now until we get this taken care of. And to any of the planes out there, do you guys have a view of this thing?
TOWER
United 380, switch over to the departure controllers now. Have a good flight. Attention all aircraft, we’re grounding all takeoffs at San Francisco for now until we handle this. To the other planes on the ground, does anyone else see this thing?
SKYWEST 4670
SkyWest 4670 on One Right. We don't see anything, but thanks for stopping the traffic.
SKYWEST 4670
This is SkyWest 4670 waiting on the right runway. We don't see it from here, but thanks for keeping us on the ground for safety.
TOWER
Yeah, we actually see it from the tower. It’s off the—what were you guys saying? One Right, maybe near Foxtrot? Or at Ten Left, like One Right maybe at Charlie?
TOWER
Yeah, we can actually see it from the control tower. It’s near—where were you guys? The right runway near taxiway Foxtrot? Or maybe where the runways meet at taxiway Charlie?
SKYWEST 4691
Tower, SkyWest 4691. We see two birds circling near the tower.
SKYWEST 4691
Tower, this is SkyWest 4691. We can see two birds circling near the tower building.
TOWER
Okay. Moxy 600, on visual 28 Left.
TOWER
Alright, Moxy 600, we see you've got the left runway in sight for your approach.
MOXY 600
Moxy 600, continue. Possible go-around, slow to approach speed.
MOXY 600
Moxy 600, we're continuing in. We're prepared to abort the landing if needed, slowing down to our final approach speed now.
TOWER
They’re saying maybe it’s a black balloon. We’re getting it off the tower. But yeah, if you guys could keep looking. American 1580, bridge visual 28 Right.
TOWER
We're hearing reports it might just be a black balloon. We're watching for it from the tower cab. But yeah, if you guys could keep an eye out. American 1580, use the bridge as a landmark and line up for the right runway.
AMERICAN 1580
American 1580, slow to approach speed now. Expect a possible go-around.
AMERICAN 1580
American 1580, slowing down to landing speed now. We're ready to pull up and try again if we have to.
TOWER
Korean Air, do you see anything? Do you see a drone anywhere?
TOWER
Korean Air, do you see anything out there? Do you spot a drone anywhere?
KOREAN AIR 214
Standby, Korean Air 214.
KOREAN AIR 214
Give us a second to look, Korean Air 214.
SKYWEST 4670
And SkyWest 4670 sees something, possibly over the 28s. I can’t quite make it out from here, though.
SKYWEST 4670
And SkyWest 4670 sees something, it looks like it's right over the main runways. I can’t quite tell what it is from here, though.
TOWER
Because we’re thinking maybe it’s a balloon. It’s over Foxtrot now. To any aircraft on the frequency, do you see it?
TOWER
We’re starting to think it’s just a balloon. It’s over taxiway Foxtrot now. To any pilots on this frequency, do you see it?
PILOT
Go ahead.
PILOT
Go ahead, I'm listening.
TOWER
Yeah, okay. So it sounds like it’s near maybe Foxtrot and Lima. It’s square and black. It should be right there, like right where you are. You may have passed it off your right.
TOWER
Yeah, okay. It sounds like it’s near the intersection of taxiways Foxtrot and Lima. It’s square and black. It should be right there where you are—you might have just passed it on your right side.
PILOT
Tower, November 7 Victor Tango, 1,900.
PILOT
Tower, this is plane 7 Victor Tango, we're at 1,900 feet.
TOWER
It should be heading to your left. Do you see it? Does it look like a balloon or a drone? Moxy 600, confirm cleared to land.
TOWER
It should be drifting toward your left. Do you see it? Does it look like a balloon or a drone? Moxy 600, just confirming you are still cleared to land.
TOWER
Moxy 600, go around. Fly heading 260.
TOWER
Moxy 600, abort your landing. Climb out and fly a compass heading of 260.
MOXY 600
Going around, Moxy 600.
MOXY 600
Aborting the landing and climbing out, Moxy 600.
TOWER
American 1580, fly runway heading, go around.
TOWER
American 1580, abort your landing, fly straight ahead following the runway path and climb.
AMERICAN 1580
Fly runway heading, go around, American 1580.
AMERICAN 1580
American 1580, we’re aborting the landing and flying straight ahead.
TOWER
Moxy 600, turn left heading 260. It looks like it’s by Golf now, heading to your left. American 1580, you have the aircraft ahead and to your left in sight?
TOWER
Moxy 600, turn left to heading 260. It looks like the object is near taxiway Golf now, moving to your left. American 1580, do you see that other aircraft ahead and to your left?
AMERICAN 1580
We do have them in sight, American 1580.
AMERICAN 1580
We have them in sight, American 1580.
TOWER
American 1580, on runway heading, maintain 3,000. Contact NorCal 135.1.
TOWER
American 1580, keep flying straight, stay at 3,000 feet. Switch over to Northern California regional control on frequency 135.1.
AMERICAN 1580
Runway heading, 3,000, 35.1, American 1580.
AMERICAN 1580
Flying straight, 3,000 feet, switching to 135.1, American 1580.
TOWER
Moxy 600, fly heading 260, maintain 3,100. Contact NorCal 135.1.
TOWER
Moxy 600, fly heading 260 and stay at 3,100 feet. Switch over to Northern California regional control on 135.1.
MOXY 600
3,100, Moxy 600, 35.1.
MOXY 600
3,100 feet, Moxy 600, switching to 135.1.
TOWER
November 7 Victor Tango, make a right 360 at your current position. We can see it in the tower. Hold on one second, I’m going to have someone that’s got it in sight stay on frequency. It sounds like it’s at Golf and Lima. And it’s moving towards the Ones now.
November 7 Victor Tango, you know, it’s going to be a bit. I can’t get you into the airspace right now. Leave San Francisco Class Bravo airspace and contact NorCal 135.1.
TOWER
November 7 Victor Tango, fly a full circle to the right where you are. We can see the object from the tower. Wait just a second, I’m keeping a pilot who sees it on the radio. It sounds like it’s by taxiways Golf and Lima, and it’s moving toward the Runway One area now.
November 7 Victor Tango, look, it’s going to be a while. I can’t let you into this busy airport area right now. Exit the San Francisco restricted airspace and contact regional control on 135.1.
PILOT
135.1, and we’ll leave the Bravo.
PILOT
Switching to 135.1, and we’ll exit the restricted airspace.
JETBLUE 1515
JetBlue 1515, visual 28 Left.
JETBLUE 1515
JetBlue 1515, we have Runway 28 Left in sight.
TOWER
Okay, Ops 40 and company, cross Runway 28 Right, cross Runway 28 Left at Echo. United 194 Heavy, at Foxtrot, cross Runway One Left, cross Runway One Right.
TOWER
Okay, Airport Operations 40 and team, cross Runway 28 Right and 28 Left at taxiway Echo. United 194, you large heavy jet, cross Runway One Left and One Right at taxiway Foxtrot.
UNITED 194 HEAVY
At Foxtrot, cross One Left, cross One Right, United 194 Heavy.
UNITED 194 HEAVY
Crossing Runway One Left and One Right at taxiway Foxtrot, United 194.
TOWER
Ops 40 and company, you can proceed on Bravo. Just use caution for that United, and you can go down to Golf. Now it’s headed down by Mike. So you can cross Runway One Left, cross Runway One Right, and whatever you need to do. Just let me know.
United 648, plan on a possible go-around. Continue, slow it back. JetBlue 1515, plan on a possible go-around.
TOWER
Operations 40 and team, you can move onto taxiway Bravo. Just watch out for that United plane, and you can head down to taxiway Golf. The object is moving toward taxiway Mike now. You’re clear to cross Runway One Left and One Right—do whatever you need to do to track it, just keep me posted.
United 648, be ready to abort your landing. Keep coming, but slow down. JetBlue 1515, be ready to abort your landing as well.
JETBLUE 1515
Roger, 1515.
JETBLUE 1515
Understood, 1515.
TOWER
Is it Ops 24 and company or Ops 30 and company? Okay, it sounds like it’s above buildings over Lima and Mike now. Ops 30 and company, cross Runway One Left. You can proceed on Runway One Right and head over to Lima and Mike.
United 648, plan on a possible go-around. I’m going to wait just one more second to see if these guys can see if it’s a balloon or a drone. JetBlue 1515, just continue one more second. I’m just going to see if they’re able to see it. It sounds like it’s over the ridge line at Lima and Mike, by the water now.
TOWER
Is that Operations team 24 or 30? Okay, it sounds like it’s above the buildings near taxiways Lima and Mike now. Team 30, cross Runway One Left. You can go onto Runway One Right and head toward those taxiways.
United 648, be prepared to abort your landing. I’m going to wait just a moment to see if the ground crew can tell if it’s a balloon or a drone. JetBlue 1515, keep your approach going for another second. I want to see if they can spot it. It sounds like it’s over the ridge near the water by taxiways Lima and Mike now.
VIRGIN 190 HEAVY
Tower, Virgin 190 Heavy, lining up 28 Left.
VIRGIN 190 HEAVY
Tower, this is the large Virgin flight 190, we are pulling onto the left-side runway 28 now.
TOWER
JetBlue 1515, go around. Turn left heading 260, maintain 3,100. United 648, go around. Fly runway heading.
TOWER
JetBlue 1515, abort your landing. Turn left toward the west and stay at 3,100 feet. United 648, you also abort your landing. Fly straight out, following the line of the runway.
UNITED 648
Runway heading, 648.
UNITED 648
Flying straight out over the runway, United 648.
TOWER
JetBlue 1515, turn left heading 260. Virgin 190 Heavy, slow your approach speed. Expect a possible go-around.
TOWER
JetBlue 1515, turn left now toward heading 260. Virgin 190, slow down as you come in. Be ready, you might have to abort this landing too.
VIRGIN 190 HEAVY
Roger, Virgin 190 Heavy.
VIRGIN 190 HEAVY
Understood, Virgin 190.
TOWER
JetBlue 1515, on heading 260, maintain 3,100. United 648, maintain 3,000.
United 648, do you have that JetBlue in sight?
TOWER
JetBlue 1515, stay on that westward turn and keep your altitude at 3,100 feet. United 648, stay at 3,000 feet. United 648, can you see that JetBlue plane near you?
UNITED 648
We have them in sight, United 648.
UNITED 648
We can see them from here, United 648.
TOWER
United 648, maintain visual separation from that JetBlue Airbus. Ops 40 and company, cross Runway One Right, proceed on Lima. JetBlue 1515, contact NorCal 135.1. United 648, NorCal 135.1.
Virgin 190 Heavy, it looks like it’s over the water now. We have a drone that is to the south of the field over the water. Do you feel comfortable landing?
TOWER
United 648, keep your eyes on that JetBlue Airbus and stay clear of it. Airport crews, cross over the right-side runway one and take the Lima taxiway. JetBlue 1515 and United 648, switch over to the regional controllers. Virgin 190, the drone we're watching seems to be over the water south of the airport now. Are you okay to keep coming in for a landing?
VIRGIN 190 HEAVY
We’re happy to continue, Virgin 190 Heavy.
VIRGIN 190 HEAVY
We're fine to keep our approach going, Virgin 190.
TOWER
Virgin 190 Heavy, Runway 28 Left, cleared to land. Drone reported; currently it sounds like it’s over the water south of the field.
TOWER
Virgin 190, you're authorized to land on the left-side runway 28. Just be aware of that drone; sounds like it's currently over the water to the south.
VIRGIN 190 HEAVY
Roger, we’ll keep an eye out and let you know. Cleared to land 28 Left.
VIRGIN 190 HEAVY
Got it, we'll watch for it and report back. Authorized to land on 28 Left.
TOWER
Yeah, you probably have the best vantage point. It’s off your left, near kind of where Mike and Lima are as you come in.
TOWER
Right, you'll have a better view than us. It should be off to your left, near where the Mike and Lima taxiways are as you're flying in.
SKYWEST 4670
Tower, SkyWest 4670. I saw it going over to my left at around 10 o’clock. It looks to be a balloon. I’d say it’s over top of Ten Left, maybe about three-quarters of the way down the runway to the north.
SKYWEST 4670
Tower, SkyWest 4670. I just saw it pass to my left, slightly ahead of me. It actually looks like a balloon. I’d say it’s hovering over the left-side runway 10, about three-quarters of the way down toward the north end.
TOWER
Okay. Actually, it sounds like from our vantage point, it’s over Highway 101. So, everyone at One Right, do you feel comfortable departing now?
TOWER
Okay. From our view up here, it looks like it's over Highway 101. For everyone waiting at the right-side runway one, do you feel safe taking off now?
SKYWEST 4691
Tower, SkyWest 4691. We’ve got something just off our 12 o’clock, moving towards us, not that far in front of us. Maybe the Hotel area, above us.
SKYWEST 4691
Tower, SkyWest 4691. We see something directly in front of us, moving our way and getting pretty close. It looks like it's above us near the Hotel taxiway area.
TOWER
Okay, Ops vehicles, the SkyWest that just reported that is third in line for One Right. Jessup 561, visual for 28 Right. Virgin 190 Heavy, did you see anything?
TOWER
Alright, ground crews, that SkyWest flight that just reported the object is third in line for runway One Right. Jessup 561, you have the runway in sight for 28 Right. Virgin 190, you're a large jet, did you see anything out there?
VIRGIN 190 HEAVY
Negative, Virgin 190 Heavy.
VIRGIN 190 HEAVY
No, we didn't see anything, Virgin 190.
TOWER
Virgin 190 Heavy, turn left at Echo, contact Ground .8. Use caution for the heavy. Jessup 561, it sounds like we may have a drone that’s observed, or it could be a balloon, but it’s over near the Ones. Do you feel comfortable landing on 28 Right?
TOWER
Virgin 190, turn left onto taxiway Echo and switch to the ground controllers on the .8 frequency. Watch out for the other large jet. Jessup 561, it sounds like we might have a drone spotted, or it could be a balloon, but it’s over near the number one runways. Are you okay with landing on runway 28 Right?
JESSUP 561
Yeah, we’re comfortable landing 28 Right.
JESSUP 561
Yeah, we’re fine with landing on 28 Right.
TOWER
Jessup 561, the Virgin Atlantic that just landed did not observe the drone, and it appears that it’s remaining south of the 28s. Jessup 561, Runway 28 Right, cleared to land.
TOWER
Jessup 561, the Virgin Atlantic flight that just landed didn't see the drone, and it looks like it’s staying south of the 28 runways. Jessup 561, you are cleared to land on runway 28 Right.
JESSUP 561
28 Right, cleared to land, Jessup 561.
JESSUP 561
Cleared to land on 28 Right, Jessup 561.
TOWER
United 58 Heavy, San Francisco Tower, taxiway Foxtrot, cross Runway One Left, cross Runway One Right. SkyWest 3424, visual 28 Left.
TOWER
United 58, large jet, this is San Francisco Tower. Take taxiway Foxtrot and cross both runway One Left and One Right. SkyWest 3424, you have runway 28 Left in sight.
SKYWEST 3424
Visual 28 Left, SkyWest 3424.
SKYWEST 3424
We see runway 28 Left, SkyWest 3424.
TOWER
SkyWest 3424, we had a drone reported—it could be a balloon. It’s now more near One Right. I believe one of the aircraft did have it in sight. The Virgin Atlantic that just landed did not observe it. Do you feel comfortable landing Runway 28 Left?
TOWER
SkyWest 3424, we had a drone reported—it might be a balloon. It’s now more toward runway One Right. I believe one of the other planes did see it. The Virgin Atlantic that just landed didn't see it. Do you feel okay landing on runway 28 Left?
SKYWEST 3424
We’ll go ahead and keep an eye out for it. SkyWest 3424.
SKYWEST 3424
We’ll go ahead and keep a sharp eye out for it. SkyWest 3424.
TOWER
SkyWest 3424, Runway 28 Left, cleared to land. Any of the aircraft holding at One Right, do you see anything else out there?
TOWER
SkyWest 3424, you're cleared to land on runway 28 Left. To any of the planes waiting to depart at runway One Right, do you see anything else out there?
PILOT
It’s off to my right. We see it. We’re comfortable for takeoff.
PILOT
It’s off to my right side. We see it. We’re still comfortable taking off.
TOWER
Okay, no one is cleared for takeoff right now, so everyone just stand by. But you are comfortable to take off, is that what you said? It sounds like the controller that did have it in sight has reported that it is clear of the airport and heading more towards the freeway. So I’m going to ask everyone if they’re comfortable, and then they’re watching it, so we’ll keep an eye on it. It should be behind everyone.
TOWER
Okay, nobody is cleared for takeoff right now, so everyone just wait. But you’re saying you are comfortable taking off? It sounds like the controller who had it in sight reported it's clear of the airport and heading toward the freeway. I’m going to ask everyone if they’re comfortable, and we’ll keep watching it. It should be behind everyone now.
SKYWEST 4691
It’s right above us now. Looks like a balloon.
SKYWEST 4691
It’s right above us now. It looks like a balloon.
TOWER
Right above you, okay. It sounds like a balloon. Okay, thank you.
TOWER
Right above you, okay. It sounds like it's just a balloon. Okay, thank you.
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