The CEO of Windborne, a company that launches weather balloons, has posted on social media that he believes it was one of his company’s devices that collided with a United Airlines Boeing 737 MAX last Thursday. “Yes I think this was a WindBorne balloon,” John Dean, who also helped found the company, said on Facebook. “We learned about UA1093 and the potential that it was related to one of our balloons at 11pm PT on Sunday and immediately looked into it. At 6am PT, we sent our preliminary investigation to both NTSB and FAA, and we are working with both of them to investigate further.” As we reported Sunday, the focus of the NTSB’s investigation is now on the weather balloon theory.
The incident lit up the internet last week as it was first reported that the aircraft might have hit space junk, shattering one layer of the FO’s windscreen and causing scratches and abrasions to one of the pilot’s arms. No one else was hurt and the aircraft, which was on its way to Los Angeles from Denver, diverted safely to Salt Lake City. Windborne launches long-duration balloons that stay aloft for weeks and travel thousands of miles, providing real-time atmospheric data for weather forecasting. The instrument package uses sand as ballast, which is consistent with the abrasions on the windscreen frame on the 737.
Update – November 20, 2025: The NTSB has issued a preliminary investigation report: https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/201877/pdf
“My airliner was hit by a bag of sand during cruise at 36K’.”
That’ll sound good on an insurance report 🫤
That said, it’s likely good that it wasn’t anything harder?
Drones below 400’AGL and sand above FL350.
What is today’s airspace coming to ?
That’ll be the title of Ralph Nader’s next book … “Unsafe at any altitude” 😁
Astounding that this is first time. Is it?
Assuming balloons of this type have transponders – is that a valid assumption? – will ATC now establish no-fly zones under balloons from surface to the balloons’ altitude? With allowance for windage affecting falling sandbags?
If they don’t have transponders, they should.
The outcome could have been much worse. I can only wonder what would have happened if the balloon envelope took out both engines, or jammed flight controls.
For all my ATC career at a terminal facility, if a weather station was near by, we would receive the occasional phone call advising of a balloon release in 5 minutes. To this day, I’ve never been sure what we were supposed to do about it, except say thank you. The balloons went up really fast, and during the years never had an issue with one. Maybe a more controlling LOA between balloon folks and facility is in effect now.
Considering the maneuvering capabilities of the two craft, it’s likelier the MAX hit the balloon.
The pilots must have both been heads down. I’ve seen balloons from tens of miles away and I can’t imagine what it must take to not see and actually hit one. Solid IMC maybe but you don’t see that very often at FL360 this time of year.