A United Airlines emergency landing probably caused by a collision with a weather balloon

A United Airlines plane appears to have collided with a weather balloon while flying at 36,000 feet over Utah last week, shattering layers of its windshield and forcing an emergency landing. A California company called Windborne Systems said it began looking into the situation Sunday, not long after the National Transportation Safety Board said it was investigating. Windborne quickly concluded that the Boeing 737 Max had most likely run into one of its balloons, despite the company’s best efforts to prevent such collisions. The plane, which was flying from Denver to Los Angeles, did not lose cabin pressure and landed safely in Salt Lake City last Thursday. United said 134 passengers and six crew members were on board. Windborne CEO John Dean said he was surprised by the extent of the damage to the plane’s windshield because Windborne’s balloons weigh only 2.4 pounds at takeoff with a simple bag of sand acting as ballast. The impact sent glass fragments flying into the cabin. The company said it follows all Federal Aviation Administration rules for the size and design of its balloons that collect data to help improve weather forecasts. “I find this extremely concerning, and unacceptable in the event of a collision, regardless of what the official regulations are, that resulted in injury to a pilot, which I am simply not okay with at all,” Dean said in a post on X. The airline referred questions to the NTSB, which is not responding during the current state shutdown. The NTSB statement did not mention any injuries. Dean said in an email Tuesday that data about the location of the flight now matches the last known location and altitude of one of the company’s balloons before it stopped broadcasting right around the reported time of the collision. Windborne sent all of its data to the NTSB, which will ultimately determine what happened. Windborne has launched more than 4,000 balloons, and the company said it coordinates with the FAA each time, filing notifications for pilots and sharing live updates on balloon positions with the FAA. The company said it has already adjusted the software for its balloons to reduce the time they spend between 30,000 feet and 40,000 feet. It also looks at different ballast designs to reduce the force of any future collisions and reduce the potential for damage or injury. NTSB investigators will release a preliminary report in a few weeks, but the full report may not come for more than a year.