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

A United Airlines plane appears to have collided with a weather balloon while cruising 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 reviewing the situation Sunday, shortly after the National Transportation Safety Board asked. in question He was investigating. Windborne concluded that the Boeing 737 Max likely hit one of its balloons, despite the company doing its best to prevent such collisions.

The plane, flying from Denver to Los Angeles, landed safely in Salt Lake City last Thursday without losing cabin pressure. United said there were 134 passengers and six crew members on board.

Windborne CEO John Dean said he was surprised by the extent of damage to the plane’s windshield because Windborne’s balloons weighed only 2.4 pounds at takeoff, with a simple sandbag serving as ballast. Due to the impact, glass fragments flew in the cockpit.

The company said it complies with all Federal Aviation Administration rules on the size and design of its balloons, which collect data to help improve weather forecasts.

Dean said in a post on

The airline referred questions to the NTSB, which has not responded during the current government shutdown. The NTSB statement did not mention any injuries.

Dean said in an email Tuesday that data on the flight’s location closely matched the last known position and altitude of one of the company’s balloons before it stopped transmitting at the reported time of the collision. Windborne has submitted all of its data to the NTSB, and this will ultimately determine what happens.

Windborne has launched more than 4,000 balloons, and the company said it coordinated with the FAA each time, notifying pilots and sharing live updates on balloon positions with the FAA.

The company said it has already fine-tuned its software to minimize the time balloons spend between 30,000 feet and 40,000 feet. It is also looking at different ballast designs to reduce the force of future crashes and minimize the potential for damage or injury.

NTSB investigators will issue a preliminary report within a few weeks, but the full report may not arrive for more than a year.