Preliminary report on weather balloon impact on United Airlines windshield

The NTSB has released a preliminary report on the United Airlines Boeing 737 MAX 8 (UA1093) that was hit by a weather balloon mid-flight on Oct. 16. The aircraft was at an altitude of 36,002 ft when an object struck the aircraft's windshield, resulting in the pilot sustaining multiple minor injuries on his right arm. Despite the damage to the windshield, cabin pressurization remained stable and the flight was diverted to the Salt Lake City International Airport (SLC).No other injuries were reported and all passengers were rebooked on a replacement Boeing 737 MAX 9. A post-landing inspection revealed that not only had the inner layer of the windshield shattered, but there was visible damage to the aircraft's nose. Data was later requested for the position of weather balloons, any other aircraft and for any known reentry objects that were large enough to survive the collision. WindBorne Systems Inc. reported that it lost contact with one of its global sounding balloons (GSBs) in the area. GSBs are lightweight, long-duration, high-altitude weather balloons. It had been launched from Washington, traveled down through Oregon and Nevada before turning northeast, and was crossing through Utah at the time of the accident. RELATED STORIES: Object that cracks windshield of United 737 MAX could be weather balloon Crashed UPS MD-11 prelim shows cracks, fractures in engine support Preliminary report released on Hawker maintenance test crash in Michigan GSBs consist of a balloon envelope filled with lift gas, an avionics package and a ballast system for altitude control. Windborne stated that the balloons were designed to minimize harm in the event of impact, as it is made with a thin plastic film. The GSB last reported an altitude of 35,936 ft before it stopped communicating with the ground on the same day of the collision.Windborne stated that it will continue to limit the balloon's time at altitudes between 30,000 and 40,000 ft.