The National Transportation Safety Board (NTSB) has confirmed that a United Airlines Boeing 737 colliding with a weather balloon caused significant damage during a flight over Utah last month. The incident occurred on October 16, 2025, when United Flight 1093 was cruising at 36,000 feet en route from Denver to Los Angeles. The impact resulted in glass shards entering the cockpit, leading to injuries for the captain, who sustained lacerations to his right arm.
During the flight, the captain observed an object on the horizon but was unable to alert the first officer before the aircraft struck it, producing a loud bang. Initially, there was speculation that space debris was to blame, but the NTSB’s investigation revealed the object was a high-altitude weather balloon.
Details of the Incident
According to the NTSB report, the weather balloon, identified as a global sounding balloon (GSB), had been launched by California-based WindBorne Systems from Spokane, Washington, on October 15. The balloon traveled south, crossing through states including Oregon and Nevada, before entering Utah’s airspace just before the collision. The NTSB noted, “The GSB was in the vicinity of the United jet’s flight path when the impact occurred.”
NTSB Chair Jennifer Homendy stated that the midair collision could have led to devastating consequences for the aircraft and its occupants. While the captain was the only one injured, damage sustained by the aircraft could have resulted in a more serious situation. Fortunately, cabin pressurization remained stable, and the first officer’s window overheat light activated briefly but did not lead to further complications.
Response and Aftermath
In response to the incident, WindBorne Systems emphasized that its GSBs are designed to minimize damage during collisions. The company utilizes lightweight materials, such as thin plastic films and silica, to reduce the risk of severe impact damage. Measures are being implemented to improve air traffic alerts and minimize time spent in commercial airspace, alongside plans to further decrease the weight of their GSBs.
The aircraft involved in the incident, a two-year-old Boeing 737 MAX 8 with the registration number N17327, has remained grounded for over a month. After safely diverting to Salt Lake City following the collision, the aircraft made a brief flight to Chicago Rockford on October 19 but has not flown since. The damaged windshield was removed for examination at the NTSB Materials Lab in Washington, D.C.
Aircraft windshields, including those on the United 737 MAX, are engineered to withstand impacts from various objects, such as birds. The NTSB highlights that they are certified to endure impacts from a four-pound bird without penetration, featuring non-splintering internal panes. The windshield on the involved aircraft, manufactured by PPG Aerospace, comprises multiple layers designed for durability and safety.
As investigations continue, the aviation community watches closely for any additional findings that may lead to improved safety protocols in response to this unusual incident.
