Boeing 737 MAX 8

United Airlines

On October 16, 2025, at 0643 mountain daylight time (MDT), United Airlines (UAL) flight 1093, a Boeing 737-8, N17327, was involved in a midair collision with an object while in cruise flight near Moab, Utah. Although the captain sustained minor injuries, none of the other 111 occupants onboard the airplane were injured. The scheduled domestic passenger flight was operating under the provisions of Title 14 Code of Federal Regulations (CFR) Part 121 from Denver International Airport (DEN), Denver, Colorado to Los Angeles International Airport (LAX), Los Angeles, California. Following the incident, the flight diverted to Salt Lake City International Airport (SLC), Salt Lake City, Utah. According to the captain, while established in cruise flight at flight level 360 (36,000 ft pressure altitude), he noticed an object distant on the horizon. Before he could mention the object to the first officer (FO), there was a significant impact to the FO’s forward windshield along with a loud bang. The impact resulted in both pilots being showered with pieces of glass. The captain sustained multiple superficial lacerations to his right arm; the FO was uninjured. Following the event, the flight crew coordinated with air traffic control and initiated a descent. The cabin pressurization remained stable, with no fluctuations throughout the flight. The captain transferred control of the airplane to the FO while he conducted associated checklists and communicated with dispatch and the flight attendants (FAs). During this time, the FO’s window overheat light illuminated and the crew addressed it per the applicable checklist. After coordination with dispatch, the crew selected SLC as the most suitable diversion airport. The captain notified the passengers of the diversion and FAs were briefed to prepare the cabin for landing. The captain then initiated self-care to clean, sterilize, and bandage his wounds on his arm. The captain subsequently resumed pilot flying duties for descent and landing. The flight was vectored for an ILS approach to runway 16L at SLC. The approach and landing were uneventful. The aircraft taxied to the gate under its own power, escorted by airport rescue and firefighting vehicles. Upon arrival at the gate, emergency medical personnel provided the captain with first aid. There were no other reported injuries. After the event was reported, data was requested for the position of weather balloons, any other aircraft, and for any known reentry objects that were large enough to have signification portions survive that might have been in the area of the collision. WindBorne Systems Inc. reported that they lost contact with one of their global sounding balloons (GSBs) that was in the vicinity of the airplane at the time of the accident. The GSB was launched from Spokane, Washington at 1129 MDT on October 15, 2025. The balloon traveled south from Washington, down through Oregon and Nevada before turning northeast, and was crossing though Utah at the time of the accident. There was a Notice to Airman, GEG 10/068, issued at 816 MDT for the balloon launch operations at Spokane that expired at 1700 MDT the same day, October 15, 2025. The GSB stopped communicating with the ground on October 16, 2025, between 0636:16 and 0643:36 MDT. The last communication from the GSB reported that the pressure altitude was 35,936 ft (which had been oscillating between 35,800 and 36,200 ft over the preceding hour). The GSB self-reported location was latitude 38.53142N and longitude 109.41600W and the wind was 73 knots from the southwest. According to WindBorne, the GSB is a lightweight, long duration high-altitude weather balloon platform operated under the provisions of Title 14 CFR Part 101.1. It is an unmanned free balloon. The GSB system consists of a balloon envelope filled with lift gas, an avionics package for flight control, communications, and sensing, and a ballast system for altitude control. According to Windborne the GSBs are designed with the intent to minimize harm in the event of an impact during flight or landing. No large metal or high-stiffness structural elements are employed. The balloon envelope and the ballast container are a thin, low tensile strength, plastic film. The silica ballast is relatively low density and low grain-size. The windshield installed in N17327 was manufactured by PPG Aerospace and was designed to withstand the flight and pressurization loads encountered during flight while providing visibility for the pilots. From outboard to inboard, the windshield consists of a thermally tempered glass pane, a conductive heating film for deice capabilities, a urethane interlayer, a vinyl interlayer, a urethane interlayer, and a thermally tempered glass pane. The windshield is surrounded by a stainless-steel z-bar encased in a moisture seal to attach it to the fuselage. A coating is applied to the outer surface of the outboard pane to improve the ability to shed water in rainy conditions. Windshields are certified to withstand the impact of a four-pound bird without penetration, to be capable of withstanding the maximum cabin pressurization loads with the failure of a single pane, and the internal pane must be non-splintering. The inboard pane of glass is considered a structural pane, the vinyl interlayer is considered a structural fail-safe pane, and the outboard pane of glass is considered a non-structural pane for this design. The damaged right windshield from the accident airplane, P/N 29-5612-9-9008, S/N 23089H0823, was manufactured on March 30, 2023. The damaged windshield was removed from the airplane and sent to the NTSB Materials Lab in Washington, DC for examination. In addition, the flight data and the cockpit voice recorder were sent to the NTSB Vehicle Recorder Laboratory in Washington, DC. A preliminary review of the data from the cockpit voice and flight data recorders revealed that at the time of the collision, the airplane’s track was to the southwest at 233° magnetic (nearly the reciprocal of the balloon track), at a pressure altitude of 36,002 ft, and a groundspeed of 395 knots. This investigation is ongoing.

Ethiopian Airlines

On March 10, 2019, at 05:38 UTC, Ethiopian Airlines flight 302, Boeing 737-8(MAX), ET-AVJ, took off from Addis Ababa Bole Int. Airport bound to Nairobi, Kenya Jomo Kenyatta Int. Airport. Shortly after takeoff, the Angle of Attack sensor recorded value became erroneous and the left stick shaker activated and remained active until near the end of the flight. In addition, the airspeed and altitude values from the left air data system began deviating from the corresponding right side values. Due to flight control problems, the Captain was unable to maintain the flight path and requested to return back to the departure airport. The crew lost control of the aircraft which crashed at 5: 44 UTC 28 NM South East of Addis Ababa near Ejere village. Both CVR and DFDR were recovered in the morning of March 11. The Boeing 737 MAX was grounded until the end of 2020. A preliminary report is available below.

Lion Air

The aircraft departed runway 25L at Jakarta-Soekarno-Hatta Airport at 0621LT bound for Pangkal Pinang, carrying 181 passengers and 8 crew members. The crew was cleared to climb but apparently encountered technical problems and was unable to reach a higher altitude than 5,375 feet. At this time, the flight shows erratic speed and altitude values. The pilot declared an emergency and elected to return to Jakarta when control was lost while at an altitude of 3,650 feet and at a speed of 345 knots. The airplane entered a dive and crashed 12 minutes after takeoff into the Kerawang Sea, about 63 km northeast from its departure point. The airplane disintegrated on impact and few debris were already recovered but unfortunately no survivors. It has been reported that the aircraft suffered various technical issues during the previous flight on Sunday night but was released for service on Monday morning. Brand new, the airplane was delivered to Lion Air last August 18. At the time of the accident, weather conditions were considered as good. The Cockpit Voice Recorder (CVR) was found on 14 January 2019. In the initial stages of the investigation, it was found that there is a potential for repeated automatic nose down trim commands of the horizontal stabilizer when the flight control system on a Boeing 737 MAX aircraft receives an erroneously high single AOA sensor input. Such a specific condition could among others potentially result in the stick shaker activating on the affected side and IAS, ALT and/or AOA DISAGREE alerts. The logic behind the automatic nose down trim lies in the aircraft's MCAS (Maneuvering Characteristics Augmentation System) that was introduced by Boeing on the MAX series aircraft. This feature was added to prevent the aircraft from entering a stall under specific conditions. On November 6, 2018, Boeing issued an Operations Manual Bulletin (OMB) directing operators to existing flight crew procedures to address circumstances where there is erroneous input from an AOA sensor. On November 7, the FAA issued an emergency Airworthiness Directive requiring "revising certificate limitations and operating procedures of the airplane flight manual (AFM) to provide the flight crew with runaway horizontal stabilizer trim procedures to follow under certain conditions.