Introduction
On 24 March 2025, a United Airlines Airbus A319-100 aircraft, registration N837UA, operating flight UA-2166 from San Francisco International Airport (SFO), California, to Bozeman Yellowstone International Airport (BZN), Montana, experienced an in-flight engine anomaly that necessitated the shutdown of one of its engines. The flight crew made the decision to divert to Boise Air Terminal (BOI), Idaho, where the aircraft landed safely without further incident. Emergency services met the aircraft upon landing for a precautionary inspection.
The Federal Aviation Administration (FAA) has initiated an investigation into the incident. There were no reported injuries among the occupants, and the aircraft taxied to the apron following a brief runway stop.
Aircraft and Flight Information
The aircraft involved in the occurrence was an Airbus A319-100, powered by two IAE V2522-A5 turbofan engines. At the time of the incident, the aircraft was operating a scheduled domestic passenger service under the call sign UA-2166. The flight was carrying a full complement of passengers and crew, although no specific occupancy numbers have been released.
The aircraft had departed from San Francisco at approximately 12:30 local time and was en route at cruising altitude. While step climbing from FL350 to FL370 during cruise, the crew identified an issue with one of the engines and made the decision to cease the climb and shut the engine down as a precautionary measure.
Sequence of Events
At cruising altitude approximately 30 minutes prior to the planned descent into Bozeman, the flight crew detected abnormal indications related to the No. 2 (right-hand) engine. The engine, identified as an IAE V2522-A5, displayed performance parameters outside normal operating limits.
Following standard operating procedures, the crew initiated a controlled shutdown of the affected engine and declared a precautionary emergency. The decision was made to divert to the nearest suitable airport, Boise Air Terminal (BOI), which offered favourable weather conditions, suitable runway length, and proximity.
The aircraft descended under single-engine operation and was vectored for an approach to runway 28L at BOI. At approximately 14:15 local time, the aircraft conducted a safe landing. Emergency services were pre-positioned at the airport in anticipation of a possible fire or further abnormality, though none was observed. The aircraft remained on the runway for approximately five minutes to allow ground personnel to complete a visual assessment, after which it taxied to the terminal apron under its own power.
Post-Landing Assessment
Preliminary post-landing inspection by airport emergency response units and airline maintenance technicians did not identify visible structural damage or fire. However, the affected engine remains subject to further internal examination. The aircraft was withdrawn from service pending diagnostic testing and engineering evaluation.
Passengers were deplaned in a routine manner and were either rebooked on alternate flights or accommodated as per United Airlines’ contingency protocols. No injuries or medical issues were reported during the flight or disembarkation.
FAA Statement
In a public statement, the FAA confirmed:
“United Airlines Flight 2166 landed safely at Boise Air Terminal/Gowen Field in Idaho around 2:15 p.m. local time Monday, 24 March 2025, after the crew reported an engine issue. The Airbus A319 had departed San Francisco International Airport and was en route to Bozeman Yellowstone International Airport in Montana. The FAA will investigate.”
Flight Crew and Aircraft Handling
The flight crew’s response adhered to standard emergency protocols, including controlled descent, secure engine shutdown, fuel management, and coordination with air traffic control and ground services. The safe outcome of the event demonstrates the effectiveness of training, aircraft systems redundancy, and emergency planning procedures.
No irregularities were observed in communication with ATC or coordination with airport emergency services.
Weather and Environmental Conditions
At the time of the occurrence, weather conditions in the region were reported as VMC (Visual Meteorological Conditions) with no adverse meteorological phenomena influencing the flight. There was no indication of bird ingestion, foreign object damage, or environmental triggers contributing to the engine anomaly.
Conclusion and Ongoing Investigation
This incident highlights the importance of procedural adherence in the face of in-flight mechanical issues. The crew’s prompt actions ensured the safety of all onboard and enabled a controlled diversion to a suitable airport.
The aircraft remains grounded at Boise while the engine and related systems undergo a detailed technical inspection. The FAA and airline maintenance personnel are actively investigating the cause of the engine issue, with findings expected to determine any further action or maintenance directives.
Disclaimer
This report is based on publicly available information and official statements as of 25 March 2025. While every effort has been made to ensure accuracy, we cannot guarantee the completeness of the information provided. If you are the rightful owner of any referenced materials and wish for them to be removed, please contact takedown@cockpitking.com.
