Flight Details
Aircraft Type: Boeing 737-824 Operator: United Airlines Registration: N27213 Flight Number: UA2325 Route: Denver International Airport (DEN), USA to Edmonton International Airport (YEG), Canada Date of Incident: 13 April 2025 Total Occupants: 159 (153 passengers, 6 crew) Weather Conditions: Visual meteorological conditions; winds northwesterly, light to moderate; no convective activity reported
Introduction
A United Airlines Boeing 737-800 encountered a serious in-flight emergency on 13 April 2025, shortly after takeoff from Denver International Airport. While climbing out from runway 34L, the aircraft suffered a failure of its right-hand engine, accompanied by a fire warning. The crew immediately declared a Mayday, conducted emergency procedures, and safely returned to Denver following a short holding pattern. All passengers and crew were unharmed. The incident has been classified as a serious engine malfunction, pending investigation.
Sequence of Events
United flight UA2325 departed Denver at approximately midday local time, bound for Edmonton, Alberta. The aircraft, a twin-engine Boeing 737-800, lifted off from runway 34L and climbed normally until shortly after initial contact with departure control.
Within minutes of becoming airborne, the flight crew declared a Mayday, reporting the loss of the number two engine (right-hand CFM56). Concurrently, the crew notified controllers of a fire indication associated with the engine or the right wing area. ATC cleared the aircraft for an immediate return to the airport.
Rather than initiate a direct approach, the flight crew requested and were granted a holding pattern to complete engine fire checklists and assess the condition of the aircraft. The aircraft maintained controlled flight throughout, and no onboard systems other than the affected engine were reported compromised.
After approximately 40 minutes airborne, the aircraft returned to Denver and landed safely on the same runway from which it had departed, runway 34L. Emergency services were positioned along the runway but were not required to intervene after landing. The aircraft vacated the runway and taxied under its own power.
Crew & Communication
The flight crew’s response to the emergency was rapid and aligned with emergency protocols. A Mayday was declared immediately after the engine failure and fire indication, ensuring priority handling from ATC.
Voice communications remained continuous and professional throughout. The request to enter a hold, rather than rush the approach, suggests a calculated decision to manage the emergency methodically and reduce risk during the approach and landing phase.
The cockpit crew have not been named publicly, but their actions reflect appropriate crew resource management and adherence to United’s emergency checklists. There were no indications of crew confusion, miscommunication, or procedural errors.
Aircraft Systems & Technical Analysis
The Boeing 737-800 involved in the event, tail number N27213, was equipped with two CFM56-7B series engines. This powerplant is standard for the 737 Next Generation series and has a strong operational safety record.
According to United Airlines, a wildlife strike is suspected as the initiating factor for the engine failure. This aligns with eyewitness accounts from ground observers who reported seeing three separate bursts of flame from the right engine during the climb phase.
The engine’s fire detection system was triggered, although the presence of an actual fire has not been formally confirmed. It is unclear whether the crew discharged the engine fire extinguishing agent or if the fire extinguished naturally following engine shutdown. The aircraft was not reported to have suffered any external fire damage, and no evidence of an uncontained failure was visible externally after landing.
The aircraft remained grounded in Denver for over eleven hours following the event, and was undergoing engineering inspection at the time of writing. A full teardown of the right engine, including borescope inspection of hot section components, will likely be performed.
Passenger Experience & Cabin Conditions
No injuries or cabin distress were reported. Although the fire was visible externally, it is not clear whether passengers could observe the event from inside the cabin.
Standard safety briefings and communication from cabin crew would have been carried out during the holding phase, although no evacuation or brace procedures were required. The aircraft made a normal approach and landing, and all passengers disembarked via airbridge or mobile stairs.
There were no emergency oxygen deployments, cabin smoke, or other abnormal conditions reported inside the passenger compartment.
Emergency Response & Aftermath
Denver International Airport dispatched emergency response units in accordance with established protocol for an in-flight fire report. Fire and rescue vehicles were stationed along the runway and taxiways during the aircraft’s return, but no active firefighting or intervention was required.
Following the safe landing, the aircraft was taxied to a remote stand for inspection. Passengers were transferred to the terminal and later rebooked on an alternative aircraft.
United Airlines dispatched a replacement Boeing 737-800 (registration N79541) to resume the service to Edmonton. The onward flight was completed with an estimated delay of three hours.
Investigation Status
As of the time of writing, no federal investigation team has been deployed to the site. The Federal Aviation Administration is overseeing the internal investigation by United Airlines, consistent with the level of risk and the aircraft’s safe outcome.
Key areas of focus include confirmation of a bird strike, inspection of the engine’s hot section, examination of fire detection loops, and assessment of any recent maintenance actions that may have affected the powerplant.
Air traffic control recordings, flight data monitoring, and crew interviews will also contribute to determining the sequence of failure and response actions.
If confirmed, a bird ingestion into the engine may prompt additional inspections at Denver International, particularly regarding airport wildlife hazard mitigation procedures.
Root Cause & Contributing Factors
Although formal findings are pending, the suspected bird strike aligns with visual evidence of flame emission from the right engine and the immediate fire warning. Wildlife ingestion is a known hazard during the takeoff phase, particularly at airports located near open terrain or migratory routes.
The flight crew’s decision to hold rather than immediately return supports the assumption that the fire was either suppressed or ceased following shutdown. This decision prevented further risk during approach and allowed for safe single-engine landing under standard operating parameters.
Environmental factors—such as seasonal bird movement near Denver—may also be considered contributing conditions.
Safety Recommendations & Industry Impact
The incident reinforces the need for continuous wildlife hazard monitoring and mitigation at large commercial airports, especially during high-traffic and migratory periods.
It may also prompt renewed industry discussion around improved in-cockpit bird strike detection tools and AI-assisted threat mapping during departure routing.
United Airlines is expected to audit maintenance records, crew training compliance, and checklist execution, although early indicators suggest exemplary performance from the flight crew and technical systems.
No airworthiness directives or manufacturer bulletins have been issued at this stage, pending formal analysis of engine components.
Conclusion
The United Airlines UA2325 incident serves as a timely reminder of the persistent threat posed by wildlife strikes, even in clear daylight conditions and routine operations. The event was professionally managed by a well-trained crew and underscores the resilience of the Boeing 737-800 in single-engine scenarios.
The aircraft returned safely without injuries or collateral damage. Attention now turns to the investigation, which will seek to confirm the root cause and determine whether mitigation measures at Denver International require strengthening.
Disclaimer
This article is based on publicly available information and reports at the time of writing. While every effort has been made to ensure accuracy, we cannot guarantee the completeness of the information provided.
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