Flight Details
Aircraft Type: Bombardier CRJ-900LR (CL-600-2D24) Operator: Endeavor Air (operating for Delta Connection) Registration: N313PQ Flight Number: DL4934 Route: Minneapolis–Saint Paul International Airport (MSP), Minnesota to Central Wisconsin Airport (CWA), Mosinee, Wisconsin Date of Incident: 16 April 2025 Total Occupants: Not confirmed; typical CRJ-900 seating approx. 76–80 passengers with 3–4 crew Weather Conditions: Visual meteorological conditions on approach; no adverse weather reported
Introduction
On 16 April 2025, a CRJ-900 operated by Endeavor Air on behalf of Delta Air Lines ingested a bird into one of its General Electric CF34 engines while on final approach to Mosinee’s runway 08. The crew continued the approach and landed safely. No injuries were reported, and the aircraft taxied to the gate without requiring emergency intervention. As of over 40 hours after the event, the aircraft remains grounded for inspection and potential engine maintenance or replacement. The incident is being investigated as a bird ingestion event affecting engine performance, although the engine remained operational during landing.
Sequence of Events
Flight DL4934 was nearing the end of its short regional flight from Minneapolis to Mosinee when the crew experienced a bird strike involving engine ingestion. The strike occurred during final approach, likely between the final fix and the threshold of runway 08.
The aircraft continued on final and landed without deviation or emergency declaration. There were no reports of engine fire, abnormal vibration, or compressor stall, suggesting the engine retained sufficient thrust and integrity to complete the landing.
After vacating the runway, the aircraft taxied normally to the terminal area. No evacuation or medical attention was required, and no passengers reported feeling anything unusual apart from a jolt or brief thump associated with the strike.
The FAA later confirmed the event with a report stating, “AIRCRAFT INGESTED A BIRD IN ONE OF THE ENGINES,” and indicated no information on total persons on board.
Crew & Communication
The flight crew did not issue a Mayday or PAN call, nor did they request priority landing. Their decision to continue the approach and landing indicates that the bird strike did not immediately degrade the engine’s critical performance.
ATC communications remained routine, and the aircraft was cleared to land without delay. Following shutdown, the flight crew coordinated with maintenance and ground staff to report the strike and begin inspection protocols.
Aircraft Systems & Technical Analysis
The CRJ-900 is equipped with two General Electric CF34-8C5 turbofan engines. These engines are designed to tolerate minor bird ingestion events without catastrophic failure, though such impacts can still cause:
Compressor blade damage or deformation Fan blade cracks or imbalance Vibration beyond allowable thresholds Thermal or acoustic liner damage inside the nacelle
Bird ingestion on final approach presents minimal fire risk due to lower engine loads and cooler EGTs compared to take-off. However, post-strike inspections are mandatory, particularly for potential FOD damage or imbalance affecting engine operation.
Following the incident, the aircraft was taken out of service. As of 40+ hours post-landing, N313PQ remains grounded at Mosinee, indicating that the engine is undergoing detailed inspection or awaiting parts for possible fan blade replacement.
Maintenance teams will perform:
Borescope inspection of the engine core and fan section Fan track and balance check Removal and analysis of any biological residue Vibration monitoring test runs
If blade damage or imbalance is confirmed, the engine may be temporarily removed or swapped under the airline’s engine pool agreement.
Passenger Experience & Cabin Conditions
There are no passenger reports of distress or abnormal cabin conditions. Any sound associated with the bird strike would likely have been brief, such as a loud thud or vibration. The impact point was likely the forward fan stage.
Cabin crew were not alerted to any onboard emergency, and passengers disembarked routinely upon arrival. No emergency equipment was deployed, and the aircraft was not towed or externally cooled down.
Emergency Response & Aftermath
There was no emergency activation by the crew. Ground operations at Mosinee remained unaffected. Airport wildlife control was notified post-landing, and any bird remains found on the runway or in the engine inlet area will be documented and sent for species identification.
The FAA has been informed, and a wildlife strike report has been initiated as per federal and airport safety guidelines.
Investigation Status
As this incident involved engine ingestion of wildlife, it falls under routine wildlife hazard reporting rather than a full NTSB investigation. However, data from the aircraft’s quick access recorder (QAR) and engine health monitoring systems will be reviewed by Endeavor maintenance teams.
Key areas under review include:
Bird species identification (to assess potential risk of recurrence) Damage severity classification (minor, major, or catastrophic) Evaluation of flight crew response and aircraft performance metrics
The aircraft will not be returned to service until all airworthiness criteria are confirmed and the affected engine is certified safe for operation or replaced.
Root Cause & Contributing Factors
Primary Cause: Bird ingestion into the engine on short final approach to runway 08 Contributing Factors: Presence of wildlife in the airport’s final approach corridor Time of day or migration conditions (April is peak seasonal activity in many areas) Possible lack of recent bird hazard mitigation in the approach zone
While bird radars and deterrent systems are common at larger airports, regional fields like Mosinee often face challenges in detecting or mitigating birds in flight paths due to open terrain and surrounding woodlands.
Safety Recommendations & Industry Impact
While the event was contained without injury or major damage, bird ingestion continues to be a persistent hazard for regional jets. Recommendations include:
Reinforcement of bird hazard patrols during seasonal migration periods Installation of avian radar systems or field deterrents in high-risk corridors Continued development of fan blade tolerance and damage resistance technologies in regional jet engine design
Delta and Endeavor will likely perform a standard post-incident safety review, and data from this event may inform future enhancements to engine bird ingestion resilience.
Conclusion
The safe landing of Endeavor Air flight DL4934 after ingesting a bird into one of its CF34 engines reflects the robustness of modern engine design and the calm professionalism of the flight crew. With no injuries, no secondary damage, and a controlled landing, the event remains a low-level operational disruption — but one with ongoing implications for wildlife management and engine maintenance.
The aircraft remains grounded for inspection, and the FAA is monitoring follow-up actions.
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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