ZURICH- A United Airlines (UA) Boeing 767-300 operating Flight UA12 from Zurich Airport (ZRH) to Chicago O’Hare (ORD) was compelled to abort takeoff at high speed on June 24, 2025.
The aircraft, carrying 142 passengers and crew members, halted on Runway 16 after the flight crew executed a rejected takeoff at approximately 145 knots. Emergency responders ensured the safe evacuation of passengers, with the aircraft being cleared from the runway nearly four hours later.
United Airlines Flight UA12, utilizing a Boeing 767-300 (registration N684UA), was scheduled to depart Zurich Airport (ZRH) at 09:50 local time heading towards Chicago O’Hare International Airport (ORD).
During the takeoff roll on Runway 16, the flight crew decided to execute a high-speed rejected takeoff at around 145 knots—well above the typical V1 threshold for aircraft of this variety.
The aircraft came to a complete stop just beyond the intersection with Runway 28. Due to hard braking, several main landing gear tires deflated. Passengers were evacuated via mobile stairs directly on the runway, and fortunately, no injuries were reported.
Initial communication between the flight crew and Zurich tower indicated that the pilots believed they could vacate the runway and proceed with post-abort checklists. However, the tower instructed them to hold their position because emergency services were already en route.
While United Airlines has not revealed specific technical details, the airline confirmed to Swiss media outlet 20 Minuten that a “technical issue” led to the rejected takeoff. A spokesperson stated that the airline was actively rebooking affected passengers on alternate flights to minimize further delays.
The aircraft remained on the runway for nearly four hours before being towed to a remote stand. Although Zurich Airport operations were briefly affected, air traffic resumed on alternate runways during the incident response.
Unusual Abort Above V1 Speed
Aborted takeoffs are a standard safety procedure that typically occurs below V1 speed—a critical decision point beyond which takeoff should generally continue. For the Boeing 767-300, V1 speed is usually below 140 knots, depending on various factors including weight and weather conditions.
Data from Flightradar24 indicates that UA12’s abort took place at approximately 143–145 knots, categorizing it among a rare 2% of rejected takeoffs performed at or exceeding 120 knots. Such high-speed aborts are executed only under exceptional circumstances, often linked to critical system failures.
A formal investigation by Swiss aviation authorities alongside airline engineers is expected to ensue.
Related Incidents
An Emirates Airline (EK) flight due to depart from Chennai International Airport (MAA) to Dubai International Airport (DXB) aborted takeoff on June 8, 2025, due to a technical fault discovered during taxiing.
In another instance, a United Airlines (UA) service from Wilmington International Airport (ILM) to Newark Liberty International Airport (EWR) was forced to halt its takeoff roll on May 24, 2025, following a complete engine shutdown just prior to liftoff.
The Emirates (EK) Boeing 777 was preparing for departure at Terminal D1 in Chennai (MAA) when, at about 9:50 AM IST, pilots identified an anomaly while taxiing. The flight crew quickly contacted air traffic control to abort the takeoff for safety reasons.
Emergency teams at Chennai Airport (MAA) arrived promptly. The aircraft was safely towed back to its gate, where Emirates’ technical team began diagnostics. Despite initial troubleshooting efforts, the fault persisted. By 12:20 PM IST, the flight was canceled, impacting 312 passengers onboard.
In a similar occurrence two weeks prior, United Airlines (UA) faced a comparable situation at Wilmington International Airport (ILM). The aircraft, already delayed for over five hours, commenced its takeoff roll when the pilots abruptly ceased the plane’s forward momentum. Passengers later discovered that one engine had failed, necessitating their return to the gate and rescheduling of the flight for the following morning.
Safety Procedures and Emergency Response
Both incidents fall under the category of rejected takeoffs (RTOs), a crucial phase that requires flight crews to act decisively prior to reaching V1—the juncture at which takeoff becomes irreversible. Aviation safety standards dictate that pilots must abort takeoff if any serious fault is detected before this threshold.
In this United Airlines (UA) case, the captain reportedly mentioned a generator failure associated with essential hydraulic systems. Although rare, such failures can arise from various issues, including:
- Compressor stalls
- Bird strikes
- Fuel system leaks
- Foreign object debris (FOD)
- Component detachment
- Fire or overheating in engine compartments
The aircraft involved in these incidents—widebody long-haul jets—are designed to manage engine failures and feature multiple system redundancies to ensure the safety of passengers and crew during high-stress scenarios.
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Based on an article from aviationa2z.com: https://aviationa2z.com/index.php/2025/06/25/united-pilots-aborts-takeoff-at-zurich-airport/?utm_source=rss&utm_medium=rss&utm_campaign=united-pilots-aborts-takeoff-at-zurich-airport
