A Boeing 737 Max narrowly avoided disaster during takeoff from London Luton Airport in April 2025 — lifting off with just 162 metres of runway remaining, equivalent to just over two seconds of flight time. Had the aircraft delayed lift-off by another five or six seconds, it risked colliding with a railway line or motorway located immediately beyond the runway’s end.
What went wrong?
The incident involved a charter flight operated by Ascend Airways — a now-defunct UK-based airline that supplied aircraft and crews to other carriers during peak demand. That day, the plane was flying as Wizz Air UK Flight 5411 from London to Athens, carrying 162 passengers, two pilots, and four cabin crew.
Initially, the crew planned to use the full length of Runway 25. But during taxiing, air traffic control suggested starting the takeoff roll from an intermediate intersection to reduce ground distance before entering the runway. The pilots accepted the change — but failed to correctly update critical takeoff speeds (known as ‘V speeds’) in the flight management computer.
These speeds — V1 (decision speed), VR (rotation speed), and V2 (safe climb speed) — are calculated before every flight and depend on aircraft weight, runway length, temperature, wind, and airport elevation. They ensure safe takeoff performance, even in the event of engine failure.
In this case, V2 — the minimum speed required for a safe initial climb — was not properly updated after the revised takeoff point. As a result, the engines were set to deliver only 82.1% maximum thrust, whereas 85.2% was needed for a safe departure from that intersection. The value was perilously close to the 81.4% threshold at which the aircraft would no longer be able to meet safety requirements.
Investigation and disclosure
The UK’s Air Accidents Investigation Branch (AAIB) published its findings on 9 July 2025. The report highlights how procedural oversights — particularly the lack of cross-verification between crew members after a last-minute runway entry change — contributed to the near-miss. The captain had approximately 10,000 total flight hours, including 3,000 on the 737 Max.
Luton Airport is one of London’s busiest airports and handles numerous short-haul and charter operations. The AAIB classified the event as a serious incident, underscoring the importance of rigorous pre-takeoff checks — especially when operational changes occur late in the process.