Munich's runways are 4,000 metres long. On 15 August 2026, a fully loaded Vietnam Airlines Boeing 787-9 used all of it, and then some. Flight VN34 to Hanoi left the ground from the grass beyond the end of the runway, clipped the approach lights with its tail and main gear, and climbed away with four shredded tyres.

For six weeks the question was why. On 28 September, Germany's Federal Bureau of Aircraft Accident Investigation (BFU) published its interim report, and the answer is stranger than anyone expected. During the take-off run, the brakes were being applied.

A Take-Off That Would Not Accelerate

The 787 was heavy. AeroTime reported a take-off weight of around 240 tonnes, close to the aircraft's 247.2-tonne maximum, which is normal for a long-haul flight to Vietnam. The weather was good. The captain, a 64-year-old with more than 27,000 flying hours according to Reuters, was the pilot flying.

According to the BFU's flight data, the brakes were activated shortly after the take-off run began. Later in the run there was a second braking event, moments before rotation. One Mile at a Time and AirLive, both summarising the report, say the inputs came from the brake pedals at the captain's seat, with the brake control units commanding up to 27 percent braking on the left and 17 percent on the right.

That is not full braking. It is enough to rob a heavy jet of the acceleration it needs. Reuters reports that the airspeed sat at around 168 knots for roughly 18 seconds before the first officer pushed the thrust up further.

Airborne From the Grass

By then the runway was running out. The crew rotated at about 163 knots, roughly 12 knots below the speed they had calculated. The aircraft did not lift off on the paved surface. According to aeroTELEGRAPH's reading of the report, it left the ground in the grass about 240 metres beyond the runway end.

On the way up, the tail and the main landing gear hit the approach lighting system. Twenty light fixtures were struck. Four tyres on the left main gear were damaged, and the rear fuselage took the kind of scrape that no airline ever wants to see on a widebody.

The crew then did everything right. They climbed away, jettisoned about 62 tonnes of fuel, flew low passes so the gear could be inspected from the ground, and landed back at Munich about two hours after departure. Nobody on board was hurt.

Juan Browne of the blancolirio channel walks through the BFU interim report on VN34.

Pilot or Machine?

This is the question the interim report does not answer. The 787 uses electrically actuated wheel brakes, and the BFU has secured brake system components for testing. Aviation Week reports that the investigation is focusing on the brake system control units and the electric brake actuator controllers.

The other possibility is a human one. On the 787, as on most airliners, the wheel brakes are applied by pressing the top of the rudder pedals. Investigators have not said which it was. They may not have the cockpit audio to help them. Reuters reports the cockpit voice recording of the take-off had been overwritten, because the recorder kept running for more than two hours after the take-off.

Aviation Week reports that the BFU has classified the event as an accident. A final report will follow. Until then, VN34 stands as a reminder that a runway is only long enough if the aircraft is actually allowed to accelerate on it.

Sources: BFU interim report as reported by Reuters, aeroTELEGRAPH, One Mile at a Time, AirLive, AeroTime, Flightradar24, Aviation Week