A B787-9 departing runway 26L at Munich for Hanoi used the full 4,000 m runway without reaching take-off speed. It rotated at about the far threshold (08R) and lifted off from the grass roughly 240 m beyond the runway end, past the 60 m clearway. The tail and both main gears struck the approach lighting, and 20 lamps were damaged. The fuselage was substantially damaged by a tail strike.
The crew declared a PAN, climbed to FL90 and dumped 62 t of fuel. They then flew two gear-down low passes so ground personnel could inspect the gear. They landed on 26R about two hours after departure, with four left main gear tyres damaged. All 287 people on board (4 pilots, 12 cabin crew and 271 passengers) disembarked by stairs uninjured.
The crew had calculated take-off speeds of V1 169 kt, Vr 175kt and V2 180 kt for a take-off mass of 240,857 kg, close to the aircraft's maximum of 247,207 kg. The temperature was 33°C and Munich's elevation is 1,487ft.
Three seconds after TOGA was engaged, the recorders captured brake pedal inputs from the left seat. Tyre marks were later found on the runway abreast of taxiway B4, and braking continued intermittently throughout the take-off run, with brake commands peaking at about 27% on the left side and 17% on the right. As the aircraft accelerated, the airspeed stalled at around 168 kt for about 18 seconds, never reaching V1 while the aircraft was on the ground. With the runway running out, the PM increased thrust manually by only 1% N1. A second later, the PF began rotation at 163 kt, below Vr.
The aircraft reached V1 once it was 11 ft above the ground, and V2 at 76 ft. Just after lift-off, pitch reached 12.2° and the angle of attack 14°, triggering the automatic stall protection, which fully extended the slats. The TOGA mode was then activated again, and a tail strike was recorded.
There were four pilots on board. The PF for take-off was a 64-year-old captain with 27,182 hours. The nominated PIC, a 55-year-old, was in the left seat. He took over as PF at 9,000 ft and flew the passes and the landing.
The flight data were recovered, but the cockpit voice recording of the take-off was overwritten because the recorder kept only the last two hours. The BFU has the Brake System Control Units and the Electric Brake Actuator Controllers for detailed examination.
No findings, causes or recommendations have been issued yet. The central open question is why braking was recorded throughout the take-off roll: whether it came from unintended pedal input by the PF, a brake system fault, or some combination of the two. The report also leaves unexplained why the crew did not reject the take-off or add more thrust.
Photo source: Mirage3RZ,CC BY-SA 4.0, viaWikimedia Commons