100-TONNE TAKEOFF WEIGHT ERROR CAUSED B777 TAIL STRIKE AT MILAN
On 9 July 2024, LATAM Boeing 777-300ER PT-MUG struck its tail during takeoff from Milan Malpensa after departing with performance data based on a 100-tonne weight error.
Investigators found the crew used 228.8 tonnes instead of the correct 328.4 tonnes when calculating takeoff performance for São Paulo.
The incorrect weight was verbally confirmed and entered into both pilots’ electronic flight bags. Since both devices used the same wrong figure, cross-checks matched and masked the error. No comparison was made with the loadsheet or FMC data.
The consequences were immediate:
• Reduced thrust setting
• Invalid performance solution (“V SPEEDS UNAVAILABLE”)
• Rotation and V-speeds far below safe values
Correct speeds should have been approximately:
V1 ≈ 172 knots
VR ≈ 181 knots
Instead, rotation began around the mid-140 knot range.
The aircraft pitched to 8.3° nose-up within seconds. Tail-strike protection activated, but the tail contacted the runway at about 160 knots.
By then the aircraft had passed the (incorrectly calculated) V1, making a rejected takeoff impossible.
A third pilot in the cockpit called for full TOGA thrust roughly 12 seconds after rotation began. The aircraft finally lifted off at 178 knots with only ~800 metres of runway remaining, crossing the opposite threshold at just 155 feet.
The crew declared an urgency, dumped 72 tonnes of fuel and returned safely. All 398 occupants were unharmed.
The event was later reclassified from serious incident to accident due to structural damage found during inspection.