On November 20, 1985, at 1944 UTC (local time +1), the Boeing B-747-231B (9V-SQQ) airliner operating flight SQ 23 from Amsterdam landed on runway 14 at Zurich Airport, which was heavily iced. It was unable to slow down sufficiently and did not stop until 83 meters past the end of the runway. The incident occurred at night; the damage was minimal. Cause The runway overrun was due to insufficient deceleration of the aircraft on the ice. Factors that played a role: – The airport did not take all necessary measures to quickly de-ice the runways, which were known to be covered in ice. – The crew did not realize the critical condition of the runways due to: – Incomplete and late reporting of their deteriorating condition, and – The crew’s insufficient experience in winter conditions. – The crew’s behavior was not optimal concerning the control of the runway condition and the choice of braking process.