Korean Air Flight 8702 departed Tokyo-Narita at 16:50 for a flight to Seoul, scheduled to arrive there at 19:20. Bad weather, including heavy rainfall, at Seoul forced the flight crew to divert to Cheju. The aircraft took off from Cheju at 21:07 for Seoul. The flight was cleared to land on runway 14R with a crosswind component as the wind was from 220 degrees at 22 knots. After touchdown the no. 1 engine thrust reverser did not deploy because the no. 1 engine power lever’s position did not allow the reverser to be deployed. The airplane ran off the side of the runway onto soft ground. Part of the main undercarriage separated after traversing a drainage ditch. The KCAB’s investigation determined that the accident was caused by the captain’s misuse of the thrust reverser during the landing roll and his confusion over crosswind conditions.