The Jetstream aircraft was scheduled to perform a charter flight from El Cara¤o Airport (SKUI), in the city of Quibd¢, to Jos‚ Celestino Mutis Airport (SKBS), in the municipality of Bah¡a Solano, Colombia. The landing took place apparently in a normal way, and as the speed decreased below 70 knots, the crew activated the reversers and selected the propellers in “taxi” position. The crew noticed that the plane was beginning to drift to the left side of the the runway. The pilot unsuccessfully tried to control the deviation with differential braking and with the nose wheel steering control system. The crew was unable to correct the deviation due to the condition of the runway which was wet and highly contaminated. The plane left the runway to the left side, moved over the safety zone and finally stopped 115 meters from the threshold of runway 18 and approximately 9.5 meters from the edge of the runway, in muddy and uneven terrain with an approximate heading of 343ø. All occupants left the aircraft unharmed. There was no fuel leakage; there was no fire. Probable cause(s): Lateral runway excursion as a result of loss of directional control of the aircraft during the landing run, caused by the condition of the runway, contaminated with slurry and waterlogging, conditions which produced viscous hydroplaning. Contributing factors Precarious condition of the runway of the Bah¡a Solano airfield, which has an irregular surface, with two types of bearing material, concrete and asphalt, accumulated humidity and the presence of slurry in all its extension, which makes it slippery. Deficient conditions in the safety area of the Bah¡a Solano airfield, which presents unevenness and flooding, which contributed to the damage of the aircraft during the runway excursion. Lack of planning on the part of the operator for not carrying out a complete risk analysis for operating on a runway in precarious conditions such as that of Bah¡a Solano. Lack of situational awareness of the crew, to anticipate and correct control difficulties of the aircraft during the landing run.