On December 2, 2007, approximately 1845 Pacific standard time, a Cessna 551, N551GF, departed the runway during the landing roll at Coeur d'Alene Air Terminal (COE), Coeur d'Alene, Idaho. The airline transport pilot, airline transport second pilot, and six passengers were not injured. The airplane was substantially damaged. CCM Aviation L.L.C. was operating the airplane under 14 Code of Federal Regulations Part 91. Visual meteorological conditions prevailed for the cross-country personal flight that originated from Henderson, Nevada, approximately 3 hours before the accident. An instrument flight rules flight plan had been filed and activated. The pilot reported to a Federal Aviation Administration (FAA) inspector that he landed on runway 23. He said upon touchdown the airplane began hydroplaning to the right. He added power to the right engine to try and stay on the centerline, and regain directional control. The airplane continued drifting right until it struck a concrete pad that was supporting a lighted runway sign. The airplane came to rest approximately 90 degrees to the centerline, and 10 to 15 feet off the runway. Post accident examination of the airplane by an FAA inspector revealed that the nose landing gear separated from the airplane and impacted the leading edge of the left wing, which created an indentation and hole. Additionally, the nose gear wheel well was structurally deformed, which required a major repair to rectify. The pilot said that on approach to the airport, he was told that there was 3/4 inch of snow on the runway, and the wind was from 170 to 190 degrees at 16 knots, gusting to 22 knots. He was also told that braking had been tested by a vehicle, and was reported to be "NIL" on runway 01/10 and "POOR" on runway 05/23. After landing, he discovered that the runway had 2 1/2 inches of slush on it.