N444TTSmith AEROSTAR 601P

Before approach to the destination airport, the pilot checked the wind at a nearby airport which was reported to be at 20 knots with gusts to 25 knots. Additionally, the on-board global positioning system (GPS) receiver depicted the wind from 010 degrees at 12 knots. He executed a GPS approach to runway 28, maintaining 120 knots with 20 degrees of flaps extended, and before landing noted the wind sock was not fully extended. He extended full flaps about 1 mile from the runway, and slowed to 100 knots, then crossed the threshold at 80 knots. The airplane touched down about 75 knots on the wet runway, and he "gently applied the [brakes] on touchdown. I was unable to do hard [braking]." The airplane started hydroplaning approximately 1,000 feet before the end of the runway. Unable to stop, the airplane rolled past the departure end of the runway, where the nose landing gear traveled into a small depression causing it to twist. The forward pressure bulkhead was later found to be cracked. The pilot reported there was no mechanical failure or malfunction. The airport is equipped with an automated weather observing system (AWOS). A total of 12 observations were recorded for the approximate time of the accident (1130 local, or 1630 UTC). Review of the 12 observations indicated the wind was from 230 degrees at 8 knots with gusts to 18 knots.