On July 15, 2005, about 1354 eastern daylight time, a Mooney M20M, N355RZ, piloted by a commercial pilot, sustained substantial damage on impact with terrain during a forced landing at the White Cloud Airport, near White Cloud, Michigan. The flight encountered an in-flight loss of engine power. The personal flight was operating under 14 Code of Federal Regulations Part 91. Visual meteorological conditions prevailed at the time of the accident. An instrument flight rules (IFR) flight plan was on file and was activated. The pilot reported no injuries. The flight originated from the Gerald R. Ford International Airport, near Grand Rapids, Michigan about 1317, and was destined for the Brainerd Lakes Regional Airport, near Brainerd, Minnesota. The pilot's accident report stated: This is to explain the facts of the engine failure of Mooney N355RZ. The Mooney Bravo was left at Grand Rapids (KGRR) airport for engine repair for a rough running engine. The airplane was inspected and left for repair to have three cylinders sent in to be repaired. On Friday July 15th, 2005, I drove to (KGRR) to pick the aircraft up and return it to Bismarck, ND. The mechanics where still working on the engine so I waited until mid-afternoon until the repairs [were] finished. In the meantime I filed IFR and checked weather with Lansing [Flight Service Station]. I planned my route of flight direct Beaver Island, and then direct Brainerd, MN. I planned this route to avoid flying over the widest part of Lake Michigan. I taxied out to runway 8R at (KGRR) did my run-up and was cleared for take off. I filed for 14,000 feet [above mean sea level]. Tower had me runway heading to 4000 feet and then to contact departure. Departure had cleared me direct and up to 14,000 feet. At that point I had the climb power set and the auto-pilot flying [global positioning system] GPS direct to Beaver Island with all engine instruments reading normal. Climbing through 9,000 feet I noticed that my climb performance had been reduced substantially. I then noticed that I had a serious problem. The [oil] temp was then red-lined, the oil pressure low, and power drastically reduced. At that point I disconnected the autopilot and lowered the nose to avoid a stall and attempt to cool the engine. I contacted [Minneapolis] center and reported the problem. The controller asked if I was declaring an emergency, and I said yes, and requested vectors to the closest airport. At this point I could see oil coming down the left window. He turned me heading west and gave me the identifiers for White Cloud airport. I put the identifiers in the GPS and was trimming the aircraft to conserve altitude. Then the aircraft began to shake extremely rough, making me wonder what was going to happen next. I still had some power but was wondering how long until the engine would totally fail. I had a scattered layer around 3-4,000 feet that I descended through. I got visual on the airport. At that point airspeed and altitude where minimal and the power reduced to almost nothing. The power then seized to nothing, I adjusted the manifold and got no response. The terrain around the airport was heavily congested with trees, houses, and power lines. I aimed the aircraft towards mid field and figured if I put the aircraft down without stalling or hitting trees I would walk away. At that point I was low, out of altitude, out of power and [decided] to take the side of the runway at [White Cloud]. I put the aircraft down on the uneven terrain at the south end of runway 18-36 at White Cloud. The aircraft came to a stop promptly. I then opened the door and exited the aircraft. Local authorities then arrived. I could then see the stream of oil going down the side of the fuselage. A Federal Aviation Administration Inspector along with an airplane mechanic examined the wreckage. The mechanic found a disconnected oil line. The disconnected oil line went to the cylinder valve guides for cooling. The other end of the line was connected at the outlet of the oil cooler from where the oil is supplied to the valve guides. A representative of the fixed base operator at KGRR stated that three cylinders were removed and replaced. During the engine's operational check, no oil leaks were noted. The technician that performed the work also inspected the work. The representative stated that oil would begin to flow from the disconnected line once the engine warmed up and the vernatherm opened. The representative stated that human factors were also involved, as there was pressure to get the work done as the owner requested. The representative stated that secondary inspectors will be used whenever possible and that the entire maintenance staff will be trained on human factors.