On May 28, 2008, about 1151 Pacific daylight time, a Cessna 172M, N21134, sustained substantial damage after impacting powerlines and terrain during an attempted go-around at the Big Bear City Airport (L35), Big Bear City, California. The certificated private pilot, the sole occupant, sustained serious injures. Visual meteorological conditions prevailed for the cross-country flight, which was operated in accordance with 14 Code of Federal Regulations Part 91, and a flight plan was not filed. The flight departed Zamperini Field (TOA), Torrance, California, about 1020, with L35 as its destination. In a statement provided by the pilot, upon arriving at L35 she checked the automated weather report and utilized the vertical slope indicator lights (VASI) during her approach to Runway 26. The pilot reported that when she was about 80 feet over the runway she believed she experienced a severe windshear, which blew her off course to the left. The pilot further reported, "...at this point my airspeed was too slow, so I put up flaps and full throttle and proceeded to do a go-around. At this point my plane would not climb." The pilot stated that she could not put the airplane's nose down in fear of impacting trees, homes, or powerlines; however, she was able to establish enough of a climb to get over powerlines and aimed the airplane to pass between two tall trees. The pilot revealed that the airplane subsequently caught a powerline with one wheel, "...and then I guess I crashed between trees and two houses, landing on a boat." According to a pilot who was waiting in the runup area to depart, he initially observed the accident airplane on final approach. The witness stated that the airplane crossed over the [Runway] 26 numbers about 50 feet above ground level (agl), "...slowing quickly but not descending. The airplane continued at that altitude, slowing even more with an increasingly nose up attitude. I couldn't believe the plane was still airborne at that slow speed, which I thought was about 30 miles per hour." The witness further stated that he thought the airplane was going to stall and drop 40 to 50 feet onto the runway, but it remained airborne and began banking sharply to the left, then right; he estimated the bank angle to be 45 degrees at one point. The witness revealed that the airplane continued the "wild swings" back and forth until midfield, when it banked sharply to the left in a steep nose up attitude, remaining at 40 to 50 feet agl. The witness reported that he transmitted "Go around," and a few seconds later the accident pilot replied, "I'm trying." The witness stated that he lost sight of the airplane as it crossed in front of the airport terminal building. A Federal Aviation Administration aviation safety inspector, who responded to the accident site, reported that the airplane had impacted a set of transmission wires prior to impacting the eve of a house and a boat. The airplane subsequently came to rest in an upright position between two houses and partially on the boat. There was no postcrash fire. No anomalies were reported with the airplane prior to the flight, and the FAA inspector reported that all airplane components necessary for flight were accounted for at the accident site. When asked during an interview by the FAA inspector how many times she had flown in to L35, the pilot stated that she had flown into L35 on two previous occasions. When the inspector asked the pilot if she had returned the mixture contol to the full rich position prior to landing the pilot replied, "No, it wasn't, [be]cause you have to keep your mixture lean because you're up so high." At 1151, the L35 Automated Weather Observing System (AWOS) reported wind 240 degrees at 9 knots, gusts to 12 knots, visibility 10 miles, sky clear, temperature 53 degrees Fahrenheit, dew point 16 degrees Fahrenheit, and an altimeter setting of 30.11 inches of Mercury. The airplane's Pilot's Operating Handbook (POH) states that a balked landing is performed by reducing the wing flap setting to 20 degrees immediately after full power is applied. If the flaps were extended to 40 degrees, the reduction to 20 degrees may be approximated by placing the flap switch in the UP position for two seconds and then returning the switch to neutral. If obstacles must be cleared during the go-around climb, leave the wing flaps in the 10 degree to 20 degree range and maintain a climb speed of 65 to 75 miles per hour (MPH) until the obstacles are cleared. Above 3,000 feet, lean the mixture to obtain maximum RPM. After clearing any obstacles, the flaps may be retracted as the aircraft accelerates to the normal flaps-up climb speed of 80 to 90 MPH.