On September 13, 1993, about 1150 hours eastern daylight time, N42233, a Cessna 182L, operated by the owner/pilot, landed hard and nosed over at a private airstrip in Oxford, Massachusetts. The nose gear collapsed and the airplane was substantially damaged. The certified flight instructor (CFI) and certificated private pilot student were not injured. Visual meteorological conditions prevailed and a flight plan was not filed. The instructional flight departed from Danielson, Connecticut, about 1000 hours and was conducted under 14 CFR 91. According to an FAA aviation safety inspector, the owner of the airplane, a private pilot, was receiving a "check out" in the Cessna 182L by the CFI. During landing, the nose gear collapsed, but the airplane continued to roll on its main gear for 234 feet. An examination of the grass runway revealed initial ground tracks of the main landing gear were found next to a 14-foot ground scar and the separated nose gear. The nose then settled into the ground and the airplane flipped over. The left wing leading edge, right wing strut, vertical stabilizer, and fuselage were damaged. According to the CFI, the private pilot was on a one-quarter mile final approach for runway 14. While 50 feet above the approach end of the runway, an "extremely high sink rate was encountered due to low level wind shear." The CFI took control of the airplane. Ground contact was made "in a slightly tail low attitude" and no stall warning was heard. The nose wheel "immediately broke off approximately 250 feet later." The fractured nose landing gear fork was send to the NTSB Metallurgical Laboratory for examination. The examination did not reveal any evidence of pre-impact deficiencies.