Accident Description
The accident involved an airplane equipped for instrument flight rules (IFR) but not approved for flight into known icing conditions. The pilot initiated a downwind ILS approach and landing.
Icing Conditions
At an altitude of 4,000 feet above mean sea level (MSL), the outside air temperature (OAT) was above freezing. Descending to 3,000 feet MSL, the airplane entered clouds where the OAT was 32 degrees Fahrenheit. Post-accident examination revealed airframe ice on the leading edges of the wings and empennage. The ice measured at least 1/2 inch thick from back to front and one inch across, indicating significant accumulation during the flight.
Pilot Actions
The pilot reported being visual with the runway at 450 feet above ground level (AGL). At that point, the airplane encountered strong downdrafts accompanied by large airspeed fluctuations. The pilot stated that he believed the runway was made and did not consider initiating a go-around. As the airplane approached the runway, it ballooned and neared a stall condition. The pilot then pushed the nose down.
Aircraft Damage
Following the nose-down input, the nose wheel struck the ground and collapsed. The hard impact caused the nose gear failure, but the full extent of additional damage was not specified in the report.