What happened
The pilot was conducting an instrument landing system (ILS) approach into Nashville when the aircraft encountered severe weather conditions. Approximately twenty minutes of the thirty-minute flight had been spent flying within clouds. An air carrier flight that landed approximately ten minutes earlier reported encountering significant amounts of rime ice, and a Beech 99 that landed two minutes ahead reported no issues with the approach.
The freezing level at Nashville was reported to be at 900 feet mean sea level at 17:50 CST. During the approach, the aircraft encountered an extreme downdraft. The vertical speed indicator showed a change from approximately 500 feet per minute to about 1,200 feet per minute descent rate.
In an attempt to recover, the pilot applied full power, increased pitch attitude, and reduced the flap setting from 25 degrees to 10 degrees. However, these actions were insufficient to arrest the sink rate. The aircraft subsequently struck two approach lights and a localizer platform approximately one-quarter mile from the runway threshold.
The investigation
The Piper PA-32RT-300 Pilot's Operating Handbook specifies that flaps should be retracted slowly only after a positive climb rate is established when initiating a go-around from a landing approach. The pilot's actions to reduce flap angle while still in a high sink rate condition may have contributed to the inability to regain altitude.
Findings
The accident occurred during an instrument approach in conditions conducive to icing. The aircraft encountered severe turbulence and downdrafts that exceeded the climb performance capability of the aircraft at the given configuration and weight. The pilot's decision to reduce flap angle prior to establishing a positive climb rate, as per standard go-around procedures, likely hindered the recovery effort.