Incident Overview
A pilot was practicing night instrument landing system (ILS) approaches in visual meteorological conditions when the aircraft collided with an object during the third practice approach. The pilot executed a missed approach and returned to the base airport, where an inspection revealed that the left wing had contacted a tree.
Approach Data
Air traffic communications and radar data indicated that the aircraft was established on the localizer during all three approaches. However, on the first approach, the aircraft descended to 500 feet below the minimum descent altitude (MDA) of 2,000 feet when crossing the final approach fix (FAF). On the second approach, it was 900 feet below the MDA at the FAF. The FAF is identified via a radial from a VOR.
During the third approach, radar data showed the aircraft tracking on the localizer but continuing to descend to 500 feet approximately 1.7 nautical miles prior to the FAF. Shortly after that point, a climb was observed.
Equipment Testing
Testing of the airport approach equipment revealed normal operation. Testing of the aircraft's #1 ILS system found that the glide slope had extremely low sensitivity and could not pick up a signal. The localizer was within tolerance but was off by one and a half dots.
Safety Pilot Observations
The safety pilot reported that he never saw the airport during the third approach and thought that everything was normal.
Probable Cause
The source does not provide a stated probable cause.