Flight Details
The pilot reported conducting an ILS approach to runway 32 using the autopilot and flight director. The autopilot tracked the localizer while the pilot controlled the descent rate along the glideslope using the pitch command wheel on the autopilot, referencing the command bars and the raw data glideslope needle on the horizontal situation indicator (HSI). The approach appeared normal until the aircraft struck trees approximately 450 feet above airport elevation, about two miles short of the runway. The aircraft came to rest on the localizer centerline. Weather at the airport was reported as a zero-foot ceiling with one-eighth mile visibility.
Investigation Findings
Post-accident investigation determined that the aircraft was equipped with a 1000 A Integrated Flight Control System (IFCS). This system does not provide vertical steering commands in the manner the pilot was operating it; instead, vertical guidance is driven by the pitch wheel. This behavior was not specifically stated in the Pilot's Operating Handbook (POH). The pilot had extensive experience with the 800 series IFCS, which provides the expected steering commands when used similarly.
Examination of the aircraft revealed extensive damage that prevented functional testing of the raw data glideslope needle. Both occupants sustained minor injuries in the accident. A post-crash fire occurred after the aircraft came to rest.
Official Probable Cause
The official probable cause included the following findings:
- The pilot did not maintain proper glidepath during the approach.
- The reason for the failure to maintain the glidepath was undetermined.
- The pilot improperly used flight and navigation instruments.
- Weather conditions were below approach and landing minimums.
- A fire occurred after the collision.