Piper PA-32R-300 N5677V accident near Bloomington, Indiana

Probable cause

The pilot’s failure to follow the instrument landing system (ILS) course guidance, which resulted in the pilot’s loss of airplane control during the instrument approach. Contributing to the accident was the presence of turbulence and low-level wind shear.

NTSB analysis

After departure, the flight proceeded on course and was issued radar vectors for an instrument landing system (ILS) approach at the intended destination airport. The flight tracked inbound along the ILS localizer; however, after it passed the final approach fix the airplane’s flight path appeared to become unstable. The airplane subsequently entered a right turn about 2.25 miles from the runway and impacted a wooded hillside absent of ground lighting about 2 miles south of the airport. The impact path was oriented nearly perpendicular to the runway extended centerline. Postaccident airframe and engine examinations did not reveal any anomalies consistent with a preimpact malfunction or failure.

Airplane airspeed varied from about 90 knots to 155 knots as the flight neared and then intercepted the ILS approach course. Airplane vertical speed during this timeframe ranged from a 1,500 feet-per-minute (fpm) climb to a 1,000-fpm descent. The airplane’s airspeed was about 128 knots as it crossed the final approach fix and during the final 60 seconds of the flight was about 118 knots. The airplane remained in a descent that exceeded 1,000 fpm over the final 30 seconds of the flight.

A review of available weather data indicated the pilot was likely in instrument meteorological conditions and precipitation and likely encountered turbulence with moderate or greater low-level wind shear during the approach.

The Pilot’s Operating Handbook recommended an indicated airspeed of 75 knots on final approach. When established on a 3° glideslope with a 90-knot groundspeed, an airplane will descend at 450 fpm. The FAA defined a stabilized approach as one that maintains a constant angle glidepath toward a predetermined point on the landing runway.

It is likely that an inadvertent encounter with turbulence and low-level wind shear resulted in an unstable approach and subsequent loss of control. The presence of instrument meteorological conditions and dark night lighting conditions when the airplane did emerge from the clouds further hindered the pilot’s efforts to remain on the approach or to execute a missed approach.

Text from the NTSB. Open the NTSB docket for CEN22FA080 for the full record.