Undetermined · NTSB CEN11FA431
BOSONETTO THORP T-18 — Howell, MI
| Date | June 29, 2011 |
| Location | Howell, MI |
| Aircraft | BOSONETTO THORP T-18 (amateur-built) |
| Purpose of flight | Instructional |
| Conditions | Day · Visual Meteorological Cond |
| Phase / occurrence | Approach-VFR pattern final Abrupt maneuver |
| Pilot age | 43 |
| Pilot total time | 166 hrs · Low time |
| Time in type | 43 hrs |
| Fatalities | 2 |
Probable cause
NTSB findings
- Personnel issues-Task performance-Use of equip/info-Aircraft control-Pilot - C
- Aircraft-Aircraft oper/perf/capability-Performance/control parameters-Airspeed-Not attained/maintained - C
What happened
The purpose of the accident flight was for the pilot to obtain a flight review in the airplane that he owned. A witness reported seeing the airplane at a higher-than-normal glidepath to the runway and traveling at a slow airspeed while in a forward-slip maneuver. (A forward slip is a flight maneuver used to increase the descent rate, while maintaining airplane pitch and airspeed.) The witness stated that, while the airplane was in the forward slip and losing altitude, it suddenly entered a right spin and descended out of his view. Another witness reported seeing the airplane yawing side-to-side as it approached the runway and then hearing the engine increase to full power as the airplane simultaneously pitched up. The airplane then nosed over and descended into his front yard. A postaccident examination of the airplane revealed no evidence of mechanical malfunctions or failures that would have precluded normal operation. The low-altitude stall/spin encountered during final approach was likely not recoverable. Toxicological testing revealed the presence of several medications in both the pilot and flight instructor; however, it is not likely that they resulted in any impairment.