Mechanical & Engine Failure · NTSB CEN18FA023
BEECH V35B — Alva, OK
| Date | November 4, 2017 |
| Location | Alva, OK |
| Aircraft | BEECH V35B |
| Purpose of flight | Instructional |
| Conditions | Day · Visual Meteorological Cond |
| Phase / occurrence | Approach Part(s) separation from AC |
| Pilot age | 39 |
| Pilot total time | 231 hrs · Low time |
| Time in type | 1 hrs |
| Fatalities | 2 |
Probable cause
NTSB findings
- Personnel issues-Task performance-Use of equip/info-Aircraft control-Instructor/check pilot - C
- Personnel issues-Task performance-Use of equip/info-Aircraft control-Pilot - C
- Aircraft-Aircraft oper/perf/capability-Performance/control parameters-Pitch control-Design - C
- Aircraft-Aircraft oper/perf/capability-Performance/control parameters-Descent rate-Not attained/maintained - C
- Personnel issues-Action/decision-Info processing/decision-Understanding/comprehension-Pilot - C
- Personnel issues-Action/decision-Info processing/decision-Understanding/comprehension-Instructor/check pilot - C
- Aircraft-Aircraft structures-(general)-(general)-Inadequate inspection - C
- Personnel issues-Action/decision-Info processing/decision-Identification/recognition-Pilot - C
- Personnel issues-Action/decision-Info processing/decision-Identification/recognition-Instructor/check pilot - C
- Personnel issues-Task performance-Inspection-Preflight inspection-Pilot
What happened
The private pilot had recently purchased the Bonanza airplane, which he and an experienced flight instructor were using to conduct his first training flight in a Bonanza. During a visual approach, the engine's left cowling opened. According to the pilot, who initially survived the accident, the flight instructor assumed control of the airplane. Based on video from home surveillance cameras, the descent rate for the approach increased to about 1,000 ft per minute about 100 ft above ground level. About 7 seconds later, the airplane impacted trees and a power line located 1/2 mile from the runway threshold.
The airplane was one of three Bonanza airplanes modified with a Robertson Short Takeoff and Landing (STOL) system. The flight characteristics for this modification included a strong pitch-down force while extending the flap from 15° to 30° position, which is greater than in Bonanzas without this STOL system. The investigation could not determine if the pilot or flight instructor was aware of this unique flight characteristic, which was not described in the STOL certification information.
The pilot had compiled a list of airplane discrepancies, which included "cowling latch - pilot's side rear spring." It is likely a latch for the left engine cowling opened in flight because it was not properly secured during the preflight. The flight instructor and pilot were likely distracted by the open engine cowling and did not expect the strong pitch-down force during flap extension, which resulted in a high descent rate on short final.