History of Flight
On July 16, 2021, at approximately 0840 Pacific daylight time, a Beechcraft V35B, registration N112TW, was destroyed in an accident near Angwin Airport-Parrett Field (2O3), Angwin, California. The airplane was operated as a personal flight under 14 CFR Part 91. Radar track data showed the airplane departed French Valley Airport (F70) in Murrieta, California, and climbed southwest, then turned left to the northwest to about 9,000 ft msl, maintaining that altitude for most of the flight. About two hours later, the airplane descended from 9,000 ft msl as it entered a left downwind for runway 16 at 2O3. It made a wide left base turn to final, overshot the approach, then reacquired the runway heading and landed. Witnesses reported the airplane cleared the first tree line at the departure end of the runway, then began to pitch up, the left wing dropped, and the nose dropped toward the ground. They lost sight of the airplane behind a hill and saw smoke shortly afterward.
Personnel and Aircraft Information
The pilots' logbooks were not recovered. The airplane was equipped with a throw-over-type control column for elevator and aileron control, as described in the Beechcraft Bonanza V35, V35A, and V35B Pilot's Operating Handbook (POH). The POH balked landing procedure includes power to full throttle, 2700 RPM, airspeed 70 kts/81 mph until clear of obstacles, flaps up, landing gear up, and cowl flaps open. Due to postaccident fire, the landing weight could not be established.
Wreckage and Impact Information
Examination of the accident site revealed that the departure end of runway 16 was about 0.5 miles from the first identified point of contact, a 50-ft-tall tree. A portion of wing skin was found in the tree, and the left aileron was found nearby. The main wreckage came to rest about 500 ft downslope in a vineyard. The left-wing tip tank was found 150 ft west. Recorded video showed no evidence of a pre-existing mechanical malfunction. Flight control continuity was established from the tail to the cockpit and right wing, but not to the left wing due to impact and fire damage. The three-bladed propeller exhibited s-bending, gouging, and chordwise scratching; one blade tip was missing. The crankshaft rotated manually with compression in all cylinders.
Additional Information
The FAA's Airplane Flying Handbook describes porpoising as a series of motions imitating jumps and dives, often caused by improper airplane attitude at touchdown, inattention, or improper airspeed control. When a porpoise is severe, the recommended procedure is to execute a go-around immediately.
Tests and Research
A GoPro HERO video recording device installed on the headliner captured the entire flight from about 0557 until impact, totaling about 2 hours 49 minutes. The throw-over control column was positioned for the left-seat pilot (LSP) during most of the flight and for the right-seat pilot (RSP) during descent, approach, landing, and go-around attempts. The video showed the RSP flying while the LSP lowered landing gear and flaps. During approach, the airplane entered a left bank, airspeed indicator showed 150 mph, altitude 3,000 ft msl (1,125 ft agl), and the RSP added flaps. The airplane was right of centerline; the RSP reduced manifold pressure and added nose-up trim. The airplane crossed the runway numbers with airspeed about 100 mph, then touched down sharply at 85 mph, bouncing three times consistent with a porpoised landing. The LSP called for a go-around; the RSP applied throttle, but the airplane settled back and porpoised down the runway. The airspeed decreased to 60 mph, the nose pitched up sharply, and the airplane struck trees.