BEECH C23 — Greer, SC

What happened

The pilot and mechanic were performing a postmaintenance test flight following an annual inspection of the airplane. A witness reported that the airplane took off from a private airstrip and, as the airplane passed his house, he heard a slight reduction in engine speed followed by a slight increase. The engine did not sputter or backfire. The airplane then turned toward the northwest and reached an altitude of about 500 ft above the ground. The witness observed that the left wing dipped twice then leveled off, and the airplane descended as it turned to a westerly heading. The airplane descended from his view behind a tree line, then he heard it impact the ground. The witness’s statement was generally consistent with a video that captured the accident sequence; however, the video also showed that the airplane developed a sink rate with the nose slightly up, then the nose dropped shortly before ground impact.

Postaccident examination of the wreckage revealed no evidence of a preexisting mechanical malfunction or anomaly that would have precluded normal operation. Although damage to the propeller was indicative of rotation at impact, the signatures indicated that the engine may have been running at reduced power. The temperature and dew point near the accident site were conducive to serious carburetor icing at glide (idle) power. Although it is not known how long the airplane was operated on the ground before takeoff, ground operations, such as taxi, are typically performed at low engine power settings. Additionally, it is not known if or for how long the pilot may have used carburetor heat before taking off. Given the weather conditions at the time of the accident and the lack of any mechanical issues found during the postaccident examination, it is likely that carburetor icing formed, resulting in a loss of engine power during the initial climb after takeoff. It is also possible that, while diagnosing the loss of engine power, the pilot allowed the airspeed to decay, resulting in an aerodynamic stall.

An editorial "what led to it / how to avoid it" analysis for this accident is generated separately and will appear here.