Caldwell, ID, USA
N7956M
Beech 35
Shortly after takeoff, about 400 ft above ground level (agl), the engine began to run rough followed by a noticeable power loss. Smoke began to fill the cockpit, which appeared to be coming from the lower left firewall area. The engine continued to lose power and the pilot switched the fuel source to the right main fuel tank; however, there was no change, the engine lost total power, and the propeller stopped turning. The pilot made the decision to return to the runway; as the airplane neared the ground, it stalled, bounced, and then impacted the runway and the VASI/PAPI light structure. A postaccident examination of the airplane revealed the wastegate exhaust elbow separated from the wastegate and the tail pipe causing exhaust gas to melt the magneto P-leads, which resulted in a loss of engine power. The exhaust system was further examined, and the “V-band” clamp torque was verified to be at least 40-inch pounds (the appropriate amount); however, the tail pipe was not secure to the turbocharger despite the “V-band” clamp being torqued to the proper value. Visual inspection of the exhaust system components did not reveal any other anomalies, and the reason for the exhaust elbow separation could not be determined.
On November 23, 2019, at 1430 mountain standard time, a Beechcraft V-35A-TC airplane, N7956M, was substantially damaged when it was involved in an accident near Caldwell, Idaho. The pilot and passenger were not injured. The airplane was operated as a Title 14 Code of Federal Regulations Part 91 personal flight. According to the pilot, as he turned the airplane onto the crosswind leg of the traffic pattern after takeoff, about 400 ft above ground level (agl), the engine began to run rough followed by a noticeable power loss. Smoke began to fill the cockpit, which appeared to be coming from the lower left firewall area. The engine continued to lose power and the pilot switched the fuel source to the right main fuel tank; however, there was no change, the engine lost total power, and the propeller stopped turning. The pilot made the decision to return to the runway and about 150 ft agl, the passenger lowered the landing gear. As the pilot prepared for landing, he realized the airplane was not going to line up with the runway. He leveled the wings, and as the airplane neared the ground, it stalled and landed hard. The airplane bounced a few times before the right-wing tip struck the left side of the runway followed by the left wing impacting the VASI/PAPI light structure. The airplane came to rest upright in the soft dirt to the side of the runway. Federal Aviation Administration (FAA) inspectors examined the airplane after the accident and reported that the wastegate exhaust elbow separated from the wastegate and the tail pipe. Additionally, the magneto P-leads were melted. The exhaust system was further examined, and the “V-band” clamp torque was verified to be at least 40-inch pounds (the appropriate amount); however, the tail pipe was not secure to the turbocharger despite the “V-band” clamp being torqued to the proper value. Visual inspection of the exhaust system components did not reveal any other anomalies, and the reason for the exhaust elbow separation could not be determined.
The total loss of engine power due to the separation of the wastegate exhaust elbow.
Source: NTSB Aviation Accident Database
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