ERA22LA282

After touchdown on the runway, the airplane’s left main landing gear collapsed. The airplane skidded to the left, departed the runway surface, and struck a taxiway sign. The left wing was substantially damaged. Postaccident examination revealed that the left main landing gear torque tube had fractured, which resulted in the gear collapse. Further examination of the torque tube revealed that it failed from fatigue cracks that originated in multiple locations. A service bulletin issued by the airplane’s manufacturer required replacement of the torque tube at 4,000 hours time in service to prevent fatigue failure of the torque tube; however, the airplane had accrued about 5,000 hours total time, and the tube was original to the airplane. While compliance with the service bulletin was not mandatory, replacement of torque tube would have likely prevented the accident.

On June 18, 2022, about 1730 eastern daylight time, a Cessna 414, N414HF, was substantially damaged when it was involved in an accident near Jasper, Georgia. The commercial pilot was not injured. The airplane was operated as a Title 14 Code of Federal Regulations (CFR) Part 91 personal flight. The pilot reported that after touchdown on runway 34 the left main landing gear collapsed. The airplane skidded to the left, departed the runway surface, and struck a taxiway sign. The pilot also reported that he had “3 green” indications before touchdown, and the landing was “smooth and straight.” An inspector with the Federal Aviation Administration (FAA) responded to the accident site and examined the wreckage. The inspector reported that the left wing sustained substantial damage to the lower structure. The landing gear was collapsed, and the left main landing gear torque tube was fractured. After recovery of the wreckage to the ramp, maintenance personal removed the fractured torque tube, and it was forwarded to the National Transportation Safety Board Materials Laboratory for further examination. The examination revealed the presence of multiple fatigue cracks near the weld between the boss arm and the tube body. The opposite-facing fatigue cracks propagated inward from the outer and inner surfaces, consistent with reverse bending at this location. The cracks initiated from multiple crack initiation sites. Cessna Multi-engine Service Bulletin (SB) MEB09-2, dated May 11, 2009, addressed the issue of main landing gear torque tube failure. The service bulletin stated that noncompliance could result in fatigue failure of the torque tube. The SB required replacement of the tube at 4,000 hours of time in service. According to the owner, the airplane total time was 5,000 hours, and the torque tube was original to the airplane. The service bulletin was not included in an FAA Airworthiness Directive. An FAA fact sheet titled “Service Bulletins and the Aircraft Owner,” stated in part: “Are Service Bulletins Mandatory? The short answer is – it depends. If you are operating your aircraft under 14 CFR part 91, a service bulletin is advisory, and compliance is not mandatory unless it is included in an Airworthiness Directive. Keep in mind that even when a service bulletin is not mandatory, you should always pay attention to it as a means to ensure your safety….”