HISTORY OF FLIGHTOn June 12, 2023, about 1029 mountain daylight time, a Cessna R182, N3138C, was substantially damaged when it was involved in an accident near McCall, Idaho. The pilot was fatally injured and the passenger was seriously injured. The airplane was operated as a Title 14 Code of Federal Regulations Part 91 personal flight. The passenger of the airplane reported that he and the accident pilot had been flying to various places around the Pacific northwest for several days. On the evening of June 11, 2023, they arrived at the McCall Municipal Airport (MYL), McCall, Idaho, and stayed overnight. Due to forecasted weather they elected to depart the following morning for a short flight to Indian Creek, Idaho. The passenger reported that the pilot conducted a preflight inspection of the airplane and pre-takeoff checks on the morning of the accident. during the taxi to the runway, the pilot commented on the slight tailwind for the departure runway, and that it may result in a slightly longer takeoff roll. As the airplane rotated for takeoff, the pilot said, “We have a power problem.” The passenger reported that the pilot stated that he wanted to return to the runway to land, but the airplane was not climbing and did not have enough altitude to fly over the trees at the departure end of the runway. Witnesses near the accident site reported that they observed the accident airplane departing to the north from MYL, and that the departure roll appeared to be “unusually long.” One witness reported that, “the engine was not developing too much power, but it sounded smooth, very low power, no coughing or sputtering….” From their vantage point, they saw the airplane's nose pitch up and begin to climb, but it did not gain enough altitude to clear the trees that were near the departure end of the runway. The airplane impacted the top of a pine tree before it descended below the tree line and out of visual range. AIRCRAFT INFORMATIONA review of the airplane’s maintenance records revealed that a single-drive dual (D-style) magneto was installed on the airplane; it had been replaced about 15 hours before the accident flight. The maintenance facility that replaced the magneto reported that the accident airplane was brought in for service due to a possible malfunctioning magneto. According to the mechanic, while he was troubleshooting the malfunction, he noted that the “P” leads were crossed. The “P” leads were switched to their proper positions and an engine run was conducted; it was confirmed that the right side of the magneto had failed. The mechanic reported that the maintenance facility was only able to perform limited to basic diagnostic testing and replacement of magnetos, and that his experience with a D-style magneto was limited. As a result, the airplane owner ordered and supplied another single-drive dual magneto to the maintenance facility. After installing the replacement magneto, several engine runs were conducted, with no further discrepancies noted. A separate mechanic conducted the quality control check of the maintenance performed. The airplane was returned to service and the pilot was advised to conduct a run-up and in-flight ignition test. If any abnormalities were present during the run-up and in-flight ignition test, the pilot was to return the airplane to the maintenance facility for further troubling shooting and diagnostics. The pilot conducted a run-up of the airplane, completed a couple of circuits in the airport traffic pattern, and then departed the area. A service instruction letter issued by the engine manufacturer provided guidance for the installation and maintenance of the single-drive dual magneto. The service instruction letter cautioned that the magneto and/or attaching hardware on the engine accessory housing can become loose or unfastened after maintenance. This condition can be caused by any, or a combination, of the following: incorrect fastening hardware installation, incorrect torquing of the fastening hardware, incorrect gasket used for the magneto installation, incorrect magneto clamps installed, and/or incorrect gap between the magneto clamp and the accessory housing. The letter noted that failure to comply with the service instruction could result in a loss of engine power. AIRPORT INFORMATIONA review of the airplane’s maintenance records revealed that a single-drive dual (D-style) magneto was installed on the airplane; it had been replaced about 15 hours before the accident flight. The maintenance facility that replaced the magneto reported that the accident airplane was brought in for service due to a possible malfunctioning magneto. According to the mechanic, while he was troubleshooting the malfunction, he noted that the “P” leads were crossed. The “P” leads were switched to their proper positions and an engine run was conducted; it was confirmed that the right side of the magneto had failed. The mechanic reported that the maintenance facility was only able to perform limited to basic diagnostic testing and replacement of magnetos, and that his experience with a D-style magneto was limited. As a result, the airplane owner ordered and supplied another single-drive dual magneto to the maintenance facility. After installing the replacement magneto, several engine runs were conducted, with no further discrepancies noted. A separate mechanic conducted the quality control check of the maintenance performed. The airplane was returned to service and the pilot was advised to conduct a run-up and in-flight ignition test. If any abnormalities were present during the run-up and in-flight ignition test, the pilot was to return the airplane to the maintenance facility for further troubling shooting and diagnostics. The pilot conducted a run-up of the airplane, completed a couple of circuits in the airport traffic pattern, and then departed the area. A service instruction letter issued by the engine manufacturer provided guidance for the installation and maintenance of the single-drive dual magneto. The service instruction letter cautioned that the magneto and/or attaching hardware on the engine accessory housing can become loose or unfastened after maintenance. This condition can be caused by any, or a combination, of the following: incorrect fastening hardware installation, incorrect torquing of the fastening hardware, incorrect gasket used for the magneto installation, incorrect magneto clamps installed, and/or incorrect gap between the magneto clamp and the accessory housing. The letter noted that failure to comply with the service instruction could result in a loss of engine power. WRECKAGE AND IMPACT INFORMATIONExamination of the accident site revealed that the airplane impacted trees about ½ mile north of the departure end of runway 34. The first identifiable point of contact (FIPC) was a 150-to 175-ft tall tree that had damaged limbs near its top. The debris path was oriented on a heading of about 335° magnetic and was about 225 ft in length from the FIPC to the main wreckage. (See Figure 1.) The debris path included the left wing and wing tip, the left aileron, and aluminum wing skin, as well as several damaged trees. The fuselage came to rest on its right side in about a 15° nose-low attitude against a tree on a heading of about 020° magnetic at an elevation of 5,033 ft mean sea level (msl). Figure 1: View of accident site Postaccident examination of the airframe verified flight control continuity from the cockpit controls to all primary flight control surfaces. Postaccident examination of the engine revealed that a single-drive dual magneto was installed. The magneto was located in its normal relative position on the mounting pad; however, it was not securely attached to the mounting pad. Both the upper and lower retaining hardware were loose, and the lower retaining hardware was also backed off ? inch from the magneto. When the magneto was manually manipulated, there was movement between the mounting pad and the magneto. Further examination of the airframe and engine did not reveal additional evidence of mechanical anomalies that would have precluded normal operation. MEDICAL AND PATHOLOGICAL INFORMATIONAn autopsy of the pilot was performed by the Ada County Coroner’s Office, Boise, Idaho. The cause of death was multiple blunt force injuries. Toxicology testing performed at the Federal Aviation Administration Forensic Sciences Laboratory found no drugs of abuse.