ERA25LA238

The pilot, who was also a mechanic, purchased the twin-engine airplane nearly one year prior to the accident flight. Between the time of purchase and the accident flight he had performed some maintenance of the airplane’s engines; however, the airplane had not undergone an annual inspection at any point during the preceding 15 years, nor had the pilot obtained a special flight (ferry) permit for the accident flight. Prior to departing, the pilot performed an engine runup and noted a substantial rpm drop during the right engine magneto check. He also described that he leaned both engines’ mixture controls for takeoff due to the density altitude, and because both engines would “flood out” and not run with the mixture controls in the fully forward position. During initial climb the pilot reported the airplane seemed “sluggish,” so he advanced the mixture controls forward, after which both engines lost partial power. The pilot then decreased the airplane’s pitch attitude and landed in the grass next to the runway, which resulted in substantial damage to both wings and the fuselage. A postaccident examination of the airplane’s engines found contamination in the fuel system for the right engine. The fuel manifold valve was corroded and the fuel servo inlet screen and fuel manifold screen for the right engine were partially obstructed. Multiple spark plugs installed in the right engine exhibited corrosion, lead, and carbon fouling, and severe wear. The right engine air intake hose was found disconnected from the airbox. This condition would have likely resulted in the engine ingesting warm, unfiltered air from the cowling instead of cooler, filtered ram air. The combination of these issues likely resulted in the feeling of diminished performance the pilot reported. The examination otherwise found no evidence of any preaccident mechanical malfunctions or failures of the left engine or the airframe that would have precluded normal operation. Given the pilot’s statement that the engines would “flood out” and would not run with the mixture controls in the full forward position, it is likely that when the pilot advanced the mixture controls during initial climb the increased fuel flow resulted in the partial loss of power the pilot reported. Because this abnormal condition was known prior to the accident flight, the pilot should not have undertaken the flight without performing additional troubleshooting steps to fully understand and resolve the underlying issue(s).

On June 24, 2025, about 1230 central daylight time, a Cessna 310N, N5045Q, was substantially damaged when it was involved in an accident near Fayetteville, Tennessee. 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 he had purchased the airplane at an auction in July of 2024 in New Mexico. After purchasing the airplane, the pilot/owner, who is also a mechanic, worked on the airplane sporadically until May 25, 2025, when he flew to Okmulgee Regional Airport (OKM), Okmulgee, Oklahoma. While at OKM more maintenance was accomplished by the pilot/owner and on June 24, 2025, he flew from OKM to Fayetteville Municipal Airport (FYM), Fayetteville, Tennessee. While at FYM the pilot refueled the airplane with 40 gallons of 100LL aviation fuel which, he split between the two main fuel tanks. After refueling, the pilot started both engines and reported that during the engine run-up the right engine magneto check he observed an rpm drop of about 250 rpm. Upon departure, during initial climb, the pilot reported that the airplane “seemed very sluggish.” He advanced the mixture controls for both engines forward, towards rich, after which both engines lost partial power. He decreased the airplane’s pitch attitude and attempted to land on the remaining runway. The airplane was left of the runway and touched down in the grass, which resulted in the landing gear separating and the wings impacting the ground. The impact resulted in substantial damage to both wings and the fuselage. A postaccident examination found that both main fuel tanks had been ruptured during the impact sequence and were absent of fuel. Both auxiliary wing fuel tanks were intact and contained liquid consistent with 100LL aviation fuel. Both fuel selectors in the cockpit were found in the off position. The right engine remained attached to the airplane via the engine mount. Continuity of the crankshaft, camshaft, valvetrain, and accessory case was confirmed through multiple rotations of the crankshaft. Compression and suction were observed on all cylinders. Throttle, mixture, and propeller control continuity was confirmed from the controls in the cockpit to their respective engine control attachment points and moved throughout their full range of motion. The engine air intake hose was found disconnected from the air intake box. Both magnetos remained attached and secure to the engine; they were removed and produced a spark on all leads when rotated by hand. All top spark plugs exhibited some lead and carbon fouling and rust/corrosion but retained a gap. All top sparkplugs were observed in a worn out – severe condition when compared to the Champion Aviation Check-A-Plug chart. The bottom spark plugs were examined using a lighted borescope and exhibited a worn out – severe condition when compared to the Champion Aviation Check-A-Plug chart. The nos. 1 and 3 bottom sparkplugs were leadfouled and all other bottom sparkplugs exhibited varying levels of corrosion. The fuel servo was removed, and the fuel inlet screen was removed from the servo for examination. The fuel inlet screen was partially obstructed and corroded. The fuel manifold was removed and partially disassembled to facilitate examination. The fuel manifold valve was tight and took some force to be removed, corrosion and buildup was observed on the fuel manifold valve. The fuel inlet in the manifold exhibited a large amount of corrosion and was partially obstructed. The fuel manifold screen was partially obstructed. The fuel injector lines were tight to the fuel manifold and tight on the fuel injectors. The fuel injectors were removed and were unobstructed. The oil filter was not dated; it was removed and cut open. An examination of the oil filter pleats showed no debris. Examination of the right propeller found one blade was bent aft about 70° about 8 inches from the hub and exhibited leading edge polishing, gouges, and chordwise scratches. The other blade was bent aft about 45° about 10 inches from the hub and exhibited leading edge polishing, gouges, and chordwise scratches. The left engine remained attached to the airplane via the engine mount. Continuity of the crankshaft, camshaft, valvetrain, and accessory case was confirmed through multiple rotations. Compression and suction were observed on all cylinders. Throttle, mixture, and propeller control continuity was confirmed from the controls in the cockpit to their respective engine control attachment points and moved throughout their full range of motion. Both magnetos remained attached and secure to the engine; they were removed and produced a spark on all leads when rotated by hand. All top sparkplugs were observed in a normal condition when compared to the Champion Aviation Check-A-Plug chart. All bottom spark plugs were examined using a lighted borescope and exhibited a worn out – normal condition when compared to the Champion Aviation Check-A-Plug chart. The fuel servo was removed, and the fuel inlet screen was removed from the servo for examination. The fuel inlet screen was unobstructed. The fuel manifold was removed and partially disassembled to facilitate examination. The fuel manifold valve was removed and was clean. The fuel manifold screen was unobstructed. The fuel injector lines were tight to the fuel manifold and tight on the fuel injectors. The fuel injectors were removed and were unobstructed. The oil filter was not dated; it was removed and cut open. An examination of the oil filter pleats showed a small amount of nonferrous debris. Examination of the right propeller found one blade was bent aft about 45° about 12 inches from the hub. The blade exhibited leading edge polishing, leading edge gouging, and chordwise scratching. The other blade was secure in the hub and was bent aft about 70° about 12 inches from the hub. The blade exhibited leading edge polishing, leading edge gouging, andchordwise scratching. A review of maintenance records showed the last annual inspection for the airplane was completed on February 29, 2008, at a tachometer time of 577.4 hours. The left engine was installed on the airplane after a factory overhaul on August 12, 2006, and had accumulated 87.2 hours at the time of the accident. The right engine was installed on the airplane in 1995 after a factory overhaul and had accumulated 1,389.4 hours at the time of the accident. Two entries were made on March 28, 2025, by the pilot/owner, one stated “rmvd, replaced RH engine Fuel Flow (manifold) assy” and the other stated “Removed, rebuilt, replaced fuel manifold flow divider.” An entry dated June 21, 2025. stated “removed, cleaned & reinstalled (12ea) spark plugs on LH engine upper side.” An entry from June 22, 2025, stated “Removed, cleaned & reinstalled (24ea) spark plugs on RH engine.” The pilot was asked if he could provide a special flight (ferry) permit under Title 14 CFR Part 21.197 and he stated, “I do not have a ferry permit to forward to you.” According to FAA airworthiness records, the owner-pilot applied for an Airworthiness Certificate replacement on November 30, 2024, but there was no record of a special flight permit request for the accident airplane. When queried as to why the pilot had not taken off with the mixture controls set to full forward (rich) the pilot stated that he had adjusted the mixture during the engine run-up to achieve maximum rpm due to the density altitude at the airport. When asked if the engines would operate with the mixture controls in the full forward position, he reported that they would not and that they would “flood out.” The Continental Aerospace Technologies Standard Practice Maintenance Manual (M-0) chapter 6, section 6-3 Time Between Overhaul stated: Environmental corrosion occurs internally and externally on an engine. This naturally occurring process can affect continued airworthiness of the engine and engine mounted components or accessories. Regardless if the engine has been operated regularly or has been in storage; gaskets, seals, and synthetic and natural rubber goods deteriorate over time. Replace or overhaul the engine upon accumulating the operating hours specified in Table 6-1, or twelve (12) years after being placed in service, whichever occurs first. The Cessna 1968 Model 310N Owner’s Manual Before Takeoff Checklist stated: Magnetos – Check (150 RPM maximum drop with a maximum differential of 50 RPM).