ERA23LA225

The pilot reported that the first leg of the cross-country flight was uneventful and that the accident occurred during takeoff following an en route stop to add fuel. He reported the takeoff roll was normal; however, during the initial climb the engine began to lose power. Video of the accident showed that the pilot attempted to continue the initial climb in three separate pitch-up attempts. Subsequently, the airplane descended, rolled to the left, and impacted terrain, which resulted in substantial damage to the fuselage and wings. It is likely that the pilot’s repeated attempts to increase the pitch of the airplane following the reported reduction in engine power likely resulted in the airplane likely exceeding its critical angle of attack and a subsequent aerodynamic stall. Postaccident examination of engine found that the Nos. 1 and 5 cylinder top spark plug ignition harnesses were loose to their respective sparkplugs. The No. 3 top spark plug ignition harness was found completely unscrewed, detached, and lying next to the spark plug on top of the cylinder shroud. There were no other anomalies discovered with the engine. Based on this information, it is likely that the reduction in engine power the pilot reported during the takeoff was due to this ignition system anomaly. The airplane had undergone maintenance and had been flown for 1.5 hours since the last inspection. The mechanic who performed that maintenance could not recall servicing any spark plugs, nor did he recall removing any ignition harnesses. Although the mechanic may not have loosened or removed the ignition harness, it is likely that he, or other maintenance personnel performing maintenance tasks at some other point, did not ensure the ignition harnesses were properly tightened before returning the airplane to service.

On May 6, 2023, about 1255 eastern daylight time, a Mooney M20K airplane, N262MK, was substantially damaged when it was involved in an accident at the Central Jersey Regional Airport (47N), Manville, New Jersey. The pilot sustained minor injuries. The airplane was operated as a Title 14 Code of Federal Regulations Part 91 personal flight. The pilot reported that he departed Brookhaven Airport (HWV), Shirley, New York, about 1120 with a final destination of Hampton Roads Executive Airport (PVG), Chesapeake, Virginia. The first segment of the cross-country flight was uneventful and the trip required a fuel stop, which was the purpose for the landing at 47N. The pilot reported that after adding about 70 gallons of 100-low lead fuel, he taxied for departure from runway 25. The pilot reported that on takeoff all engine gauges were in the green and he began the rotation after about 1,500 ft of ground roll; however, as the airplane entered the initial climb, “something just didn’t feel right.” Upon reaching about 300 ft above ground level, he stated the engine began “slowing down,” similar to the sensation of taking one’s foot off the gas pedal while driving on a highway. He ensured that the throttle, propeller, and mixture were full forward, but power was not restored. Shortly after the reduction in engine power, the left wing dropped and the airplane banked to the left and impacted an open field. Airport surveillance video captured the entire takeoff roll, initial climb, and descent towards the accident site. The video showed the airplane begin its takeoff rotation about 1,200 ft down the runway. Once the airplane entered the initial climb, its wings rocked back and forth, and three distinct pitch up control applications could be observed as the airplane’s nose pitched up from a level attitude. Subsequently, the airplane entered a left bank with a pitch up attitude and descended towards the terrain south of runway 25 before exiting out of the camera view. Examination of the airplane revealed substantial damage to the fuselage and wings. The engine remained attached to the firewall. Significant accumulation of dirt and sand was present on the bottom of the engine due to the impact with terrain, but the engine was largely free of any substantive impact damage. The propeller remained attached to its hub. It displayed leading edge gouging, blade polishing, and rearward bending. The Nos. 1 and 5 cylinder top spark plug ignition harnesses were found loose to their respective sparkplugs when touched by hand. The No. 3 top spark plug ignition harness was found completely unscrewed, detached, and lying next to the spark plug on top of the cylinder shroud. Figure 1 provides an overview of how the ignition harnesses were found when the airplane was examined at the recovery facility. Figure 1: View of the Nos. 1, 3, and 5 cylinders and ignition harnesses as found at the recovery facility. The No. 3 ignition harness was found lying next to its attachment area.The No. 1 and 5 ignition harnesses were loose to the touch. The Nos. 2, 4, and 6 cylinder ignition harnesses were all found secured and tight to their spark plugs. All top and bottom spark plugs were removed. Each were tight within the cylinders and each spark plug displayed normal combustion signatures. The crankshaft was rotated by hand. Thumb compression was observed on all the cylinders. The accessory section components rotated normally. All ignition harnesses produced spark when the crankshaft was rotated by hand. The rocker covers were removed and each valve moved normally with crankshaft rotation. There was no evidence of oil leakage on the engine or cowling. The fuel manifold valve was intact and installed to its installation area. It was removed and disassembled. The manifold contained fuel and the fuel filter screen was free of debris. The engine-driven mechanical fuel pump rotated by hand without anomalies and fuel was present in the pump. On April 16, 2023, a maintenance endorsement noted that the crankshaft seal was replaced. The intake gaskets on the Nos. 2, 4, and 6 cylinders were replaced. The propeller was removed, overhauled, and re-installed. The pilot reported that after the maintenance event, a 30-minute test flight was performed with no anomalies observed. The cross-country flight that he initiated on the day of the accident was the first flight since the maintenance test flight. Based upon the airplane’s tachometer, a total of 1.5 hours had been flown since the maintenance was performed. The mechanic who performed the maintenance in April of 2023 reported that the airplane owner (accident pilot) wanted him to troubleshoot a small amount of oil leakage coming from the engine, which the pilot had noticed accumulating on the forward windscreen during past flights. During the mechanic’s troubleshooting, he observed evidence of oil leakage on the top of the engine and near the propeller hub. The propeller was removed, overhauled, and reinstalled. While the propeller was being overhauled, he removed the old crankshaft sealant and applied new sealant on the spine of the engine. The mechanic reported that he did not recall servicing any spark plugs during this most recent maintenance in April 2023, nor did he recall removing any ignition harnesses while accomplishing work on other areas of the engine.