ERA23LA310

The student pilot and flight instructor reported that the engine lost partial power after takeoff, when the airplane was climbing. The instructor assumed control of the airplane, attempted to restore power, and performed a forced landing. The airplane contacted trees and a powerline during the landing. Postaccident examination of the engine revealed that the exhaust valve in the No. 4 cylinder was stuck in the open position. Based on this finding, it is likely that the partial loss of engine power was the result of the No. 4 cylinder’s stuck exhaust valve.

On July 24, 2023, about 1630 eastern daylight time, a Piper PA-28-140, N98134, was substantially damaged when it was involved in an accident near New London, North Carolina. The flight instructor sustained minor injuries and the student pilot was seriously injured. The airplane was operated as a Title 14 Code of Federal Regulations Part 91 instructional flight. The instructional flight departed from Stanly County Airport (VUJ), Albemarle, North Carolina. According to the flight instructor, everything was normal and “in the green” during the preflight inspection, engine run-up and takeoff. During the subsequent climb, upon reaching 1,900 ft mean sea level, the engine rpm started to drop. The flight instructor immediately took control of the airplane and pitched for best glide speed while attempting to troubleshoot via the checklist, but was unable to regain full power. The engine power remained at 1,000 rpm while the propeller continued to rotate. The flight instructor attempted to return to VUJ; however, the airplane was descending too quickly, and he was unable to reach the airport. The instructor initiated a forced landing to a field that was bordered by trees. The airplane impacted the treetops, then struck electrical transmission wires and terrain before coming to rest on its nose partially inverted. A Federal Aviation Administration inspector examined the wreckage and confirmed there was substantial damage to the wings and fuselage. The right wing separated during impact and the fuel tanks were breached. The fuselage was crushed forward from the engine compartment into the cockpit. The airplane came to rest on its nose in an inverted attitude. The engine and propeller were partially canted upwards and aft into the cockpit instrument panel. The empennage was suspended by electrical transmission wires that were wrapped around the stabilator. Postaccident examination of the airframe and engine revealed that the engine crankcase was intact. The oil filter was opened revealing no foreign deposits or ferrous material. The oil appeared dark brown in color and all lubricated components appeared to be well lubricated. The fuel system was compromised during impact. The fuel selector was removed and tested yielding normal action through its rotation and indents. No blockages were observed in the fuel lines from the wings to the gascolator. During the engine continuity check, compression was obtained on cylinder Nos. 1, 2, and 3; no compression was obtained on No. 4. The No. 4 cylinder exhaust valve was stuck in the open position but became unstuck during manipulation. There was no thermal or impact damage noted to the left side of the engine. Additionally, the Nos. 3 and 4 spark plugs contained minor carbon build-up on the electrodes. The remainder of the spark plugs had normal coloration as compared to the Champion Aerospace AV-27 Check-A-Plug chart. The magnetos were mechanically manipulated with a drill and produced blue/purple spark at each of theposts. The 2-blade metal propeller blades showed evidence of minor chordwise scraping and one blade was bent uniformly aft mid span. The propeller remained attached to the flange and crankshaft and the propeller spinner was crushed inwards in a relatively flat pattern indicative of reduced power. No additional evidence was discovered to indicate a preexisting mechanical malfunction or failure that would have precluded normal operation. The airplane’s maintenance logs indicated that during the last annual inspection eight months before the accident, the engine passed a cylinder compression check, and all spark plugs were serviced. A week before the accident, the Nos. 1 and 3 pushrod seals were replaced, and leak tested, and a new left magneto was installed. At that time, the engine had a total operating time of 3,040 hours and the time since the last major overhaul was 847 hours.