CEN25LA021

The pilot reported that during a go-around after a bounced landing, the engine did not produce full power. The pilot chose to perform the go-around due to the bounced landing on the short, grass runway. During engine throttle application, the pilot noticed that the airplane did not attain the normal acceleration rate. The pilot verified the position of the cockpit engine controls; however, the airplane was still underperforming. Before the pilot could attempt any further actions, the airplane settled into the tree line at the end of the runway, impacted multiple trees, and came to rest inverted about 4 feet off the ground, which resulted in substantial damage to both wings, the fuselage, and the empennage. Multiple witnesses reported that the engine sounded as if it was not producing full rated power. Postaccident examination of the airframe revealed no evidence of mechanical malfunctions or failures that would have precluded normal operation. However, a review of recorded engine data showed that the engine was not producing full power during the approach, landing, and go-around. Recorded engine monitor data indicated a sharp drop in the No. 1 cylinder’s Exhaust Gas Temperature (EGT) from 1321° F to 365° F as the pilot was turning onto final approach. Over the next minute, the No. 1 cylinder’s EGT rebounded twice before again falling relative to the other cylinders’ EGTs. When the pilot applied full engine power during the go-around, the No. 1 cylinder’s EGT jumped from 532° F to 863° F for less than one second before again dropping down to 526° F. Three seconds later the No. 1 cylinder’s EGT returned to normal, in line with the other cylinders; however, full engine power was not restored until 11 seconds after the pilot commanded full engine power. This is likely the No. 1 cylinder air fuel mixture was too lean for proper combustion. At the start of the initial decent, the highest recorded cylinder EGT temperature was 1,467° F and the lowest 1,306° F. At the start of the descent from traffic pattern altitude for landing, the highest recorded cylinder EGT was 1,480° and the lowest was 1,351° F. During the go-around, the fuel flow was steady at about 10 gph until the end of the recording when the fuel flow suddenly increased to 15 gph in about one second. Additional review of the engine data revealed that during takeoff and initial climb, the maximum recorded fuel flow was 20.6 gph which is 2.4 gallons below the minimum required full engine power fuel flow of 23.0 gph. Review of the maintenance logbooks did not reveal a fuel injection system calibration during the most recent annual inspection as required by manufacturer’s maintenance manual. Due to a lack of recent calibration of the fuel injector system, it is likely that the system would not have provided the required fuel flow to the engine. On the accident flight, the pilot likely did not enrichen the mixture before starting the descent until after established in the go-around. During thego-around, the pilot likely observed that the mixture was not properly set when he noticed the degraded performance of the engine. This is consistent with the sudden increase in recorded fuel flow and engine power before end of the data and subsequent impact with trees.

On October 17, 2024, about 1432 central daylight time, a Mooney M20K airplane, N231MW, was substantially damaged when it was involved in an accident near Elizabeth, Louisiana. The pilot and passenger were uninjured. The airplane was operated as a Title 14 Code of Federal Regulations Part 91 personal flight. The pilot reported that during a go-around after a bounced landing at WC Field (LS46) in Elizabeth, Louisiana, the engine did not produce full power. The pilot chose to perform the go-around due to the bounced landing on the short, grass runway. During engine throttle application, the pilot noticed that the airplane did not attain the normal acceleration rate. The pilot verified the position of the cockpit engine controls; however, the airplane was still underperforming. Before the pilot could attempt any further actions, the airplane settled into the tree line at the departure end of the runway, impacted multiple trees, and came to rest inverted about four feet off the ground, resulting in substantial damage to both wings, the fuselage, and the empennage. Multiple witnesses reported that the engine sounded as if it was not producing full rated power. Postaccident examination of the airframe revealed no evidence of mechanical malfunctions or failures that would have precluded normal operation. The engine had continuity from the crankshaft to the accessory section and the valves operated normally when the engine was rotated by hand with the propeller. A borescope inspection of the cylinders did not reveal any abnormalities. The airplane was equipped with an Electronics International MVP-50P digital engine monitor, which was recovered and successfully downloaded by the NTSB Vehicle Records Laboratory. Review of the engine data indicated that the engine fuel flow and the No. 1 cylinder’s EGT varied considerably during the approach, landing, and go-around (see figure). Figure. Plot of engine parameters for about the final 3 minutes of the accident flight. According to the engine manufacturer, the recorded engine data shows that the No. 1 cylinder operates with the leanest fuel air mixture. As the pilot was turning onto final approach for runway 18, the engine monitor recorded a decrease in the No. 1 cylinder EGT from 1321° F to 365° F. Over the next minute, the No. 1 cylinder EGT increased twice before decreasing relative to the other cylinder EGTs. At 1432:26, when the pilot applied full engine power during the go-around, the No. 1 cylinder EGT increased from 532° F to 863° F for less than one second before decreasing back to 526° F. Three seconds later, the No. cylinder 1 EGT again began to positively correlate with the other cylinders’ EGTs. However, full engine power was not regained for about 11 seconds after the pilot applied full engine power. At 1413:24, at the start of the initial decent from cruise altitude, the highest recorded cylinder EGT temperature was 1467° F and the lowest 1306° F. At the start of the descent from traffic patternaltitude for landing, the highest recorded cylinder EGT was still about the same at 1480° and the coldest at 1351° F. During the go-around, the fuel flow was steady at about 10 gph until the end of the recording when the fuel flow suddenly increased to 15 gph in about one second. Additional review of the engine data revealed that during takeoff and initial climb, the maximum recorded fuel flow was 20.6 gph, which is 2.4 gallons below the minimum required full engine power fuel flow of 23.0 gph. Review of the maintenance logbooks did not reveal a fuel injection system calibration during the most recent annual inspection. This system calibration is required by Continental to be performed annually by 6-4.7 in Chapter 6 of the M-0 Standard Practice Maintenance Manual. According to the engine manufacture, the lack of calibration of the fuel injector system would prevent the engine from receiving the required fuel flow.