ERA22LA307 · Mooney M20F

The pilot reported that he departed with the airplane’s fuel tanks full and proceeded along a route recommended by local pilots to clear the surrounding terrain. The pilot noted that the airplane’s climb performance was “less than normal” and that the airplane was “struggling” to maintain a climb rate of 500 ft per minute. As the airplane approached terrain, the pilot considered a “hard turn,” but was concerned about losing airspeed and the proximity of the terrain and chose to continue at the airplane’s best rate of climb. The airplane subsequently began to scrape across trees in a level attitude, then settled into the trees.

The airplane came to rest in heavily-wooded terrain at an elevation about 2,230 ft mean sea level (msl) southeast of the departure airport. Examination of the engine revealed that the induction air boot from the airbox to the fuel injector unit was severely degraded. No other anomalies were observed that would have precluded normal operation.

Performance information from the airplane’s pilot operating handbook indicated that the expected rate of climb given the airplane’s gross weight and the atmospheric conditions present at the time of the accident was about 1,300 ft per minute at a best rate of climb speed of 113 mph indicated airspeed. Based on this information, the airplane would travel a horizontal distance of about 2.8 statute miles (sm) to reach an altitude of 2,500 ft msl. The accident site was located about 3 sm straight-line distance from the departure airport.

The departure airport was located in a valley adjacent to a ridgeline that ran northeast/southwest. Another airport was located in the valley about 9 nautical miles south of the departure airport. Review of the sectional chart revealed that the accident site was located just north of a peak with a charted elevation of 2,289 ft msl, the highest terrain in the immediate vicinity of the departure airport.

It is possible that the condition of the fuel injector airbox boot could have affected airflow over the fuel injector impact tubes and the performance of the fuel injectors. Although this effect could not be quantified based on the available information, it may have contributed to the pilot’s perception of decreased climb performance. If the pilot had concerns about the airplane’s climb performance after takeoff, the options available included returning to the departure airport, continuing south along the valley and gaining altitude before turning on course, or diverting to the airport to the south. However, the available evidence suggests that, after takeoff, the pilot turned the airplane toward the destination airport and the area of highest terrain surrounding the departure airport, where the airplane subsequently impacted trees and rising terrain.

Verbatim NTSB analysis and probable cause from the NTSB dataset