CEN21LA306

The pilot and passenger planned to complete a combined short and soft field takeoff from a very rough grass runway, 2,375 ft in length. The pilot reported that she conducted a preflight inspection, calculated the airplane’s performance, and obtained weather information. During the takeoff roll, the engine instruments “were in the green”, but the airplane did not gain airspeed as the pilot expected. The pilot initially reported that she realized the airplane wasn’t going to clear the trees, so she attempted to abort the takeoff. However, the airplane continued past the end of the runway and impacted several small trees before coming to a stop. She added that they lifted off in ground effect but had a decrease in power and landed back on the ground past the end of the runway. An inspection of the airplane noted the right wing had separated from the fuselage and the left wing had substantial damage about mid-span. Data extracted from the airplane’s engine monitor revealed one file that corresponded with the accident flight. A review of the data noted that the engine rpm increased from about 2,260 to 2,330 for a period of 30 seconds before sudden drop in engine rpm, and just before the data ended. During an engine examination and test run, the engine started without hesitation or delay. Full throttle was applied, and the engine responded accordingly. After the test run, the corresponding data were again extracted from the engine monitor. A review of the data noted the maximum engine rpm increased during the test from about 2,200 rpm to a high of 2,323 rpm, before the throttle was reduced. No abnormalities were noted during the engine test and the engine appeared to make rated power. A review of the airplane’s performance tables indicated the takeoff roll could be 1,400 to 1,800 ft on a paved, level runway at maximum gross weight. The handbook’s data did not contain correction factors for a takeoff on a grass or rough surface runway. Based on available evidence, it’s likely that the pilot did not get performance she expected during the takeoff from the rough, grass runway and aborted the takeoff too late to stop on the remaining runway.

On July 3, 2021, about 1230 central daylight time, a Piper, PA-28-151 airplane, N181BW, was substantially damaged when it was involved in an accident near Pottsboro, Texas. The pilot and passenger were not injured. The airplane was operated as a Title 14 Code of Federal Regulations Part 91 personal flight. The pilot’s initial report after the accident indicated that she conducted a preflight inspection, calculated the [airplane’s] performance, and obtained the weather information from a nearby airport. During the takeoff roll, the engine instruments “were in the green”, but the airplane did not gain airspeed as expected. The pilot realized the airplane wasn’t going to clear the trees, so she attempted to abort the takeoff. However, the airplane continued past the end of the runway and impacted several small trees before coming to a stop. An examination by the responding Federal Aviation Administration (FAA) revealed that the runway surface was very rough, and the grass height was “okay.” The FAA noted that the right wing had separated from the fuselage and the left wing had substantial damage about mid-span, after impact with a tree. In subsequent statements, the pilot added that she planned to complete a combined short and soft field takeoff. She started the takeoff roll with full power but did not get the power she was used to. She added it was loud and bumpy on the grass runway and she “wasn’t sure if the engine was making any sounds or sputtering.” She added that they lifted off in ground effect but had a decrease in power and landed back on the ground past the end of the runway. A review of the airplane’s performance tables indicated the takeoff roll could be 1,400 to 1,800 ft on a paved, level runway at maximum gross weight. The handbook’s data did not contain correction factors for grass or rough surface runway. Additionally, the airplane was modified with an O-360 engine. Revised performance tables for the airplane with the engine modification were not available. Runway information from AirNav.com lists the runway as orientated 18-36, turf, and 2,375 feet long by 75 feet wide, at an estimated altitude of 725 feet. The airplane was equipped with a J.P. Instruments, Inc EDM-900 engine monitor. Data extracted from the unit revealed one file dated July 3, 2021, that corresponded with the accident flight for 0.17 hour. A review of the data noted that the engine rpm increased from about 2,260 to 2,330 for a period of 30 seconds before a sudden drop in engine rpm and just before the data ended. An engine examination and test run were conducted on August 23, 2021. The fuselage, minus the wings, was strapped down to a trailer. The engine cowling had been previously removed, and a visual inspection of the engine did not reveal any abnormities. A fuel canister was connected to the airplane’s fuel line near the engine’s electric fuel pump. The engine started without hesitation or delay and was then warmed up at idle rpm. The throttle was advanced, amagneto check was completed, and carburetor heat was applied; no anomalies were noted. Full throttle was then applied, and the engine responded accordingly. When the engine mixture was leaned, a slight rpm increase was observed. After the test run, the corresponding data was again extracted from the engine monitor. A review of the data noted the maximum engine rpm increased during the test from about 2,200 rpm to a high of 2,323 rpm, before the throttle was reduced. No abnormalities were noted during the engine test and the engine appeared to make rated power.