MIA08LA188 · Mooney M20C

The pilot reportedly performed a preflight inspection of the airplane using the airplane's checklist, and also performed an engine run-up before takeoff; no discrepancies were noted. The pilot applied power to take off and no discrepancies were noted. A witness reported hearing the engine running smooth but perceived it to be operating at a reduced power setting (estimated 60 percent power) during the takeoff roll. He advised the pilot on the common traffic advisory frequency to apply full power but he didn't respond. The witness saw the airplane become airborne just short of midfield, but noted that it was slow leaving the runway. Additionally, the airplane remained in ground effect for most of the remaining runway and climbed no higher than 100 feet above ground level. The pilot stated that when the flight was at that altitude, he experienced a sudden loss of engine power. He continued straight ahead past the departure end of the runway and executed a forced landing into the tops of trees. During recovery of the airplane, green colored foam and red colored lanyard material was found wedged against the engine baffling behind the propeller spinner bulkhead. No blockage of the air induction filter was noted. Following recovery of the airplane, a replacement propeller was installed and the engine was started and operated to full power as indicated by the tachometer with no discrepancies noted. Following the engine run, red colored lanyard consistent with that used as a streamer for the engine cowling ram air inlet plugs was found on top of the engine cylinders.

Verbatim NTSB analysis and probable cause from the NTSB dataset