Accident Overview
On April 20, 2017, about 1845 Pacific daylight time, a Piper PA-22-150 airplane, registration N9975D, was substantially damaged in an accident near Kern Valley Airport (L05), Kernville, California. The pilot and two passengers were seriously injured. The flight was conducted under Title 14 Code of Federal Regulations Part 91 as a personal flight.
Pilot and Passenger Accounts
The pilot reported that shortly after takeoff, with full throttle applied and the airplane about 100 ft above ground level (agl) or less, he noticed decreasing engine power and the airplane was not climbing as expected. He checked the throttle and mixture control (both full forward), the fuel selector and magnetos (both set to "both"), but the airplane continued to lose altitude. Realizing the engine was not producing sufficient power to climb to or maintain 75 ft agl, he maintained a "high deck angle" to avoid stalling and turned toward an open, sandy spot for an emergency landing. During the turn, the main landing gear wheels clipped a tree, and the airplane nosed over inverted.
Conversely, the two passengers reported that the airplane departed midfield with a "very high angle of attack" that did not fluctuate even during the stall, and the pilot never lowered the airplane's nose. One passenger stated the engine sounded normal and ran at full power throughout the flight.
Video Evidence
A GoPro camera recovered from the wreckage recorded from inside the airplane, beginning at takeoff and capturing the impact about 5 minutes later. The recording indicated that the engine could be heard operating until impact, and views of the tachometer showed engine operation in the normal range.
Weather and Density Altitude
Kern Valley Airport has no weather reporting facility. The nearest automated weather observation system at Meadows Field Airport (BFL), Bakersfield, California, about 36 nautical miles southwest of Kernville, reported at 1854: temperature 22°C, dewpoint 7°C, altimeter setting 30.12 in Hg. BFL's elevation is 509 ft msl, and density altitude was calculated as 1,347 ft. The National Oceanic and Atmospheric Administration (NOAA) High-Resolution Rapid Refresh (HRRR) model sounding near L05 at 1900 PDT indicated at 2,997 ft msl (lowest reading) a density altitude of 3,996 ft msl. Kern Valley Airport's elevation is 2,614 ft.
Engine Examination
Post-accident examination found the engine still attached to the airframe via the engine mount; the carburetor had separated from the mounting flange. The two-bladed, fixed-pitch propeller remained attached, with both blades exhibiting leading edge gouging, S-bending, torsional twisting, and chordwise striation. Hand rotation of the crankshaft via the propeller produced thumb compression in proper firing order on all four cylinders. Mechanical and valve train continuity was established. Both magnetos remained attached, with timing within manufacturer limits; they produced spark at the spark plug leads when rotated. Spark plug electrodes showed coloration consistent with normal operation per the Champion Spark Plugs chart. No evidence of any preaccident mechanical malfunctions or failures that would have precluded normal operation was found.