Accident Overview
A pilot reported that while flying from Van Nuys to Mammoth Yosemite Airport (MMH) via the Friant VOR radial 023, he inadvertently entered a canyon and later realized it was the wrong one. The canyon was closed and above his altitude. The pilot experienced moderate turbulence from the time he entered the canyon until the accident.
Pilot Actions
The pilot began a full-power climb at 75 knots in an attempt to clear the ridgeline at the end of the canyon. When he realized he would not clear the terrain, he executed a steep left turn. During the turn, the stall warning activated, prompting the pilot to lower the nose and shallow the bank angle. The airplane struck trees on the top of the canyon edge, tearing off the left wing, and then struck the ground in a level attitude.
Engine and Instruments
The pilot stated that the engine was working properly and all gauges were in the green throughout the flight.
Navigational Context
According to the San Francisco sectional chart, Mammoth Pool Reservoir, located 55 nautical miles southwest of MMH on a magnetic bearing of 213 degrees, lies directly under the 023-degree radial of the Friant VOR. The pilot reported that upon seeing the reservoir, he turned east toward MMH. The magnetic course from the reservoir to MMH was 033 degrees, a northeasterly direction. A canyon leads northeast from the reservoir along the Friant 023-degree radial (also designated Victor 230). This canyon terminates at Mammoth Lakes, 11 miles due west of MMH. The pilot noted that had he followed Victor 230 until reaching Mammoth Pool and then turned to an easterly heading, he would have been proceeding directly to the airport.