Loss of Control in Flight · NTSB WPR13FA335
MOONEY M20C — South Lake Tahoe, CA
| Date | July 22, 2013 |
| Location | South Lake Tahoe, CA |
| Aircraft | MOONEY M20C |
| Purpose of flight | Personal |
| Conditions | Dusk · Visual Meteorological Cond |
| Phase / occurrence | Uncontrolled descent Collision with terr/obj (non-CFIT) |
| Pilot age | 66 |
| Pilot total time | 2,300 hrs · Experienced |
| Time in type | 50 hrs |
| Fatalities | 1, 1 serious |
Probable cause
NTSB findings
- Aircraft-Aircraft oper/perf/capability-Performance/control parameters-Climb rate-Capability exceeded - C
- Aircraft-Aircraft oper/perf/capability-Performance/control parameters-Airspeed-Attain/maintain not possible - C
- Personnel issues-Action/decision-Action-Incorrect action selection-Pilot - C
- Personnel issues-Action/decision-Info processing/decision-Decision making/judgment-Pilot - C
- Environmental issues-Conditions/weather/phenomena-Temp/humidity/pressure-High density altitude-Effect on operation
- Environmental issues-Physical environment-Terrain-Mountainous/hilly terrain-Contributed to outcome
What happened
The airplane was departing from a high-altitude airport. After liftoff, about midfield on runway 36, the pilot elected to turn right for a downwind departure. After the right turn, the pilot expressed concern to the passenger that the airplane could not outclimb the rapidly rising terrain. The pilot banked left to avoid a tree near the top of a ridge. The right front seat passenger heard the stall warning horn come on, and the airplane descended into the trees, coming to rest inverted on the forest floor.
Based on atmospheric conditions and an airport elevation of 6,269 feet, the calculated density altitude was 9,044 feet. According to the airplane's pilot operating handbook, for those conditions, the pilot could expect about a 330- to 490-feet-per-minute (fpm) rate of climb. The best angle-of-climb airspeed was about 82 mph. To clear the ridge ahead (180 feet above the airport elevation, not including trees), which was within 1/4 mile, the airplane would have to maintain a 981-fpm rate of climb, which was not possible given the density altitude at the time of departure.
The Federal Aviation Administration's Airport Facility Directory for the departure airport noted that the airport was surrounded on the east, south, and west by rapidly rising terrain. It further noted that for noise abatement the preferred departure runway was 36 and advised pilots to continue straight out for 1 mile before making turns.
A postaccident examination of the airframe and engine revealed no evidence of mechanical malfunctions or failures that would have precluded normal operation.