Cessna 152 N4606L accident near Agua Dulce, California

Probable cause

The pilot's decision to continue the takeoff from the upsloping runway with full-flap deflection in high density altitude conditions, which led to a decreased climb rate and impact with terrain.

NTSB analysis

The pilot and pilot-rated passenger had rented the airplane for a cross-country flight and landed at an airport. The left-seat pilot reported that during the takeoff roll, he didn't think the airplane was accelerating fast enough, so he "pulled the power" to abort the takeoff. He reported that at that point, the pilot-rated passenger took the controls, applied full power, and continued the takeoff. The airplane was climbing slowly, but the stall warning horn sounded, and the left-seat pilot thought the airplane was going to stall. He said he took the controls and pushed the nose of the airplane down to increase the airspeed. The main landing gear struck high-voltage power lines crossing their path, and the airplane descended and impacted the terrain, which resulted in substantial damage.

The passenger said she did not remember taking the flight controls. She reported remembering the left-seat pilot "complaining" about the performance during the takeoff, reducing throttle (while still on the ground), and then reapplying power and continuing the takeoff.

The departure runway had a 1.9% uphill slope, and the terrain off the end of the runway was rising. At the time of the accident, the calculated density altitude was 5,004 ft.

An examination of the engine and airframe found no mechanical malfunctions or failures that would have precluded normal operation. However, the carburetor heat was found in the "on" position, and the flaps were extended to 30°.

It is likely that a combination of full-flap deflection and the high density altitude decreased the airplane's performance and engine horsepower output during takeoff from the upsloping runway, which adversely affected the climb rate.

Text from the NTSB. Open the NTSB docket for WPR14LA257 for the full record.