On June 20, 2014, about 1430 Pacific daylight time, a Cessna 152 airplane, N4606L, sustained substantial damage during takeoff initial climb, while departing Agua Dulce Airport (L70), Agua Dulce, California. The private pilot and pilot-rated passenger were seriously injured. The airplane was registered to FLITESERV LLC., and operated by the pilot as a Title 14 Code of Federal Regulations Part 91 personal flight. Visual meteorological conditions prevailed and no flight plan was filed for the cross-country flight that originated from Long Beach Airport (KLGB), Long Beach, California, about 1245. During a telephone interview with the National Transportation Safety Board (NTSB) investigator-in-charge (IIC), the owner of the flight school reported that the pilot and passenger were both foreign private pilots of the CFR Part 141 flight school, and were working on their commercial certificates. The pilots had rented the airplane to make a cross-country flight. When queried about their destination by the owner, the pilot reported Agua Dulce Airport. The owner explained that Agua Dulce Airport did not meet the distance requirement for the advanced rating, and suggested that they overfly Agua Dulce Airport, and continue to General William J Fox Field (KWJF), Lancaster, California, which would meet the distance requirement. The owner further reported that he had interviewed the left seat pilot at the hospital and that the pilot told him that during the takeoff roll, he didn't think the airplane was accelerating fast enough, and he "pulled the power" to abort the takeoff. At that point, he said the pilot in the right seat took the controls, applied full power, and continued the takeoff. The airplane was climbing slowly, but the stall warning horn was sounding, and he (left seat pilot) thought the right seat pilot was going to stall the airplane. He said he resumed control 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 impacting the terrain. The owner reported that he was unable to speak with the right seat pilot due to her injuries. A Federal Aviation Administration (FAA) inspector reported that he had interviewed the pilot in the right seat at the hospital. He reported that her memory of the event ended at the take-off and was a bit sketchy before that. She did not remember taking the flight controls during the flight. She said she was never checked out in the Cessna 152. She did remember the left seat pilot 'complaining' about the performance during the take-off, reducing throttle (while still on the ground) and then re-applying power and continuing the take-off. She thought that the airplane was in 'clean' configuration for take-off and did not remember that the flaps were set for 'short-field'. The FAA Airport Facility Directory indicates that runway 04 has a 1.9% uphill slope. The terrain off the end of the runway is rising. The weather at the time of departure was wind variable at 4 knots, temperature 84°F, dew point 54°F, altimeter setting 29.95"hg, and calculated density altitude was 5,004 ft. During the engine and airframe examinations no mechanical anomalies were found. However, the carburetor heat was found in the "on" position and the flaps were extended to "full" 30o deflection. Several weeks after the accident the operator stopped communicating with the NTSB and the FAA. Further investigation found that the flight school was closed. The operator did not submit the NTSB Pilot/Operator Aircraft Accident/Incident Report Form 6120.1 as requested. High Density Altitude The hazards associated with high density altitude operations are outlined in an FAA Pamphlet titled DENSITY ALTITUDE (FAA-P-8740-2). The publication states, High density altitude will decrease the airplanes performance. Whether due to high altitude, high temperature, or both, reduced air density (reported in terms of density altitude) adversely affects aerodynamic performance and decreases the engine's horsepower output. Takeoff distance, power available (in normally aspirated engines), and climb rate are all adversely affected.