Incident Summary
During the initial climb at an altitude of approximately 50 to 75 feet above ground level, the flight instructor observed a decay in airspeed and repeatedly instructed the student to push forward on the controls. As the aircraft began to descend, the instructor took control and attempted to push forward, but the controls would not move forward. The airplane subsequently crossed over a power line, struck a pecan tree, and came to rest upright on its right wing.
Post-Accident Examination
Following the accident, a thorough examination of the wreckage revealed that all flight controls responded and moved the flight control surfaces through their full operating ranges. However, a battery cover was found lying free beside the elevator control push tube. The end of the push tube at the 'thru' bolt end exhibited several rub marks. Additionally, the battery cover displayed two small indentations, and the battery appeared to be new. No attachment bolts that would have been required to secure the cover to the battery were located.
Maintenance History
The aircraft had undergone an annual inspection just four days prior to the accident, and the total time flown since that inspection was five hours.