On October 28, 1995, at 1445 hours Pacific daylight time, a Piper PA-28-150, N5870W, collided with trees, power lines, and fence posts near Mecca, California, during a practice power-off forced landing. The aircraft was rented by the pilot for a private pilot practical flight test with a designated examiner. Visual meteorological conditions prevailed at the time and no flight plan was filed. The aircraft sustained substantial damage. The student pilot and the pilot examiner sustained serious injuries. The flight originated from the Thermal, California, airport on the day of the accident at 1400 as a local area instructional flight. In oral and written statements, the examiner said he gave the applicant a practice engine failure and the student set up for an approach to a field. As the aircraft neared the ground, the examiner noted the aircraft was low and told the pilot to add some power. The student did not immediately respond and the aircraft collided with trees and power lines, then the ground on a railroad right of way. The aircraft and engine were examined by Safety Board investigators after recovery from the site. No mechanical discrepancies were found in any system or component. Copies of examination reports are attached for detailed information.