On August 14, 2019, about 0725 mountain standard time, an Extra Flugzeugbau EA 300L airplane, N19AM, sustained substantial damage when it was involved in an accident near Mesa, Arizona. The flight instructor and pilot receiving instruction were not injured. The airplane was operated by Aviation Performance Solutions, LLC, as a Title 14 Code of Federal Regulations Part 91 instructional flight. The flight instructor reported that a loss of engine power occurred at an altitude of 6,700 ft above ground level just after he demonstrated a rolling maneuver as part of the Upset Prevention and Recovery Training profile. Immediately following the loss of power, the flight instructor switched the fuel selector valve from the WING position (wing fuel tanks) to the ACRO/CENTER (acrobatic) fuel tank position, the gauge for which was reading just below full, and turned the airplane toward Phoenix Mesa Gateway Airport (KIWA). The flight instructor reported that based on cockpit indications, the engine was still developing partial power and he declared an emergency with KIWA tower. Approximately 4 minutes after the partial loss of engine power, and about 1 minute before touchdown, a further reduction in engine performance occurred, and the flight instructor noted a decrease in airspeed and increased descent rate. The flight instructor informed the tower of the situation. He confirmed that the emergency fuel boost pump was turned on. He subsequently made an off-airport landing, and the airplane impacted terrain in a nose-low attitude. The onsite wreckage examination was conducted by inspectors from the Federal Aviation Administration (FAA). The inspectors reported, in part, that the airplane landed on rough, uneven desert terrain overlaid with heavy brush like vegetation. The main wing assembly sustained impact damage; however, the wing fuel tanks were intact and there was no evidence of fuel leakage. The airplane’s fuel system consisted of two separate and independent fuel sources that included interconnected wing tanks for normal operations and an acrobatic/center fuel tank in the fuselage. The wing fuel tank filler caps were secure and in place. The acro/center fuel tank filler cap was secure in place, and there was no evidence of fuel leakage from the center tank assembly. The acro/center fuel tank contained approximately 13 gallons of avgas. The left-wing tank contained trace amounts of avgas and the right-wing tank contained approximately 6 gallons of avgas. The airplane was recovered to a storage facility and on November 21, 2019, the airframe and engine were examined by representatives from the National Transportation Safety Board, FAA and Lycoming Engines. The examination showed nominal damage to the engine from the impact sequence, and it was determined that a functional engine test run could be accomplished. An external fuel source was mounted to the engine to facilitate the test run. Multiple attempts to start the engine to a sustained idle power setting were unsuccessful. The airplane was equipped with a mechanical engine-driven fuel pump for normal operations, and an electrically driven fuel boost pump used, in part, for emergencies and inflight restarts following an engine failure. It was determined that the electric boost pump was inoperative and not delivering rated fuel flow. The electric boost pump was removed and replaced with a segregate boost pump. The engine started and developed continuous power at varied throttle positions between idle to full power. Once started, the electric boost pump was switched to the OFF position and the engine continued to run at varied throttle positions solely with the mechanical fuel pump. No further anomalies were noted. Following the engine examination, the electric boost pump was examined by representatives from the manufacturer and FAA. The examination revealed that the boost pump was originally manufactured by Weldon Pump of Cleveland, Ohio, and subsequently overhauled by Aeromotors, LLC, an FAA repair station. The original manufacture date could not be determined; however, records showed that the boost pump was overhauled by Aeromotors on August 8, 2018. The records showed that the electric boost pump was replaced on July 15, 2019, about 27 flight hours prior to the accident flight. Disassembly and examination of the boost pump revealed that the blade/vane retaining ring had failed, rendering the pump inoperative. The airplane flight manual states that aerobatic maneuvers must be accomplished with the fuel selector in the ACRO/CENTER (acrobatic) fuel tank position and prohibits aerobatic maneuvers with the wing fuel tanks selected.