As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AIRCRAFT SUFFERED ENGINE POWER LOSS ON TAKEOFF ROLL. PILOT ABORTED TAKEOFF AND STOPPED TAKEOFF ROLL ON RUNWAY. INSPECTION REVEALED ALTERNATE AIR VALVE HAD COME LOOSE. NUT AND COTTER PIN WERE MISSING. VALVE ROLLED DOWN INSIDE INDUCTION AIR DUCT AND BLOCKED OFF AIR FLOW TO FUEL SERVO.