As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
(CAN) TACH BOX FAILED WHILE ON VERY SHORT FINAL TO MOUNTAIN TOP LANDING AT 8000 FEET, AND 20 DEGREES CELSIUS. CAUSED ENGINE BLEED VALVE NOT TO CLOSE THEREBY ENGINE COMPRESSOR EXCEEDED NORMAL RED LINE. THE ENGINE WAS NOT ABLE TO MAINTAIN ROTOR RPM AND IT RAPIDLY DECAYED.