What happened
The FAA’s narrative, in sentence case. The FAA writes it in capitals and removes private details.
(-23) Tail rotordrive shaft failed on ground runup prior to flight while fighting forest fire near Cortez, CO. Maintenance changed all tail rotor components from the main rotor gear box aft to the tail rotor gear box. The a/c was returned to service, inspected by office of a/c services (oas), and test flown for three hours.
As the FAA filed it
(-23) TAIL ROTORDRIVE SHAFT FAILED ON GROUND RUNUP PRIOR TO FLIGHT WHILE FIGHTING FOREST FIRE NEAR CORTEZ, CO. MAINTENANCE CHANGED ALL TAIL ROTOR COMPONENTS FROM THE MAIN ROTOR GEAR BOX AFT TO THE TAIL ROTOR GEAR BOX. THE A/C WAS RETURNED TO SERVICE, INSPECTED BY OFFICE OF A/C SERVICES (OAS), AND TEST FLOWN FOR THREE HOURS.