What happened
The FAA’s narrative, in sentence case. The FAA writes it in capitals and removes private details.
On 20 November, 2010 at 1953Z, privacy data omitted piloting a C-208 from cpr to rks at 12,000 feet, experienced mountain wave causing his aircraft to begin a descent. The autopilot could not maintain altitude. privacy data omitted Switched off the autopilot and placed the aircraft in a max power climb, yielding a 500 fpm rate of decent. At approximately 200 feet below his assigned altitude, he contacted salt lake center to advise them of his problem. The aircraft decended to approximately 11,000 feet before beginning a climb back to 12,000 feet. The flight continued to its destination without further incident.
As the FAA filed it
ON 20 NOVEMBER, 2010 AT 1953Z, ^PRIVACY DATA OMITTED^ PILOTING A C-208 FROM CPR TO RKS AT 12,000 FEET, EXPERIENCED MOUNTAIN WAVE CAUSING HIS AIRCRAFT TO BEGIN A DESCENT. THE AUTOPILOT COULD NOT MAINTAIN ALTITUDE. ^PRIVACY DATA OMITTED^ SWITCHED OFF THE AUTOPILOT AND PLACED THE AIRCRAFT IN A MAX POWER CLIMB, YIELDING A 500 FPM RATE OF DECENT. AT APPROXIMATELY 200 FEET BELOW HIS ASSIGNED ALTITUDE, HE CONTACTED SALT LAKE CENTER TO ADVISE THEM OF HIS PROBLEM. THE AIRCRAFT DECENDED TO APPROXIMATELY 11,000 FEET BEFORE BEGINNING A CLIMB BACK TO 12,000 FEET. THE FLIGHT CONTINUED TO ITS DESTINATION WITHOUT FURTHER INCIDENT.