What happened
The FAA’s narrative, in sentence case. The FAA writes it in capitals and removes private details.
Khnz reported calm winds. A stabilized straight in approach was initiated around 1 pm. Approach speed was approximately 78 KTS with full flaps. Prior to touchdown, power was pulled back to idle and the plane touch downed parallel with the runway on the centerline. The aircraft touched down at approximately around the 500 from the end. Immediately directional control was lost with the plane pulling to the left. Right brake and rudder inputs failed to keep the plane on the runway and it rolled out onto the field around 800 feet hitting a runway light and marking sign at the taxi way. It continued pulling to the left and slowly crossed the field and crossed the parallel taxiway despite full braking and proceeded down a small irrigation ditch. The prop was still spinning as it contacted the ground. Markings on the runway displayed two parallel skid marks for the left main tire about 4 inches apart indicating possibly the left main was flat before touch down. No heavy skid marks from either tire was noted. Nose tire shimmy found indication of hard braking was being applied but neither tire-displayed sign of being locked.
As the FAA filed it
KHNZ REPORTED CALM WINDS. A STABILIZED STRAIGHT IN APPROACH WAS INITIATED AROUND 1 PM. APPROACH SPEED WAS APPROXIMATELY 78 KTS WITH FULL FLAPS. PRIOR TO TOUCHDOWN, POWER WAS PULLED BACK TO IDLE AND THE PLANE TOUCH DOWNED PARALLEL WITH THE RUNWAY ON THE CENTERLINE. THE AIRCRAFT TOUCHED DOWN AT APPROXIMATELY AROUND THE 500 FROM THE END. IMMEDIATELY DIRECTIONAL CONTROL WAS LOST WITH THE PLANE PULLING TO THE LEFT. RIGHT BRAKE AND RUDDER INPUTS FAILED TO KEEP THE PLANE ON THE RUNWAY AND IT ROLLED OUT ONTO THE FIELD AROUND 800 FEET HITTING A RUNWAY LIGHT AND MARKING SIGN AT THE TAXI WAY. IT CONTINUED PULLING TO THE LEFT AND SLOWLY CROSSED THE FIELD AND CROSSED THE PARALLEL TAXIWAY DESPITE FULL BRAKING AND PROCEEDED DOWN A SMALL IRRIGATION DITCH. THE PROP WAS STILL SPINNING AS IT CONTACTED THE GROUND. MARKINGS ON THE RUNWAY DISPLAYED TWO PARALLEL SKID MARKS FOR THE LEFT MAIN TIRE ABOUT 4 INCHES APART INDICATING POSSIBLY THE LEFT MAIN WAS FLAT BEFORE TOUCH DOWN. NO HEAVY SKID MARKS FROM EITHER TIRE WAS NOTED. NOSE TIRE SHIMMY FOUND INDICATION OF HARD BRAKING WAS BEING APPLIED BUT NEITHER TIRE-DISPLAYED SIGN OF BEING LOCKED.