What happened
The FAA’s narrative, in sentence case. The FAA writes it in capitals and removes private details.
Upon Landing the aircraft pulled left. The pilot attempted to counter with full right rudder and braking to no avail. The aircraft exited the left side of the runway and travelled down into a ravine. The nose Landing gear struck a boulder which resulted in the aircraft flipping to an inverted position. Skid marks on the runway and in the grass indicated the left wheel was locked during the Landing roll out. There was no skid mark identified on the runway for the right wheel. Inspection of the left tire revealed a flat spot. The aircraft was placed on jacks, the left wheel rotated with light brake dragging against the brake disc. The left brake pedal was operated and found to provide firm braking. The right brake pedal was operated and found to be spongy with no braking force applied to the brake disc. The left and right brake master cylinders are equipped with stand-alone brake fluid reservoirs attached to each master cylinder. The brake fluid was found to be topped off in each reservoir. The right reservoir was found to have a (correct) vented plug while the left reservoir was found to have an (incorrect) unvented pipe plug installed. The left brake was operated with the pipe plug removed and found to operate normally without the previously observed brake dragging. The pilot/owner, who also holds a mechanic certificate, has performed all inspections, repairs and servicing on the experimental amateur built aircraft for the past two years. He stated he was unaware of the unvented pipe plug when he serviced the brake reservoirs approximately 2 weeks prior to the accident and that this was the second flight since servicing. On the morning of the accident flight, he stated that the brakes operated normally during taxi and run-up. The aircraft departed Maryland at ambient temperature of 19 degrees f. the cabin heat valve was opened fully for the flight to Georgia. The cabin heat vent discharges near the floorboard directly in front of the brake master cylinders and brake reservoirs. The pilot stated that his feet got very hot as high heat was required to maintain the comfort of the rear seat passenger.
As the FAA filed it
UPON LANDING THE AIRCRAFT PULLED LEFT. THE PILOT ATTEMPTED TO COUNTER WITH FULL RIGHT RUDDER AND BRAKING TO NO AVAIL. THE AIRCRAFT EXITED THE LEFT SIDE OF THE RUNWAY AND TRAVELLED DOWN INTO A RAVINE. THE NOSE LANDING GEAR STRUCK A BOULDER WHICH RESULTED IN THE AIRCRAFT FLIPPING TO AN INVERTED POSITION. SKID MARKS ON THE RUNWAY AND IN THE GRASS INDICATED THE LEFT WHEEL WAS LOCKED DURING THE LANDING ROLL OUT. THERE WAS NO SKID MARK IDENTIFIED ON THE RUNWAY FOR THE RIGHT WHEEL. INSPECTION OF THE LEFT TIRE REVEALED A FLAT SPOT. THE AIRCRAFT WAS PLACED ON JACKS, THE LEFT WHEEL ROTATED WITH LIGHT BRAKE DRAGGING AGAINST THE BRAKE DISC. THE LEFT BRAKE PEDAL WAS OPERATED AND FOUND TO PROVIDE FIRM BRAKING. THE RIGHT BRAKE PEDAL WAS OPERATED AND FOUND TO BE SPONGY WITH NO BRAKING FORCE APPLIED TO THE BRAKE DISC. THE LEFT AND RIGHT BRAKE MASTER CYLINDERS ARE EQUIPPED WITH STAND-ALONE BRAKE FLUID RESERVOIRS ATTACHED TO EACH MASTER CYLINDER. THE BRAKE FLUID WAS FOUND TO BE TOPPED OFF IN EACH RESERVOIR. THE RIGHT RESERVOIR WAS FOUND TO HAVE A (CORRECT) VENTED PLUG WHILE THE LEFT RESERVOIR WAS FOUND TO HAVE AN (INCORRECT) UNVENTED PIPE PLUG INSTALLED. THE LEFT BRAKE WAS OPERATED WITH THE PIPE PLUG REMOVED AND FOUND TO OPERATE NORMALLY WITHOUT THE PREVIOUSLY OBSERVED BRAKE DRAGGING. THE PILOT/OWNER, WHO ALSO HOLDS A MECHANIC CERTIFICATE, HAS PERFORMED ALL INSPECTIONS, REPAIRS AND SERVICING ON THE EXPERIMENTAL AMATEUR BUILT AIRCRAFT FOR THE PAST TWO YEARS. HE STATED HE WAS UNAWARE OF THE UNVENTED PIPE PLUG WHEN HE SERVICED THE BRAKE RESERVOIRS APPROXIMATELY 2 WEEKS PRIOR TO THE ACCIDENT AND THAT THIS WAS THE SECOND FLIGHT SINCE SERVICING. ON THE MORNING OF THE ACCIDENT FLIGHT, HE STATED THAT THE BRAKES OPERATED NORMALLY DURING TAXI AND RUN-UP. THE AIRCRAFT DEPARTED MARYLAND AT AMBIENT TEMPERATURE OF 19 DEGREES F. THE CABIN HEAT VALVE WAS OPENED FULLY FOR THE FLIGHT TO GEORGIA. THE CABIN HEAT VENT DISCHARGES NEAR THE FLOORBOARD DIRECTLY IN FRONT OF THE BRAKE MASTER CYLINDERS AND BRAKE RESERVOIRS. THE PILOT STATED THAT HIS FEET GOT VERY HOT AS HIGH HEAT WAS REQUIRED TO MAINTAIN THE COMFORT OF THE REAR SEAT PASSENGER.