What happened
The FAA’s narrative, in sentence case. The FAA writes it in capitals and removes private details.
The pilot stated that he positioned the aircraft on runway 25 to practice take-off and landings and engaged the breaks. He brought the stick vertical and then gradually engaged the pre-rotator and brought the rotor RPM to 180. At that point he disengaged the pre-rotator, released the break, and went full throttle. The pilot stated that this is where he made the mistake by not bringing the stick all the back or full aft. As a result the aircraft accelerated but the rotor RPM started to decrease as the stick was not back. As aircraft picked up speed, the pilot started to bring the stick back, but the rotor had slowed down. The result was lift differential between the advancing and retreating blades which induced blade flap. The pilot stated that the stick became uncontrollable and the aircraft departed the left side of the runway onto the grass. The pilot cut the power to idle as left landing gear and the nose gear came off and the rotor hit the ground.
The aircraft came to a stop intact and upright, resting on chin bubble. The left gear leg bent aft slightly. There is fuselage and clamp deformation at left gear mount saddle and the wheel assembly broken off at axle. Nose gear mount structure was torn out, nose tube swung aft through belly skin, and the nose wheel is missing. Both rotor blades exhibit leading edge damage at tip and overload "s" bending. Rotor blade yokes exhibit scoring from adjacent structure. Rotor gimbal bellcrank attachment bolts (2 of 3) failed in overload. The left gimbal control rod now displaced from center of fuselage clearance hole to beyond edge indicating damage to rotor mast support structure (displaced right). The stick controls continuous and correct to rotor gimbal bellcrank. Rudder and engine controls continuous and correct. Brake system is compromised by damage to left gear.
As the FAA filed it
THE PILOT STATED THAT HE POSITIONED THE AIRCRAFT ON RUNWAY 25 TO PRACTICE TAKE-OFF AND LANDINGS AND ENGAGED THE BREAKS. HE BROUGHT THE STICK VERTICAL AND THEN GRADUALLY ENGAGED THE PRE-ROTATOR AND BROUGHT THE ROTOR RPM TO 180. AT THAT POINT HE DISENGAGED THE PRE-ROTATOR, RELEASED THE BREAK, AND WENT FULL THROTTLE. THE PILOT STATED THAT THIS IS WHERE HE MADE THE MISTAKE BY NOT BRINGING THE STICK ALL THE BACK OR FULL AFT. AS A RESULT THE AIRCRAFT ACCELERATED BUT THE ROTOR RPM STARTED TO DECREASE AS THE STICK WAS NOT BACK. AS AIRCRAFT PICKED UP SPEED, THE PILOT STARTED TO BRING THE STICK BACK, BUT THE ROTOR HAD SLOWED DOWN. THE RESULT WAS LIFT DIFFERENTIAL BETWEEN THE ADVANCING AND RETREATING BLADES WHICH INDUCED BLADE FLAP. THE PILOT STATED THAT THE STICK BECAME UNCONTROLLABLE AND THE AIRCRAFT DEPARTED THE LEFT SIDE OF THE RUNWAY ONTO THE GRASS. THE PILOT CUT THE POWER TO IDLE AS LEFT LANDING GEAR AND THE NOSE GEAR CAME OFF AND THE ROTOR HIT THE GROUND.
THE AIRCRAFT CAME TO A STOP INTACT AND UPRIGHT, RESTING ON CHIN BUBBLE. THE LEFT GEAR LEG BENT AFT SLIGHTLY. THERE IS FUSELAGE AND CLAMP DEFORMATION AT LEFT GEAR MOUNT SADDLE AND THE WHEEL ASSEMBLY BROKEN OFF AT AXLE. NOSE GEAR MOUNT STRUCTURE WAS TORN OUT, NOSE TUBE SWUNG AFT THROUGH BELLY SKIN, AND THE NOSE WHEEL IS MISSING. BOTH ROTOR BLADES EXHIBIT LEADING EDGE DAMAGE AT TIP AND OVERLOAD "S" BENDING. ROTOR BLADE YOKES EXHIBIT SCORING FROM ADJACENT STRUCTURE. ROTOR GIMBAL BELLCRANK ATTACHMENT BOLTS (2 OF 3) FAILED IN OVERLOAD. THE LEFT GIMBAL CONTROL ROD NOW DISPLACED FROM CENTER OF FUSELAGE CLEARANCE HOLE TO BEYOND EDGE INDICATING DAMAGE TO ROTOR MAST SUPPORT STRUCTURE (DISPLACED RIGHT). THE STICK CONTROLS CONTINUOUS AND CORRECT TO ROTOR GIMBAL BELLCRANK. RUDDER AND ENGINE CONTROLS CONTINUOUS AND CORRECT. BRAKE SYSTEM IS COMPROMISED BY DAMAGE TO LEFT GEAR.
NTSB investigation
The NTSB’s investigation of this event, with its probable cause and findings. Matched to this report by N-number and date.