What happened
The FAA’s narrative, in sentence case. The FAA writes it in capitals and removes private details.
The accident occurred on November 6, 2020 at approximately 1225. Aircraft is an experimental homebuilt RV-12, registration as N975G. Aircraft took off from runway 23 the engine failed at approximately 450' AGL. Pilot executed a steep turn and returned to runway 05. Landing was fast and rough, there was a 18-23 knot tailwind, aircraft porpoise? D on landing and may have damaged the nose gear at this point, evidenced by skid marks. The aircraft continued along braking for 450' eventually departing left of the runway and striking a taxiway marker for 23-5, a strong tailwind exacerbated the situation. The PIC is a private instrument rated pilot. The passenger wasprivacy data omitted.
Aircraft total time is 302.1, engine total time is 349.9. The aircraft engine is seized, it had fuel and oil at the time of the accident. Engine analyzer data showed fuel and oil pressure up to the point the engine stopped. All other parameters were normal. The nose gear snapped off, both main gear are bent aft and splayed. The firewall was deformed on the lower half. Both wing spars at the center bulkhead assembly had a forward bow to them. The horizontal section of the center bulkhead assembly where the MLG attaches sheared the attachment rivets and had a 45 degree curl to it increasing incident to aircraft left. The right wing tip was bent up approximately 1 inch with associated skin distortion. The right wing leading edge had impact damage from a runway marker sign. Damage was approximately 12? Wide and centered on a wing rib approximately 36" outboard of the fuselage. The impact caved in and ruptured the skin approximately 6? Affecting multiple skin panels and a wing rib. The wing spar appeared unaffected, other than previously noted. The aircraft right wing flaperon had trailing edge damage approximately 6? Long at the center of the flaperon, bent up 1?. The left wing had skin buckling on the upper aft inboard section approximately 18?X18?. Both wing undersides had underwing punctures from the MLG wheel pants and tires. The tail and empennage was undamaged.
The aircraft propeller a whirlwind GA-UL350-2B, s/n UL350-2009, blades s/n 2007 and 2008 had ground impact damage to one blade at the tip. Approximately 4? Had bent aft at a 90 degree angle. The other blade had a small quarter sized abrasion 12? From the blade root. The propeller shaft had a slight bend in it, this is suspected to have occurred as a result of the sudden stoppage and torque energy transfer to the shaft. The throttle cable barrel nut was missing, this is suspected to have occurred due to excessive force applied after engine shutdown.
An inspection of the crankshaft with the engine cases still intact revealed crankshaft separation aft of the number two connecting rod and before the number three bearing. The separation occurred at the balance weight. There is metal smearing evident on the case aft of the number two bearing. There is less significant smearing on the forward side of the number 3 bearing case. The cam shaft is intact and shows normal wear.
The engine was removed and taken to a local mechanic for disassembly. Upon splitting the cases it was evident that oil starvation was not a cause. All bearings were aligned appropriately and no evidence was present of a bearing spinning. An inspection of the crankshaft yielded a finding that the crankshaft separated due to material failure. Further analysis would be required to determine the reason for the failure. This investigation is considered closed. The NTSB has sent the crankshaft to be analyzed by a lab.
As the FAA filed it
THE ACCIDENT OCCURRED ON NOVEMBER 6, 2020 AT APPROXIMATELY 1225. AIRCRAFT IS AN EXPERIMENTAL HOMEBUILT RV-12, REGISTRATION AS N975G. AIRCRAFT TOOK OFF FROM RUNWAY 23 THE ENGINE FAILED AT APPROXIMATELY 450' AGL. PILOT EXECUTED A STEEP TURN AND RETURNED TO RUNWAY 05. LANDING WAS FAST AND ROUGH, THERE WAS A 18-23 KNOT TAILWIND, AIRCRAFT PORPOISE? D ON LANDING AND MAY HAVE DAMAGED THE NOSE GEAR AT THIS POINT, EVIDENCED BY SKID MARKS. THE AIRCRAFT CONTINUED ALONG BRAKING FOR 450' EVENTUALLY DEPARTING LEFT OF THE RUNWAY AND STRIKING A TAXIWAY MARKER FOR 23-5, A STRONG TAILWIND EXACERBATED THE SITUATION. THE PIC IS A PRIVATE INSTRUMENT RATED PILOT. THE PASSENGER WAS^PRIVACY DATA OMITTED^.
AIRCRAFT TOTAL TIME IS 302.1, ENGINE TOTAL TIME IS 349.9. THE AIRCRAFT ENGINE IS SEIZED, IT HAD FUEL AND OIL AT THE TIME OF THE ACCIDENT. ENGINE ANALYZER DATA SHOWED FUEL AND OIL PRESSURE UP TO THE POINT THE ENGINE STOPPED. ALL OTHER PARAMETERS WERE NORMAL. THE NOSE GEAR SNAPPED OFF, BOTH MAIN GEAR ARE BENT AFT AND SPLAYED. THE FIREWALL WAS DEFORMED ON THE LOWER HALF. BOTH WING SPARS AT THE CENTER BULKHEAD ASSEMBLY HAD A FORWARD BOW TO THEM. THE HORIZONTAL SECTION OF THE CENTER BULKHEAD ASSEMBLY WHERE THE MLG ATTACHES SHEARED THE ATTACHMENT RIVETS AND HAD A 45 DEGREE CURL TO IT INCREASING INCIDENT TO AIRCRAFT LEFT. THE RIGHT WING TIP WAS BENT UP APPROXIMATELY 1 INCH WITH ASSOCIATED SKIN DISTORTION. THE RIGHT WING LEADING EDGE HAD IMPACT DAMAGE FROM A RUNWAY MARKER SIGN. DAMAGE WAS APPROXIMATELY 12? WIDE AND CENTERED ON A WING RIB APPROXIMATELY 36" OUTBOARD OF THE FUSELAGE. THE IMPACT CAVED IN AND RUPTURED THE SKIN APPROXIMATELY 6? AFFECTING MULTIPLE SKIN PANELS AND A WING RIB. THE WING SPAR APPEARED UNAFFECTED, OTHER THAN PREVIOUSLY NOTED. THE AIRCRAFT RIGHT WING FLAPERON HAD TRAILING EDGE DAMAGE APPROXIMATELY 6? LONG AT THE CENTER OF THE FLAPERON, BENT UP 1?. THE LEFT WING HAD SKIN BUCKLING ON THE UPPER AFT INBOARD SECTION APPROXIMATELY 18?X18?. BOTH WING UNDERSIDES HAD UNDERWING PUNCTURES FROM THE MLG WHEEL PANTS AND TIRES. THE TAIL AND EMPENNAGE WAS UNDAMAGED.
THE AIRCRAFT PROPELLER A WHIRLWIND GA-UL350-2B, S/N UL350-2009, BLADES S/N 2007 AND 2008 HAD GROUND IMPACT DAMAGE TO ONE BLADE AT THE TIP. APPROXIMATELY 4? HAD BENT AFT AT A 90 DEGREE ANGLE. THE OTHER BLADE HAD A SMALL QUARTER SIZED ABRASION 12? FROM THE BLADE ROOT. THE PROPELLER SHAFT HAD A SLIGHT BEND IN IT, THIS IS SUSPECTED TO HAVE OCCURRED AS A RESULT OF THE SUDDEN STOPPAGE AND TORQUE ENERGY TRANSFER TO THE SHAFT. THE THROTTLE CABLE BARREL NUT WAS MISSING, THIS IS SUSPECTED TO HAVE OCCURRED DUE TO EXCESSIVE FORCE APPLIED AFTER ENGINE SHUTDOWN.
AN INSPECTION OF THE CRANKSHAFT WITH THE ENGINE CASES STILL INTACT REVEALED CRANKSHAFT SEPARATION AFT OF THE NUMBER TWO CONNECTING ROD AND BEFORE THE NUMBER THREE BEARING. THE SEPARATION OCCURRED AT THE BALANCE WEIGHT. THERE IS METAL SMEARING EVIDENT ON THE CASE AFT OF THE NUMBER TWO BEARING. THERE IS LESS SIGNIFICANT SMEARING ON THE FORWARD SIDE OF THE NUMBER 3 BEARING CASE. THE CAM SHAFT IS INTACT AND SHOWS NORMAL WEAR.
THE ENGINE WAS REMOVED AND TAKEN TO A LOCAL MECHANIC FOR DISASSEMBLY. UPON SPLITTING THE CASES IT WAS EVIDENT THAT OIL STARVATION WAS NOT A CAUSE. ALL BEARINGS WERE ALIGNED APPROPRIATELY AND NO EVIDENCE WAS PRESENT OF A BEARING SPINNING. AN INSPECTION OF THE CRANKSHAFT YIELDED A FINDING THAT THE CRANKSHAFT SEPARATED DUE TO MATERIAL FAILURE. FURTHER ANALYSIS WOULD BE REQUIRED TO DETERMINE THE REASON FOR THE FAILURE. THIS INVESTIGATION IS CONSIDERED CLOSED. THE NTSB HAS SENT THE CRANKSHAFT TO BE ANALYZED BY A LAB.
NTSB investigation
The NTSB’s investigation of this event, with its probable cause and findings. Matched to this report by N-number and date.