20240923014779A

ON SEPTEMBER 23, 2024, ABOUT 1357 CENTRAL DAYLIGHT TIME, AN EXPERIMENTAL AVIAT AIRCRAFT INC S-1-11B AIRPLANE, ^PRIVACY DATA OMITTED^, WAS SUBSTANTIALLY DAMAGED WHEN IT IMPACTED THE CUMBERLAND RIVER NEAR THE WHIFFERDILL AIRPORT (TN77), CHAPMANSBORO, TENNESSEE. THE COMMERCIAL PILOT WAS FATALLY INJURED. THE AIRPLANE WAS OPERATED BY THE PILOT AS A PERSONAL FLIGHT CONDUCTED UNDER THE PROVISIONS OF TITLE 14 CODE OF FEDERAL REGULATIONS PART 91.

ADSB DATA SHOWS THE AIRPLANE DEPARTED TO THE SOUTHEAST FROM TN77 AIRPORT ABOUT 1345. THE FLIGHT TRACK SHOWED THAT THE AIRPLANE REMAINED ABOUT ONE MILE SOUTH OF THE AIRPORT FOR THE MAJORITY OF FLIGHT PERFORMING LOW ALTITUDE MANEUVERS BETWEEN THE SURFACE AND 1,600 FT ABOVE GROUND LEVEL. ACCORDING TO A WITNESS WHO WAS ON A KAYAK ON THE CUMBERLAND RIVER, ABOUT A HALF MILE SOUTH OF THE ACCIDENT SITE, THE AIRPLANE HAD BEEN PERFORMING A VARIETY OF AEROBATICS AT LOW ALTITUDE. HE DESCRIBED THAT THE ENGINE SOUND WOULD GO QUITE AND THEN “REV” BACK UP DURING THE MANEUVERING. HE TOOK SEVERAL CELL PHONE VIDEOS OF THE FLYING, INCLUDING A VIDEO THAT WAS ABOUT TWO MINUTES IN DURATION THAT CAPTURED THE FINAL MOMENTS OF FLIGHT. THE VIDEO SHOWED THE AIRPLANE PERFORMING A VARIETY OF AEROBATIC MANEUVERS AT LOW ALTITUDE. IN THE FINAL MOMENTS OF THE VIDEO, THE AIRPLANE DESCENDED, GAINED SPEED, AND THEN CLIMBED AND COMPLETED 4-POINT AILERON ROLL. THE AIRPLANE CONTINUED TO CLIMB AFTER THE ROLL, AND THEN MOVED OUT OF THE CAMERA VIEW. THE AIRPLANE BRIEFLY REAPPEARED INTO VIEW, WHERE THE AIRPLANE WAS OBSERVED IN A VERTICAL NOSE HIGH ATTITUDE BUT DESCENDING STRAIGHT DOWN. IN THE LAST 1-2 SECONDS OF VIDEO, THE AIRPLANE WAS OBSERVED IN AN INVERTED FLAT SPIN, ROTATING NOSE LEFT, DESCENDING NEARLY STRAIGHT DOWN TOWARDS THE RIVER. THE ENGINE NOISE WAS CONTINUOUS DURING THE FINAL MOMENTS OF VIDEO. THE AIRPLANE IMPACTED SHALLOW WATER IN THE CUMBERLAND RIVER ABOUT 100-200 FT FROM THE LAST OBSERVED ADS-B RECORDED POSITION.

THE WRECKAGE WAS FOUND INVERTED, WHICH WAS INDICATIVE OF THE AIRPLANE IMPACTING THE WATER IN A FLAT INVERTED ATTITUDE. THE AIRPLANE WAS FLOATED TO A DOCK VIA THE USE OF INFLATABLE BAGS AND BOATS. THE FUSELAGE AND ALL FLIGHT CONTROL SURFACES REMAINED INTACT, AND THE ENGINE REMAINED ATTACHED TO THE AIRFRAME. THE TOP OF FUSELAGE EXHIBITED DOWNWARD CRUSHING, AND THE BOTTOM FUSELAGE STRUCTURE WAS RELATIVELY FREE OF DAMAGE. THE CANOPY WAS CRUSHED AND WAS NOT RECOVERED. THE MAIN LANDING GEAR AND TAILWHEEL REMAINED ATTACHED TO THE FUSELAGE AND SUSTAINED LITTLE DAMAGE. FLIGHT CONTROL CONTINUITY WAS CONFIRMED FROM ALL FLIGHT CONTROL SURFACES TO THE COCKPIT. THE FLIGHT CONTROL STICK REMAINED ATTACHED TO ITS INSTALLATION AREA. THE CONTROL STICK MANIPULATED THE ELEVATOR AND AILERON PUSH PULL RODS NORMALLY. THE LEFT AND RIGHT AILERON PUSH PULL ROD ATTACHMENTS REMAINED INSTALLED TO THEIR RESPECTIVE CONTROL SURFACES AND MOVED NORMALLY. THE RUDDER CONTROL CABLES WERE CONTINUED TO THE CONTROL SURFACE FROM THE PEDALS AND MOVED THE RUDDER NORMALLY. THE TOP OF THE RUDDER AND VERTICAL STABILIZER WERE FOUND BENT OVER 90 DEGREES TO THE RIGHT, WHICH WAS CONSISTENT WITH AN INVERTED FLAT SPIN ROTATING TO THE LEFT. THE THROTTLE WAS FOUND IN A MID-POSITION. THE MIXTURE AND PROPELLER LEVERS WERE FOUND FULL FORWARD. THERE WERE SEVERAL GO-PRO CAMERA MOUNTS, HOWEVER; NO CAMERAS OR OTHER DEVICES THAT RECORDED DATA WERE LOCATED.

THE AIRPLANE WAS EQUIPPED WITH A BARRETT PERFORMANCE AIRCRAFT AEIO-540 EXPERIMENTAL ENGINE. THE ENGINE WAS NOT EQUIPPED WITH A DATA PLATE. THE ENGINE REMAINED INTACT AND WAS FREE OF MAJOR IMPACT DAMAGE. THE ENGINE WAS SUBMERGED IN THE WATER FOR ABOUT 24 HOURS AND HAD A SUBSTANTIAL AMOUNT OF SOOT, MUD DEBRIS, AND WATER RETAINED INTERNALLY. THE ENGINE EXHIBITED CRANKSHAFT AND CAMSHAFT CONTINUITY AND THUMB COMPRESSION ON ALL CYLINDERS. THE TOP AND BOTTOM SPARK PLUGS EXHIBITED NORMAL COMBUSTION SIGNATURES. THE MAGNETOS REMAINED SECURED TO THE ENGINE. THE LEFT MAGNETO EXHIBITED SPARK WHEN ROTATED BY HAND AFTER REMOVAL FROM THE ENGINE.