20130706011269A

ON 7/6/13 AT APPROXIMATELY 1110 CENTRAL TIME (1610Z) N7924S, A BELL 47 HELICOPTER PILOTED BY ^PRIVACY DATA OMITTED^ WAS INVOLVED IN AN ACCIDENT 3 MILES SW OF PLOVER WI WHILE CONDUCTING SPRAY OPERATIONS UNDER 14 CFR 137. THE AIRCRAFT IS OPERATED BY A RELATIVELY LARGE SPRAYING COMPANY; REABE SPRAYING. ^PRIVACY DATA OMITTED^ WAS THE SOLE OCCUPANT.

WEATHER CONDITIONS REPORTED AT THE STEVENS POINT AIRPORT (KSTE) APPROXIMATELY 6NM NORTH OF THE ACCIDENT SITE AT 1115 WERE TEMP 80 F, DEW POINT 60, WINDS SW AT 9 KTS, CLR AND VISIBILITY GREATER THAN 6.

AT THE TIME OF THE ACCIDENT THE AIRCRAFT HAD FUEL TANKS ½ FULL, AND 4 GALLONS OF PRODUCT IN ITS CHEMICAL TANKS ACCORDING TO THE WI DNR.

AFTER HAVING SERVICED A POTATO FIELD WITH FUNGICIDE AND INSECTICIDE, THE MISHAP AIRCRAFT WAS MANEUVERING TO ?TOUCH UP? MISSED AREAS PRIOR TO TERMINATING THE OPERATION. THE PILOT INITIATED A RIGHT HAND TURN FROM AN EASTERLY HEADING WITH THE INTENTION OF ROLLING OUT WEST. WITH ABOUT 40 KIAS HE PITCHED UP AND ROLLED INTO HIS TURN AT ?TREE TOP? LEVEL, APPROXIMATELY 75?. WHILE IN THE TURN THE PILOT REPORTED ?SLUGGISH? FLIGHT CONTROLS AND NOTICED HIS ENGINE RPM AT 2000, NORMAL WOULD BE IN THE AREA OF 3200. HE SAID HE BOTTOMED THE COLLECTIVE AND ROLLED THE POWER ALL THE WAY ON WITH THE TWIST GRIP, BUT HE REPORTED HE DIDN?T HEAR OR FEEL ANY INCREASE IN ENGINE SPEED. HE DID NOT LOOK INSIDE TO CONFIRM, AS HE WAS ALREADY INITIATING HIS FLARE. THE AIRCRAFT IMPACTED LEFT SKID FIRST, FOLLOWED BY THE TAIL SKID. THERE WERE WITNESS MARKS IN THE DIRT WITH BLACK AND RED PAINT CHIPS IN THEIR RESPECTIVE DIVOTS. THE AIRCRAFT LEFT THE GROUND FOR 10? AND HIT WITH BOTH SKIDS. THE AIRCRAFT THEN WENT NOSE LOW TO THE POINT THE MAIN ROTOR BLADES MADE CONTACT WITH THE GROUND, AND THE AIRCRAFT CAME TO REST ERECT ON ITS BELLY, THE SKIDS HAVING BEEN TORN OFF.

THE AIRCRAFT SUFFERED SUBSTANTIAL DAMAGE. THE WRECKAGE CAME TO REST 50 YARDS FROM INITIAL IMPACT, WHICH IS CONSISTENT WITH THE LOW AIRSPEED REPORTED BY THE PILOT. THE DEBRIS FIELD WAS FAIRLY SMALL, 100 YARDS IN DIAMETER. THE MAIN ROTOR BLADES SUFFERED DAMAGE FROM IMPACT WITH THE GROUND, AND WHILE DEFORMED THEY ARE INTACT. BOTH DRAG LINKS ARE INTACT, BUT THE ?LOLLYPOPS? OF THE FLAP RESTRAINT SYSTEM WERE BOTH SHEARED OFF. THE MAIN TRANSMISSION GEARBOX CASE WAS SPLIT, WITH NUMEROUS GEARS ON THE GROUND BESIDE THE AIRCRAFT. THE TAIL ROTOR DRIVE SHAFT WAS SEPARATED FROM ITS COUPLING ON THE AFT PORTION OF THE TRANSMISSION, AND IT WAS BROKEN AGAIN FURTHER AFT WITH SIGNS OF TORSION. THE TAIL BOOM IS ALSO SEVERED AND DEFORMED. WITH THE ASSISTANCE OF ONE OF THE OPERATOR?S PERSONNEL CONTINUITY OF THE FLIGHT CONTROLS WAS CONFIRMED. THERE WAS BINDING IN THE CABLE RUNNING FROM THE TWIST GRIP TO THE ENGINE, BUT IT WAS MOST LIKELY THE RESULT OF CRASH DAMAGE. THE FUEL TANKS WERE COMPROMISED, BUT THEY STILL CONTAINED ¼ TANK WHEN CHECKED VISUALLY.

THE PILOT SUSTAINED BURNS TO HIS NECK AND CHEST FROM HOT TRANSMISSION OIL, AND RECEIVED 6 STICHES FOR A LACERATION TO HIS HEAD. HE WAS TREATED AND RELEASED.

INSPECTION OF THE ENGINE WAS COMPLETED BY AN AIRWORTHINESS INSPECTOR, AND HE WAS UNABLE TO IDENTIFY ANY DEFECT. THE TWO MOST LIKELY SCENARIOS FOR THE MISHAP BOTH POINT TO PILOT ERROR. EITHER THE MISHAP PILOT FAILED TO INCREASE POWER ALONG WITH COLLECTIVE IN THE TURN RESULTING IN A DECAY IN ROTOR RPM, OR HE ALLOWED HIS AIRSPEED TO DECREASE IN THE TURN TO THE POINT HE ESTABLISHED A RATE OF DESCENT HE LACKED THE POWER TO ARREST.