NTSB Factual Report

HISTORY OF FLIGHT

On September 19, 1997, about 1410 eastern daylight time, a Bell 47G helicopter, N70747, registered to a private owner, operating as a Title 14 CFR Part 91, local instructional flight, impacted with a tree near Saluda, South Carolina. Visual meteorological conditions prevailed, and no flight plan was filed. The helicopter was destroyed. The commercial-rated/certified flight instructor (CFI) pilot and commercial-rated, second pilot/owner were fatally injured. The flight had originated from Saluda Airport at an unknown time.

About 1100, on the day of the accident, the second pilot/owner of the helicopter arrived at the Saluda Airport with the helicopter on a flatbed trailer. The CFI was to fly with the second pilot/owner and give him instruction so that he could obtain a helicopter rating. There were no witnesses to the preflight, takeoff, or the actual flight. Some people at the airport who knew the CFI, were aware that he was going to give the second pilot/owner instruction. They also had some knowledge that the second pilot had very little flight time in helicopters, and that his instruction would have to include all the basics of helicopter instruction including hovering and autorotations.

Two watches that were found in the wreckage were stopped at 1410. About 1520, the local fire department was notified that there was a fire located about 1 mile northeast of the airport. The helicopter was found in a heavily wooded area, consumed in fire.

The accident occurred during the hours of daylight approximately 33 degrees, 56 minutes north, and 081 degrees, 46 minutes west.

PERSONNEL INFORMATION

Information on the pilot is contained in this report on page 3, under First Pilot Information. Information on the second pilot is contained in this report on Supplement E. Personal log books for either of the two pilots were not found.

METEOROLOGICAL INFORMATION

Visual meteorological conditions prevailed at the time of the accident. Meteorological information is contained in this report on page 3, under Weather Information.

MEDICAL AND PATHOLOGICAL INFORMATION

Autopsies were performed on both pilots, on September 20, 1997, at the Newberry Hospital, Newberry, South Carolina, by Dr. Joel Sexton.

Toxicological tests were conducted at the Federal Aviation Administration, Research Laboratory, Oklahoma City, Oklahoma, and revealed, "Ethanol and drugs" were detected in specimens taken from the CFI. According to the toxicological report under the heading VOLATILES, "...Note: the ethanol [and drugs] found in this case may be the result of postmortem ethanol production." (Note: See the attached Toxicology Report). The specimens taken from the second pilot revealed, "no drugs or alcohol."

WRECKAGE INFORMATION

The helicopter impacted in a wooded area about 1 mile northeast of the Saluda Airport. The area consisted of pine trees which were about 50 to 60 feet in height. Inspection of the crash site revealed that the helicopter impacted with a 5 inch diameter pine tree at a height of about 40 feet off the ground. The helicopter appeared to have descended vertically from the point 40 feet above the ground and came to rest inverted near the tree. The ground fire that ensued destroyed the helicopter, rendering all instruments and gauges unreadable. In addition, the fire burned several acres of surrounding brush. Pieces of the helicopter including the ventral fin, both halves of the synchronized elevator, and a small piece of tubing were found on the ground about 15 feet north of the main wreckage. The nose of the helicopter came to rest on a heading of 140 degrees. There were no other parts of the helicopter found outside wreckage area. There was no evidence found to indicate that there was an in-flight fire and no other trees in the accident area, except the tree where the wreckage came to rest, displayed any damage.

Examination of the main fuselage revealed that the main cabin was destroyed. The main cabin displayed impact and fire damage. The center frame was distorted and scorched. Several tubes in the structure were fractured and displayed impact damage. The cabin and bubble were melted. The firewall was distorted and displayed impact damage. The engine mounting area displayed impact damage to several of the tubes, and the engine mounts were distorted. The tailboom was distorted from the rear forward. The synchronized elevator was fractured at midpoint. The ventral fin was found separated from the tailboom. The landing gear remained attached to the frame, but was fractured, and displayed impact and fire damage.

The flight control and fixed control systems revealed that most of the components were destroyed by impact and fire damage. Continuity was established, but due to heat and impact damage, no determination could be made on their condition prior to impact. Most of the control linkage below the cockpit floor was melted and displayed heat distress. Several of the steel control tubes aft of the firewall were located, but the aluminum bell cranks and torque tube pivot assemblies were melted. Both hydraulic servo actuators were found, and the servos were found melted. The hydraulic reservoir was found melted down flat against the firewall. Both cyclic stick assemblies were found melted at their bases.

The main rotor was found attached to the mast. The mast was bent about 10 degrees in the area of the collective sleeve and about 5 degrees below the rotor head. The swashplate was in place and moved freely about the gimbals. The scissors and swashplate drive assembly were found in place. One of the collective levers was burned away. The collective yoke in the swashplate support was still attached to the sleeve, and at the upper limits of its travel. The collective sleeve was locked in place, and would not move by hand. The aluminum tubes between the scissors levers and the rotor head were found melted. The main rotor hub assembly was found in place and scorched. Some of the linkage on the rotor head was found, however, none of the linkage was found fractured. Both of the main rotor blades had separated from the main rotor head, due to heat distress, from the fire. One of the blades exhibited leading edge and tip damage. This blade also displayed impact damage. The wood on the other blade had been consumed by the fire. The steel leading edge of this blade displayed impact damage. The steel retention straps and weights for both blades were present.

The tailrotor system displayed impact and fire damage. The number one section of the tailrotor driveshaft was fractured. The main portion of the driveshaft was bowed due to deformation of the tailboom. All of the hanger bearings were attached and were operable. The tailrotor output quill on the main transmission, rotated when the main rotor was turned by hand. The universal joint at the rear of the tailboom was found in place. Drive continuity was established from the universal joint through the 90 degree gearbox. The tailrotor hub and blade assembly was found attached to the 90 degree gearbox. One of the tailrotor blades was found bent 180 degrees, and displayed impact damage to the leading edge near the tip of the blade. The other blade appeared straight, and was buckled at the trailing edge near the grip. The blade was deformed aft.

The tachometer was found in the wreckage, and the face was destroyed by heat damage, rendering the numbers unreadable. However, the needles were still in place and they were split with the smaller needle (rotor), about a 45 degree split from the large needle (engine).

The main pylon including the main rotor, transmission and engine were removed from the crash site and taken to Southeast Helicopters Inc., at the Saluda Airport for further examination and disassembly.

TEST AND RESERCH

The transmission was removed from the engine and disassembled. The disassembly revealed that the shoes separated from the centrifugal clutch spider as a result of debonding from the heat of the fire. Examination of the shoes revealed that the crosshatched grooves showed no signs of abnormal wear. The clutch spider and drum were found in place. The drum was rotated by hand and revealed free rotation in one direction and locked up in the other direction, which was an indication of proper operation of the freewheeling unit. No discrepancies were found in the transmission.

The engine displayed heat distress from the fire and was partially disassembled to allow examination of internal parts. The cooling fan and support assembly were completely melted away. The front and rear crankcase covers were removed revealing the lifters and camshaft. Except for some heat distress, the lifters and camshaft did not display any discrepancies. The crankshaft was in place and all the connecting rods were attached to their respective pistons. The rocker covers were removed from all six cylinders and revealed that all the rocker arms, springs, and valves were in place and none were found broken. The spark plugs were removed and the plugs on one side of the engine all contained a gray wet material on the electrodes. It was determined that the gray material was related to water that entered the engine during the fire fighting after the crash, and corroded the plugs. The accessory section, to include both magnetos, and the oil sump were all melted. The carburetor was disassembled and revealed no fuel in bowl. The floats were found melted. The needle valve was in place and was melted. The needle valve retention pin was in place and the valve operated. No discrepancies except for heat damage was found in the carburetor. Three cylinders were removed, and because of heat damage, the removal was difficult. Except for heat damage, no discrepancies were found with the cylinders or pistons. The disassembly of the engine did not reveal any discrepancies except for heat distress caused by the fire.

ADDITIONAL INFORMATION

The airframe and engine logbooks were reported to have been onboard the helicopter and were not found. The aircraft wreckage was released to Mr. John V. Corely Jr., President, Southeast Helicopters, on September 20, 1997.

NTSB Probable Cause

in-flight collision with a tree, for undetermined reason(s).