N6ZVBell 206-L4 · 1993

On October 13, 2008, at 1109 central daylight time, a Bell 206L-4, N6ZV, was destroyed when it collided with trees and impacted terrain near Conroe, Texas. Visual meteorological conditions prevailed at the time of the accident. The business flight was being conducted under the provisions of Title 14 Code of Federal Regulations (CFR) Part 91 without a flight plan. The commercial pilot and news photographer-passenger on board the helicopter were fatally injured. The flight originated in Houston, Texas, approximately 1040, and was en route to Magnolia, Texas.

The helicopter had flown earlier that morning. Upon its return, it was fueled to capacity with 44.0 gallons of Jet-A fuel. A report was received that there had been a shooting near Magnolia, Texas, and police were in pursuit of a suspect. The helicopter took off from Houston's Hobby Airport approximately 1040, and was en route to cover the breaking news story. Radar tracking of the helicopter through Houston Intercontinental Airport's airspace revealed the altitude varied between 500 and 700 feet above mean sea level(msl).

One witness reported seeing the helicopter flying approximately 350 feet above the ground from south to north when it nosed over and entered "a sharp 70 degree downward flight." Another witness, who was driving a truck towards Route 45, also saw the helicopter in a steep right bank. He said the helicopter nosed down steeply (approximately the 8 o'clock position) and dove towards the ground. He lost sight of the helicopter when it was 2 to 3 feet above the tree line. A third witness was in the Windsor Hills subdivision adjacent to the James State Park. He said the helicopter was flying approximately 100 to 300 feet at "normal power" when it suddenly banked sharply to the right (approximately 70 degrees), and he could see the rotor disk as it dove into the trees.

The burning wreckage was located in the W.G. Jones State Forest, near the intersection of Peoples Road and FM 1488. Both occupants were ejected and fatally injured.

The pilot, age 43, held a commercial pilot certificate, dated January 29, 2002, with airplane single and multiengine land, rotorcraft-helicopter, instrument-airplane, and instrument-helicopter ratings. He held a second class airman medical certificate, dated December 20, 2007, with no restrictions or limitations.

The pilot was hired by Helicopters, Inc., on September 1, 2003. His recurrent ground school was satisfactorily completed on February 3, 2008, and his recurrent flight training was satisfactorily completed on May 28, 2008. His most recent Part 135 check ride was accomplished on May 28, 2008. According to the company, the pilot had logged the following flight time:

Total Time: 6,105 hours

Rotorcraft: 5,805 hours

Bell 206L-4: 2,450 hours

According to his Crew Duty Report, the pilot had been off-duty for two days prior to the accident.

N6ZV, a model 206L-4 (s.n. 52046), was manufactured by the Bell Helicopter Corporation in 1998. It was equipped with an Allison 250-C30P turboshaft engine (s.n. CAE-895709), rated at 650 shaft horsepower.

According to the helicopter maintenance records, the helicopter was maintained under the provisions of Title 14 CFR Part 91.409(f). The last 100-hour inspection was performed on October 6, 2008. At that time, the airframe had accrued 7,992 total hours, and the engine had accrued 8,177 cycles and 7,978 total hours.

The helicopter's registered owner was Air Sansone, LLC, of Linden, New Jersey. It was leased to Helicopters, Inc., of Cahokia, Illinois. The latter provided helicopters and pilots to various companies, including Westwood One, which owned Metro Networks. Metro Networks then provided the helicopter and crew to Houston's KTRK-TV, an ABC affiliate.

The following weather observation was recorded at 1127 at David Wayne Hooks Airport (DWH), located 19 miles south-southwest of the accident site:

Wind, 110 degrees at 7 knots; visibility, 10 statute miles; sky condition, 1,600 feet scattered, 7,000 feet overcast; temperature, 27 degrees Celsius (C.); dew point, 22 degrees C.; altimeter, 30.12 inches of Mercury.

N6ZV, a model 206L-4 (s.n. 52046), was manufactured by the Bell Helicopter Corporation in 1998. It was equipped with an Allison 250-C30P turboshaft engine (s.n. CAE-895709), rated at 650 shaft horsepower.

According to the helicopter maintenance records, the helicopter was maintained under the provisions of Title 14 CFR Part 91.409(f). The last 100-hour inspection was performed on October 6, 2008. At that time, the airframe had accrued 7,992 total hours, and the engine had accrued 8,177 cycles and 7,978 total hours.

The helicopter's registered owner was Air Sansone, LLC, of Linden, New Jersey. It was leased to Helicopters, Inc., of Cahokia, Illinois. The latter provided helicopters and pilots to various companies, including Westwood One, which owned Metro Networks. Metro Networks then provided the helicopter and crew to Houston's KTRK-TV, an ABC affiliate.

The on-scene investigation commenced on October 14, 2008. There was a hole in the tree tops. The angle from this hole to the first point of impact was measured to be 72 degrees. At this first point of impact, a portion of the right skid was found embedded in the ground at a 25 degree angle. After hitting the ground, the helicopter traveled approximately 40 feet on a heading of 085 degrees before striking another tree with the main rotor mast. Two linear and parallel ground scars were noted between the trees and main wreckage. The helicopter came to rest on a magnetic heading of 105 degrees.

Most of the helicopter, including the cockpit and fuselage, was destroyed by impact forces and post-crash fire. Both main rotor blades bore evidence of tree strikes. One blade was broken in three pieces. The grips of the other blade remained attached to the hub, its composite blade destroyed by the fire. Its metal leading edge lay nearby. The rotor hub remained attached to the rotor mast. The clevis ends of the pitch change tubes remained attached to their respective horns. The pitch and collective control rods remained attached to their linkages, and the linkages were attached to their respective servos. Control continuity was established between the control rods and the servos. Continuity beyond the servos could not be established due to fire damage.

The main driveshaft was burned away from the transmission. When the main rotor blade was turned, rotation of the main input drive quill was observed. The freewheeling unit could not be turned by hand.

The tail boom sustained extensive fire damage. The aft portion of the driveshaft was fractured in torsional overload. Control continuity was established from the fracture aft to the tail rotor. One tail rotor blade was straight and the other blade was bent 90 degrees to the plane of rotation. Most of the horizontal stabilizer, synchronized elevator, and finlets were consumed by fire, but no evidence of a main rotor blade strike was noted. The tail rotor driveshaft sustained impact and fire damage, and a torsional fracture was noted. Tail rotor continuity was seen by moving the control tube and observing blade pitch changes.

Field examination of the engine revealed the connector nut on the pneumatic control line (Pg) from the power turbine governor to the accumulator connector rotated with some resistance by hand. All other intact air, oil, and fuel line connections were tight when checked by hand.

The helicopter was equipped with a video camera. Whenever the camera was not in use, it was kept in a stowed position and aimed towards the left rear skid of the helicopter at a 45 degree angle. KTRK-TV provided a DVD copy of the video tape, and it was sent to NTSB's Vehicle Recorder Laboratory for review.

According to the Video Specialist's Factual Report, the recording was 19 minutes, 5 seconds in duration, and contained no audio. The recording began when the helicopter was already in flight, flying along Interstate 45 in the vicinity of Griggs Road, about 4 nautical miles (nm) north-northwest of William P. Hobby Airport. From this point, the helicopter flew generally north-northwest towards downtown Houston. After passing Houston, the helicopter flew north along the west side of Interstate 45.

Beginning with the last 20 seconds of the recording, there was a "small perturbation in yaw (nose towards the left) followed by a return back to the right of equal magnitude." The perturbation was "no larger or faster" than other yaw motions seen previously during the flight. About two seconds later, the helicopter began a slow, smooth roll to the right and the ground was no longer visible in the video. It appeared that the helicopter remained in this right bank; the bank angle did not appear to increase or decrease appreciably. Just before the ground went out of view, the helicopter's left skid appeared to be parallel with the horizon and the roll rate appeared to have slowed or stopped.

An autopsy was performed on the pilot on October 14, 2008. Cause of death was attributed to "multiple blunt force injuries." The manner of death was ruled "Accident."

The FAA's Civil Aeromedical Institute (CAMI) conducted a toxicological screen of submitted specimens. According to CAMI's report, no carbon monoxide or drugs were detected. Cyanide tests were not performed. The 32 (mg/dL, mg/hg) ethanol detected in muscle was attributed to "sources other than ingestion" (putrefaction).

NMS Labs also conducted a toxicological screen. Their tests detected 12 mg/dL ethyl alcohol, or a blood alcohol concentration (BAC) of 0.012%. Tests were also positive for amlodipine and caffeine. The report noted that amlodipine (Norvase) is a calcium-channel blocker [used in] the treatment of hypertension and angina. The report also noted that the presence of amlodipine may be the "result of relaxation of the vascular smooth muscles and cardiac muscles."

The medical examiner of Montgomery County, Texas, analyzed tissue samples from the pilot's heart, which had been preserved after the original autopsy. Her report, dated February 14, 2010, stated the following: "Sections of the heart (left ventricle) show enlarged, irregular nuclei of myocytes consistent with hypertrophy. There is also autolysis. One section of a coronary artery shows moderate to moderate to severe atherosclerosis with cholesterol clefts and between 65 to 70% occlusion. Another section of a coronary artery shows eccentric moderate to moderate to severe atherosclerosis with 85 to 90% occlusion and small calcifications and cholesterol clefts. Another section of a coronary artery shows moderate atherosclerosis with between 60 to 65% occlusion to slightly greater occlusion. One section of a coronary artery shows eccentric moderate atherosclerosis with between 50 to 60% occlusion with cholesterol clefts. Two other sections of coronary arteries show mild to moderate atherosclerosis with approximately 30% occlusion."

The wreckage was transported to the facilities of Air Salvage of Dallas, Texas. On October 16, 2008, under FAA supervision, the wreckage was further examined. There was no evidence of a main rotor blade strike on the horizontal stabilizers and finlets or the tail boom.

On November 13, 2008, under the direction of NTSB, the helicopter's engine was disassembled and examined at Rolls Royce's factory in Indianapolis, Indiana. All external line connections had torque paint present. The only connection with broken torque paint was the Pg line where it connects to the PTG. No other anomalies were noted. By indexing each connector to the fitting with a straight line, the torque required to break the line and the torque required to realign the index marks were measured. A pneumatic leak check could not be performed due to the damage to the PTG and a fractured Pc line at the FCU connection. The fuel pump tested satisfactory. No other anomalies were noted.

The transmission and main driveshaft sustained impact and thermal damage as evidenced by their decoupling. Drive continuity was established by rotating the main rotor blade and observing rotation of the main input drive quill.

On November 14, 2008, under FAA supervision, the Pg line and fuel nozzle were bench checked at Rolls-Royce in Indianapolis. Using a differential and a digital pressure gauge (for more fidelity), shop air (22 in. Hg.) was introduced and several configurations were examined. No leaks were detected in the Pg line. Testing of the fuel nozzle revealed that some parameters did not meet specification (pattern at idle and high total flow at 200 and 550 psi), but none of the deviations were determined to be significant enough to substantially affect engine performance during the accident flight. The remainder of the engine examination and controls testing did not reveal any abnormalities.

On January 13, 2009, the freewheeling unit was examined at Bell Helicopter's Field Investigation Laboratory in Fort Worth, Texas, under FAA supervision. At the accident site, it was noted the freewheeling unit would not rotate when either the N2 or driveshaft flange were turned. The examination at Bell revealed overload fractures were found in the spline. A sprag also exhibited evidence that it had fractured in overload.