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On August 22, 2008, at 1847 eastern daylight time, a Bell 206A, N67AR, was destroyed when it impacted terrain during a forced landing near Barnesville, Pennsylvania. The certificated commercial pilot and passenger were seriously injured. Visual meteorological conditions prevailed, and no flight plan was filed for the local personal flight, which departed from Hazleton Municipal Airport (HZL), Hazleton, Pennsylvania. The flight was conducted under the provisions of 14 Code of Federal Regulations Part 91.
According to witnesses, the helicopter was scheduled to over-fly a driving range at a golf course, then drop golf balls from the helicopter onto the driving range for a charity event. One of the witnesses was also the fire chief of a nearby fire department.
During an interview with a Federal Aviation Administration (FAA) inspector, the chief stated that he observed the helicopter from the tee area of the driving range. The helicopter initially flew over the golf course once, then returned to the driving range area to perform the ball drop about 100 yards downrange of the tee area.
The helicopter flew along a tree line on the east side of the driving range, then performed a 180-degree turn to align with the driving range (oriented roughly 035 degrees). At that time, the helicopter was at a height where its main rotor was below the tops of the tops of the trees, and the helicopter was traveling slowly uphill towards the tee area. The chief noted that the right door of the helicopter was removed, and that there was a passenger in the right aft seat. The flight path of the helicopter was "slightly erratic," with slight roll and fore/aft pitch oscillations. The helicopter then began to "spin" to the right, while climbing, and continuing forward towards the parking lot and clubhouse. The helicopter continued away from the driving range area towards the 8th hole of the golf course before it impacted the ground facing 180 degrees from its original flight path.
The chief then proceeded to the crash site and attempted to assist the occupants. While there he noted that fuel was leaking from the helicopter, and that the engine continued to run for a brief period after the accident.
When asked about the weather on the day of the accident, the chief stated that it was a clear warm day. When asked specifically about the wind conditions, the chief stated that it was "just like today." The FAA inspector then noted that from where they were standing, at the far end of the driving range, the wind was blowing toward the tee area of the range, which was located up an approximate 5-degree slope. He further noted that the U.S. and state flags located at the top of the hill were shifting between the uphill breeze, and a breeze coming from the right side of the driving range (when looking at the tee).
The inspector discerned that based on the helicopter's described flight path, and the winds he observed, the helicopter initially approached with a headwind, which then became a tailwind as it flew uphill, with the wind shifting from a direct tailwind to a right quartering tailwind.
Another witness, who was walking from the parking lot to an area north of the driving range, saw the helicopter "spinning like a top" to the right, before he lost sight of it.
The pilot, age 79, held a commercial pilot certificate with a rating for rotorcraft-helicopter and a private pilot certificate with ratings for airplane single and multiengine land. The pilot's most recent FAA second class medical certificate was issued on October 4, 2004. On that date the pilot reported 12,300 total hours of flight experience.
Review of a single pilot logbook revealed numerous entries for flights in the accident helicopter between April 2, 2000 and September 8, 2000, when a flight review sign-off entry was made. The next two logbook entries were flight review sign-offs made on September 5, 2003 and August 18, 2004, both performed in the accident helicopter. Several more entries logged flights for a brief period in 2006, culminating with the final entry, another flight review in the accident helicopter on July 3, 2006. No further logbook entries or other logbooks were located.
Despite numerous written and telephonic requests, the pilot refused to provide any information about his pilot history or the accident flight.
According to records maintained by the FAA, the accident helicopter was manufactured in 1970. A review of the helicopter's maintenance logs was performed by an FAA inspector. During the review the inspector noted several discrepancies. Some of the items noted included that the helicopter's last annual inspection was performed prior to 2006, an emergency locator transmitter inspection (ELT) due in 2006 and ELT battery replacement due in 2007.
The weather reported at Schuylkill County Airport (ZER), Pottsville, Pennsylvania, located about 15 nautical miles southwest of the accident, at 1845, included winds from 130 degrees at 5 knots, 10 statute miles visibility, temperature 24 degrees C, dewpoint 10 degrees C, and an altimeter setting of 30.37 inches of mercury.
WRECKAGE AND IMPACT INFORMATION
The wreckage was examined at the scene on August 24, 2008 by a FAA inspector and a representative of Bell Helicopter.
The fuselage of the helicopter was oriented about 310 degrees magnetic, and exhibited downward crush damage. Ground scars and airframe damage was consistent with a relatively tail low attitude and no forward airspeed at impact. All pieces of the helicopter were located within about 100 feet of where the fuselage came to rest. The tailboom exhibited evidence consistent with at least two main rotor strikes aft of the horizontal stabilizer, and the vertical fin assembly exhibited damage consistent with ground contact. The helicopter's high-skid landing gear skid tubes were each separated from their mounting locations on the forward and aft crosstubes, and were located near the wreckage on their respective sides (with the exception of the aft end of the left skid, which was rotated around forward of the helicopter).
The pilot side cyclic stick was moved by hand laterally and longitudinally, with corresponding movement observed at both the cyclic servos and the swashplate inner ring. The control tube between the right swashplate inner ring ear and the connecting bellcrank was fractured consistent with overload. Lateral left and right movement of the cyclic control stick produced limited movement of the servos. The collective pitch control was found in the up position. Slight movement of the collective pitch control up and down by hand produced corresponding movement at the collective servo. Both main rotor pitch change links were fractured consistent with overload near the centers of each link.
The control tube from the pilot tail rotor pedals to the center console was bent about 8.5 inches from the center of the blade bolt hole, consistent with contact with the center console hole at impact. The control tube could not be moved by hand due to impact damage to the bottom of the fuselage. The tail rotor control tube in the vertical tunnel was bent near the bottom of the tube where damage to the tunnel structure had occurred. The long tail rotor control tube in the tailboom was fractured from the main rotor blade strikes aft of the horizontal stabilizer. An approximate 12-inch piece of control tube was found to the right forward of the helicopter, and exhibited flattened overload fractures on either end.
The main transmission rotated freely when the main rotor blades were rotated in the drive direction. No metallic debris was observed on the long chip detector on the bottom right side of the transmission. The main driveshaft was disconnected at both the transmission and engine ends. Both the forward and aft greased outer couplings were fractured axially consistent with a misalignment during ground contact. The freewheeling unit rotated freely in the driven (clockwise) direction, but would not rotate in the counterclockwise direction.
Three fractures were observed in the tail rotor drive system. The first fracture was of the steel tail rotor driveshaft. It was fractured in a manner consistent with overload and contact with an engine combustor drain fitting. The last shaft within the main fuselage (number 3 shaft), exhibited a torsional overload fracture with a directional twist consistent with a stoppage from the rear while under power. The tailboom contained a single, non-segmented-type shaft, which was exhibited s-bending and exhibited rotational contact signatures consistent with contact to the tail rotor driveshaft cover. Additionally, the driveshaft was fractured where it had been struck by the main rotor. The portion of the shaft aft of the fractured sections was rotated by hand, and movement was observed through the tail rotor gearbox.
The main rotor hub and blades remained attached to the mast. The main rotor was rotated freely clockwise by hand, in the direction of normal travel, and corresponding rotational movement was observed at the main driveshaft input flange on the transmission. Several main rotor blade ground strikes were observed just aft of the fractured tailboom. One main rotor blade exhibited a chordwise fracture near the tip. An approximate 2-foot section of the blade was found near the helicopter with dirt near the tip and blue paint, consistent in color with the tailboom, on the outboard leading edge surfaces. The other main rotor blade was bent down at the end of the inboard doublers. Blue paint was also observed on its outboard leading edge surfaces. Minor damage and dirt were also observed at the blade tip. Bending damage to the main rotor blades was consistent with a low rotor rpm condition at impact. Both main rotor grips exhibited free pitch change movement and the hub assembly teetered freely.
One tail rotor blade exhibited a fracture, consistent with overload, about 3 inches from the outboard blade bolt hole. The fractured section of blade was found about 100 feet aft of the wreckage near a tree. Dirt was observed near the tip of the blade and blue paint was located on the leading edge. The other tail rotor blade exhibited two chordwise bends away from the tailboom. The blade leading edge exhibited tip damage and evidence of blue paint transfer. The tail rotor hub and pitch change mechanism was free to move.
No evidence of any pre-impact mechanical failures or malfunction was noted during the examination.
The FAA issued Advisory Circular (AC) 90-95, Unanticipated Right Yaw in Helicopters, in February 1995. The AC stated that the loss of tail rotor effectiveness (LTE) was a critical, low-speed aerodynamic flight characteristic which could result in an uncommanded rapid yaw rate which does not subside of its own accord and, if not corrected, could result in the loss of aircraft control. It also stated, "LTE is not related to a maintenance malfunction and may occur in varying degrees in all single main rotor helicopters at airspeeds less than 30 knots."
Paragraph 6 of the AC covered conditions under which LTE may occur. It stated:
"Any maneuver which requires the pilot to operate in a high-power, low-airspeed environment with a left crosswind or tailwind creates an environment where unanticipated right yaw may occur."
Paragraph 8 of the AC stated:
"OTHER FACTORS...Low Indicated Airspeed. At airspeeds below translational lift, the tail rotor is required to produce nearly 100 percent of the directional control. If the required amount of tail rotor thrust is not available for any reason, the aircraft will yaw to the right."
Paragraph 9 of the AC stated:
"When maneuvering between hover and 30 knots: (1) Avoid tailwinds. If loss of translational lift occurs, it will result in an increased high power demand and an additional anti-torque requirement. (2) Avoid out of ground effect (OGE) hover and high power demand situations, such as low-speed downwind turns. (3) Be especially aware of wind direction and velocity when hovering in winds of about 8-12 knots (especially OGE). There are no strong indicators to the pilot of a reduction of translation lift... (6) Stay vigilant to power and wind conditions."