East Hanover Tw, PA, USA
N22MP
Bell 47G-3B-1
The private pilot was conducting an out-of-ground effect hover over his property, while the passenger took photographs. At the time, the reciprocating engine helicopter was about 200 feet agl, in an approximate 5 to 10-knot tailwind. The tail of the helicopter began to oscillate left and right, followed by a nose-down descent and impact with a building and terrain. Although the tail oscillated, the helicopter did not spin. The weight of the helicopter at the time of the accident was approximately 2,570 lbs, which was under the 2,850-lb. maximum gross weight of the helicopter. Review of the rotorcraft flight manual revealed that the helicopter was on the edge of the performance envelope, where it could hover out-of-ground-effect at 2,500 lbs., under the given conditions, but not at 2,850 lbs., under the given conditions. In addition, the performance information did not contain any data for hovering out-of-ground-effect in a tailwind, and a tailwind may have required the use of more tail rotor thrust to maintain directional control, which meant there was less power available to the main rotor for the production of lift. Examination of the wreckage did not reveal any pre-impact mechanical malfunctions.
HISTORY OF FLIGHT On April 20, 2006, at 1618 eastern daylight time, a Bell 47G-3B-1, N22MP, was destroyed when it impacted terrain while maneuvering near East Hanover Township, Pennsylvania. The certificated private pilot and passenger were fatally injured. Visual meteorological conditions prevailed for the flight that departed Sky Classics Field (7PS4), Grantville, Pennsylvania. No flight plan was filed for the local personal flight conducted under 14 CFR Part 91. According to a Muir Army Airfield (MUI), Annville, Pennsylvania, air traffic control (ATC) transcript, the accident pilot contacted the Muir ATC tower at 1613:25. At 1613:32, the accident pilot stated that he was about 900 feet msl, 3.5 miles southwest of the airfield, and would like to do some photography work. At 1613:55, the ATC controller acknowledged the request and provided a traffic advisory. The accident pilot then replied that he had the traffic in sight. At 1614:37, the ATC controller queried the accident pilot as to his altitude, and the accident pilot replied 700 feet. No further transmissions were received from the accident pilot. At 1618:21, the ATC controller observed black smoke in the vicinity of where the accident pilot stated that he was performing photography work. The helicopter initially impacted a building located on a horse farm owned by the pilot. It then struck a light pole, came to rest in a parking area on the horse farm, and a post crash fire ensued. According to a witness employed at the farm, the pilot had completed several local flights during the day, and the accident flight was his third or fourth. The pilot had recently purchased the property, and was flying over it with the intention of having the passenger take photographs. The witness stated that after approximately 15 minutes of the helicopter flying overhead, she heard engine noise decrease, and observed the helicopter descending quickly to the ground. Another witness was a helicopter pilot that lived near the accident site. About 1620, he observed the accident helicopter in an out-of-ground-effect hover, about 250 feet agl, for 5 to 10 minutes. At the time, the helicopter was hovering in a 5 to 10-knot tailwind. The witness then observed the helicopter move slowly forward and right, and begin to descend. The witness thought that the pilot was landing, and discontinued observation. The witness heard constant engine noise, followed by an engine rev for 2 to 3 seconds. He then heard, "the engine speed bogging down as under full load to around 2,000 rpm over several seconds, followed immediately by an impact sound and huge cloud of black smoke." A third witness was a heavy equipment operator, and was working about 1/4-mile west of the accident site. He observed the accident helicopter in an approximate 200-foot hover, and noticed that the tail was oscillating. The witness thought that the pilot was new, or having difficulty controlling the helicopter. The nose then suddenly dropped to the ground. The witness further stated that he heard the pilot "put in engine power and then let it off." A fourth witness lived about 1/8-mile from the accident site. He observed the helicopter in a hover, and believed that it was less than 500 feet above the ground. The helicopter then "nose dived" to the right and impacted terrain. The witness further stated that he heard constant engine noise throughout the accident sequence. The four witnesses stated that the helicopter did not spin prior to the nose-down descent or impact. The accident occurred during the hours of daylight; located approximately 40 degrees, 22.82 minutes north latitude, and 76 degrees, 36.97 minutes west longitude. PERSONNEL INFORMATION The pilot held a private pilot certificate, with ratings for airplane single engine land, airplane multi-engine land, instrument airplane, and rotorcraft-helicopter. His most recent Federal Aviation Administration (FAA) second class medical certificate was issued on September 1, 2004. According to his logbook, the pilot had accumulated a total flight experience of approximately 937 hours; of which, about 148 hours were in helicopters, with almost all of the hours in the same make and model as the accident helicopter. The pilot received his rotorcraft-helicopter rating on December 21, 2003. He flew approximately 64 hours during the 90 days preceding the accident; of which, about 24 hours were in the accident helicopter, and the remainder were in a single engine airplane. AIRCRAFT INFORMATION The helicopter was maintained under a continuous maintenance program. Its most recent 25-hour inspection was performed on October 15, 2005. The helicopter's most recent annual inspection was performed on April 28, 2005. The helicopter had accumulated approximately 25 hours of operation since the 25-hour inspection, and 52 hours of operation since the annual inspection. In addition, the helicopter was serviced on April 13, 2006, which included an oil change, aircraft greasing, engine degreasing, and compliance with an airworthiness directive regarding an oil filter inspection. METEOROLGOGICAL INFORMATION The reported weather at MUI, located about 3 miles northeast of the accident site, at 1623, was: wind from 300 degrees at 7 knots, gusting to 14 knots, varying between 250 degrees and 320 degrees; visibility 25 miles; overcast ceiling at 30,000 feet; temperature 82 degrees F; dew point 14 degrees F; altimeter 29.90 inches Hg. WRECKAGE AND IMPACT INFORMATION The main wreckage was resting on the gravel driveway of the pilot's farm, oriented about a 270-degree heading. The wreckage was resting on its right side, and a post crash fire had consumed a majority of the cockpit and fuselage. A debris path was observed, and originated where the tail rotor system was imbedded in the building on the horse farm. The debris path extended about 110 feet, on an approximate bearing of 185 degrees, and terminated at the main wreckage. A light pole was observed about 30 feet along the debris path, and it was severed consistent with main rotor blade contact. The right skid was located about 40 feet along the debris path, and seat cushions were located about 80 feet along the debris path. The tail rotor was recovered from the warehouse roof and examined. One tail rotor blade remained attached, and the other separated about 6 inches from the hub, consistent with impact damage. Continuity was confirmed through the pitch change linkage. Both tail rotor control cables were separated about 12 feet from the pitch change drum, and exhibited broom-straw ends, consistent with overload separation. One of the cables was also separated at the pitch change drum. Due to impact and fire damage, additional tail rotor control cable routing and continuity could not be verified. Both tail rotor blades exhibited some bending and leading edge damage. One main rotor blade exhibited bending near the tip, consistent with striking the light pole. The other exhibited downward bending near the hub. Both blades exhibited minor leading edge damage. Continuity was confirmed from the engine drive, through the transmission, to the main rotor blades and the tail rotor output. The main rotor pitch links were intact; however, continuity could not be confirmed to the cockpit area as multiple pitch change control tubes were consumed by fire. The main rotor clutch assembly was intact, and engaged and disengaged with no abnormalities noted. The main rotor pitch horn attach point was fractured consistent with impact damage. In addition, one arm of the flap restraint system separated, and the collective collar fractured at the base. The tailboom separated about 3 feet aft of the fuselage. Due to impact and fire damage, tail rotor drive shaft continuity could not be confirmed. On July 25, 2006, the engine was removed from the airframe for inspection. The valve covers and sparkplugs were removed from the engine, and oil was observed throughout the engine. The top and bottom sparkplug electrodes were intact, and gray in color; except for the number six top and bottom sparkplugs, which were sooted and oil soaked. The crankshaft was rotated via an accessory gear drive, using a socket wrench. Crankshaft, camshaft, and valve train continuity were confirmed throughout the engine. Thumb compression was attained on all cylinders, except for the number six cylinder. The number six cylinder exhibited charring and bending, consistent with impact and fire damage. Although the cylinder exhibited valve train continuity, the valve springs were relaxed consistent with heat damage. In addition, all cylinders were inspected with a borescope, and no anomalies were noted. The carburetor was removed and inspected, and the floats were found intact. The magnetos were destroyed by fire. MEDICAL AND PATHALOGICAL INFORMATION An autopsy was performed on the pilot by the Lebanon County Coroner's Office, Lebanon, Pennsylvania. Toxicological testing was conducted on the pilot at the FAA Toxicology Accident Research Laboratory, Oklahoma City, Oklahoma. Review of the toxicology report revealed: "...54.94 (ug/ml, ug/g) ACETAMINOPHEN detected in urine." TESTS AND RESEARCH Weight and Balance Review of the helicopter's most recent weight and balance form revealed that it had a useful load of 1,028 lbs. The pilot weighed approximately 145 lbs., and the passenger weighed about 260 lbs. In addition, the pilot fueled the helicopter with 37.5 gallons of 100LL aviation gasoline about 2 hours prior to the accident. The total useable fuel capacity for the helicopter was 57 gallons, or approximately 342 lbs. The weight of the occupants plus full fuel would result in the helicopter being about 280 lbs. less than the maximum gross weight of 2,850 lbs. In addition, the helicopter burned off fuel from the time of the last fueling, until the accident. Hovering Performance Review of performance information in the Rotorcraft Flight Manual Supplement, recovered from the accident helicopter, revealed that: at 2,500 lbs. gross weight, with a temperature of 95 degrees F, in dry air, the out-of-ground-effect hover ceiling was 1,500 feet. At a gross weight of 2,500 lbs., with a temperature of 59 degrees F, in dry air, the out-of-ground-effect hover ceiling was 2,250 feet. At a gross weight of 2,850 pounds, the helicopter could not hover out-of ground-effect under any of the conditions listed on the chart. In addition, the performance information did not contain any data for hovering out-of-ground-effect in a tailwind. Review of FAA-H-8083-21, Rotorcraft Flying Handbook, revealed: "...Wind direction and velocity also effect hovering...Headwinds are most desirable as they contribute to the most increase in performance. Strong crosswinds and tailwinds may require the use of more tail rotor thrust to maintain directional control. This increased tail rotor thrust absorbs power from the engine, which means there is less power available to the main rotor for the production of lift..." ADDITIONAL INFORMATION The wreckage was released to a representative of the owner's insurance company on April 26, 2006.
The pilot's improper decision to hover out-of-ground-effect in a tailwind, and his failure to maintain aircraft control. A factor in the accident was the tailwind.
Source: NTSB Aviation Accident Database
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