R22 downed by kite?
NTSB Identification: NYC04FA197
14 CFR Part 91: General Aviation
Accident occurred Sunday, August 29, 2004 in Northport, NY
Aircraft: Robinson R-22, registration: N871CL
Injuries: 2 Fatal.
This is preliminary information, subject to change, and may contain errors. Any errors in this report will be corrected when the final report has been completed.
On August 29, 2004, about 1802 eastern daylight time, a Robinson R-22, N871CL, was substantially damaged when it impacted water near Northport, New York. The certificated flight instructor, and private pilot were fatally injured. Day visual meteorological conditions prevailed for the local instructional flight that departed Long Island Mac Arthur Airport (ISP), Islip, New York, about 1715. No flight plan was filed, and the flight was conducted under 14 CFR Part 91.
According to radar data, a target matching the performance characteristics of the accident helicopter and "squawking 1200," was flying east along the north shore of Long Island, New York, approximately 600 feet agl. The target then initiated a descent and radar contact was lost approximately 300 feet agl. Several minutes later, radar contact was reestablished, and the target continued to proceed eastbound about 600 feet agl. In the vicinity of the accident site and about 2 minutes before the accident, radar contact was lost.
According to a witness that was laying on the beach watching a kite, the helicopter approached from the west along the shoreline 100 to 160 feet agl. The witness then saw the helicopter collide with the kite, the main rotor system separate, and about a second later, heard a loud "pop," which he described as sounding like a "balloon popping but much louder." The helicopter then started to rotate rapidly counter clockwise and impacted the water. The witness added that the kite was a red single line delta wing 2 to 3 feet in span, and had a gold tail approximately 2 feet in length. The witness also recovered the kite string minus the kite and gave it to local authorities.
According to another witness that was sea kayaking about 300 feet from the shoreline and about 200 feet from the accident site, he watched the helicopter approach from the west about 200 feet agl. He then heard a "loud crack noise," and saw the main rotor system "snap off." The helicopter then entered an uncontrolled descent and the witness heard engine rpm increase. The witness added that the wind was approximately 7 knots out of the south, and the sky was clear, except for "perhaps a few clouds." In his written statement, the witnessed made no mention of a kite. Other witnesses interviewed reported a kite flying at the time of the accident, but could not recall if the helicopter contacted it or not.
The accident occurred during the hours of daylight. The wreckage was located about 80 feet from the shoreline in approximately 3 feet of water at 40 degrees, 55.700 minutes north latitude, 73 degrees, 20.500 minutes west longitude.
The instructor held a commercial pilot certificate with a helicopter rating, along with a flight instructor rating for helicopters. His last Federal Aviation Administration (FAA) second-class medical certificate was issued on April 19, 2004, and the instructor had approximately 332 hours of total flight experience, all of which was in rotorcraft. In addition, the instructor had worked for the helicopter operator for approximately 3 weeks and during that time frame flew approximately 92 hours, with 10 hours being within 24 hours of the accident.
The pilot receiving instruction held a private pilot certificate with an airplane single-engine-land, and helicopter rating. On his last FAA third-class medical certificate, which was dated July 24, 1997, he reported a total flight experience of 135 hours. According to the operator, the pilot had 132.5 hours with 10 hours being in the last 30 days.
A weather observation was taken about 4 minutes after the accident at the Republic Airport (FRG), Farmingdale, New York, which had a field elevation of 82 feet msl, and was located approximately 14 miles to the southwest of the accident site. The weather was recorded as wind 200 degrees at 11 knots, visibility 10 miles, ceiling 1,200 feet broken, temperature 54 degrees Fahrenheit, dew point 34 degrees Fahrenheit, and an altimeter setting of 29.83 inches of mercury.
The wreckage was recovered to a police impound yard the night of the accident. The main rotor hub, and both associated blades were not recovered, and a subsequent search to locate them was unsuccessful.
Examination of the main wreckage revealed that impact damage was greater towards the front of the helicopter. The cockpit displayed damage consistent with impact and main rotor blade contact. The engine and transmission area cowlings displayed impact damage. The tailboom displayed impact damage, but no damage consistent with main rotor blade contact was observed. The tail rotor gearbox was attached and both tail rotor blades had separated approximately 1 inch outboard of the blade grips. Flight control continuity was confirmed from the cockpit to the main rotor pitch change links and to the tail rotor blades. The fracture surfaces for both main rotor system pitch change links were deformed and a 45-degree shear lip.
Examination of the main transmission revealed the case and mounts were intact, and no noticeable deformation to the supporting structure was observed. A rotational force was applied to the input drive of the transmission, and the mast rotated. Drive train continuity was confirmed from the engine to the main transmission, and to the tail rotor gearbox. The main rotor mast had separated approximately 1 inch below the main rotor hub. The fracture surface was deformed, and had a 45-degree shear lip.
Examination of the fuel system revealed that continuity could not be confirmed because of impact damage. The fuel selector was in the "On" position. The carburetor was removed from the engine to facilitate the examination. The throttle plate, along with all the carburetor subsystems were intact, and other than saltwater, no contaminants were identified in the system.
Examination of the ignition system revealed the ignition switch was in the "Both" position. The left magneto was attached to the engine case and the right had separated. The left was removed, and the point access covers for both magnetos were opened. Once the points were dry, a rotational forced was applied. Spark was observed on all four left magneto towers, but not on any of the right magneto. Continuity of the ignition leads from both magnetos to the respective sparkplugs could not be confirmed because of impact damage. The sparkplugs were removed, and contaminants ranging from oil, to rust, to sludge, were identified.
Examination of the engine revealed impact damage to several valve covers, and the air induction, along with the engine exhaust system. Engine control continuity was confirmed from the cockpit to the carburetor and carburetor heat box. A rotational force was applied to the engine crankshaft, compression was obtained on all four cylinders, the accessory gears rotated, and valve train continuity was confirmed. The oil induction screen was removed, and absent of debris. Saltwater and sludge were in the oil system, but nothing metallic was identified.
According to the pilot's operator handbook, "Pushing the cyclic forward following a pull-up or rapid climb, or even from level flight, produces a low-G (weightless) flight condition. If the helicopter is still pitching forward when the pilot applies aft cyclic to reload the rotor, the rotor disk may tilt aft relative to the fuselage before it is reload. The main rotor torque reaction will then combine with tail rotor thrust to produce a powerful right rolling moment on the fuselage. With no lift from the rotor, there is no lateral control to stop the rapid right role and mast bumping can occur. Severe in-flight mast bumping usually results in main rotor shaft separation and/or rotor blade contact with the fuselage."
The wreckage was released to the owner on August 1, 2004.