ASN Wikibase Occurrence # 39406
Last updated: 7 December 2016
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Narrative:On May 5, 1985, at approximately 16:30 CDT (Central Daylight Time) a Robinson R22, N83745, operated by American Helicopters, Inc., broke up in flight during a practice flight 3 miles south of San Angelo, Texas. The commercial helicopter pilot, who was preparing to take a certified flight instructor (CFI) helicopter check flight, and a passenger were killed.
Robinson R22 Beta
|Owner/operator:||American Helicopters Inc|
|C/n / msn:|| 0320|
|Fatalities:||Fatalities: 2 / Occupants: 2|
|Airplane damage:|| Written off (damaged beyond repair)|
|Location:||3 miles South of San Angelo, Texas -
United States of America
|Phase:|| En route|
|Departure airport:||San Angelo, Texas (SJT/KSJT)|
The pilot had accumulated 2,433 total flight hours, 133 of which were in helicopters and 115 in the R22. The helicopter, including the fuselage, engine, transmission, and skids, came to rest on its left side, with considerable crushing to the fuselage. Portions of the fragmented windshield and tail boom came to rest in a soft plowed field 1,200 feet west of the main wreckage, along the helicopter's flight path. The tail rotor gear box was located approximately 600 feet west of the main wreckage.
Reconstruction of the tail boom showed that a main rotor blade had struck the tail boom at three separate locations. The first strike occurred approximately 2 feet forward of the tail rotor. The second and third strikes were measured at 4 feet from the tail rotor, and 2 feet from the tail boom attachment to the fuselage. The tail rotor driveshaft and tail rotor push-pull tubes were severely bent and exhibited a strike from a main rotor blade. Both main rotor blades contained multiple areas of blue paint transfer, leading and trailing edge damage, and chord wise scratches on the surface of the blades.
The main rotor mast separated in overload at the upper transmission cap. The upper main rotor mast and hub assembly remained intact with the spindles attached to the hub and the blade horns secured to the main rotor blades. The transmission and free-wheeling unit were free to turn manually with no binding or anomalies. Disassembly of the engine revealed no evidence of mechanical malfunction, and the carburetor throttle was observed in the full open position.
Examination of the collective and cyclic control tubes revealed overload fractures due to impact and no evidence of fatigue or pre-impact failure. The NTSB was unable to define the event that caused the main rotor blades to divert from their normal plane of rotation and strike the tail boom.
1. NTSB Identification: FTW85FA207 at http://www.ntsb.gov/_layouts/ntsb.aviation/brief.aspx?ev_id=20001214X36448&key=1
2. FAA: http://registry.faa.gov/aircraftinquiry/NNum_Results.aspx?omni=Home-N-Number&nNumberTxt=83745
||Updated [Time, Location, Source, Narrative]|
||Updated [Aircraft type, Departure airport, Source, Narrative]|
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