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ASN Wikibase Occurrence # 39406
Last updated: 29 June 2016
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Date:05-MAY-1985
Time:16:30 CDT
Type:Silhouette image of generic R22 model; specific model in this crash may look slightly different
Robinson R22 HP
Owner/operator:American Helicopters Inc
Registration: N83745
C/n / msn: 0320
Fatalities:Fatalities: 2 / Occupants: 2
Other fatalities:0
Airplane damage: Written off (damaged beyond repair)
Location:3 miles South of San Angelo, Texas -   United States of America
Phase: En route
Nature:Private
Departure airport:San Angelo, TX (SJT)
Destination airport:
Narrative:
On May 5, 1985, at approximately 1630 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.

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 tailboom came to rest in a soft plowed field 1,200 feet west of the main wreckage, along the helicopter's flightpath. The tailrotor gear box was located approximately 600 feet west of the main wreckage.

Reconstruction of the tailboom showed that a main rotor blade had struck the tailboom 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 tailboom 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 chordwise 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 preimpact failure. The Safety Board was unable to define the event that caused the main rotor blades to divert from their normal plane of rotation and strike the tailboom.

Sources:
1. NTSB Identification: FTW85FA207: http://www.ntsb.gov/ntsb/brief.asp?ev_id=20001214X36448
2. Faa: http://registry.faa.gov/aircraftinquiry/NNum_Results.aspx?omni=Home-N-Number&nNumberTxt=83745


Revision history:

Date/timeContributorUpdates
24-Oct-2008 10:30 ASN archive Added
07-Feb-2016 22:02 Dr.John Smith Updated [Time, Location, Source, Narrative]
Number of views: 1092

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