Date:	Tuesday 5 June 1990
Time:	09:15
Type:	Hughes 369HS
Owner/operator:	Helicopter Minit Men, Inc.
Registration:	N8315F
MSN:	360801S
Year of manufacture:	1976
Engine model:	ALLISON 250-C20
Fatalities:	Fatalities: 0 / Occupants: 3
Other fatalities:	0
Aircraft damage:	Destroyed
Category:	Accident
Location:	Brookville, PA -   United States of America
Phase:	Manoeuvring (airshow, firefighting, ag.ops.)
Nature:	Survey
Departure airport:
Destination airport:
Investigating agency:	NTSB
Confidence Rating:	Accident investigation report completed and information captured

Narrative:
During a power line patrol flight over wooded terrain, at about 60 to 85 ft agl, tail rotor control of was lost. The helicopter began to spin to the right and the pilot attempted a hovering autorotation. The helicopter began spinning faster. Subsequently, it settled onto the power line, then crashed to the ground.

An examination revealed that the tail rotor swash plate had failed from fatigue. The swash plate outer diameter was worn with evidence of spalling, the bearing inner diameter was lightly scored, the swash plate threads were severely worn with evidence of spalling due to relative motion with the mating threads of the lock nut and the lock washer tang had worn a significant pattern in the swash plate key way.

The NTSB determined the probable cause to be: Worn tail rotor pitch control assembly, due to improper maintenance/installation, and subsequent fatigue failure of the tail rotor swashplate

1. NTSB Identification: NYC90LA125 at https://www.ntsb.gov/_layouts/ntsb.aviation/brief.aspx?ev_id=20001212X23519&key=1&queryId=eca1f985-c12d-400a-9201-c4f552d77628&pgsize=100
2. FAA: http://registry.faa.gov/aircraftinquiry/NNum_Results.aspx?omni=Home-N-Number&nNumberTxt=8315F
3. http://www.griffin-helicopters.co.uk/accidentdetails.aspx?accidentkey=11040

Date/time	Contributor	Updates
21-Aug-2016 00:11	Dr.John Smith	Updated [Cn, Source, Narrative, ]
21-Dec-2016 19:25	ASN Update Bot	Updated [Time, Damage, Category, Investigating agency, ]