Accident Hughes 269C N1093N,
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ASN Wikibase Occurrence # 354864
 
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Date:Thursday 22 January 1998
Time:12:15 LT
Type:Silhouette image of generic H269 model; specific model in this crash may look slightly different    
Hughes 269C
Owner/operator:Private
Registration: N1093N
MSN: 100882
Year of manufacture:1980
Total airframe hrs:2829 hours
Engine model:Lycoming HIO-360-D1A
Fatalities:Fatalities: 0 / Occupants: 2
Aircraft damage: Substantial
Category:Accident
Location:Brackettville, TX -   United States of America
Phase: En route
Nature:Unknown
Departure airport:Bacon Ranch, TX
Destination airport:
Investigating agency: NTSB
Confidence Rating: Accident investigation report completed and information captured
Narrative:
The pilot and a crewmember/gunner of the public use helicopter reported hearing a loud squealing noise, emanating from the rear of the helicopter, while in flight at 75 feet AGL. Rotor RPM began decaying from 3,100 to approximately 2,000 RPM, and the pilot initiated an autorotation. During the landing, the main rotor blades contacted the ground, and helicopter came to rest in a rocky dry creek bed on its right side. The tension nut for the short shaft was found upstream from the point of impact. An examination revealed that splines for the drive shaft coupling were damaged, and the plating on the adapter was discolored as result of excessive heat. Further examination revealed that the damage sustained by the shaft and adapter were consistent with loss of grease and subsequent overheating and destruction of the drive splines. The forward rubber boot, used to retain the lubricant, had separated, resulting in the loss of lubrication.

Probable Cause: failure of splines on the drive shaft coupling after separation of the forward bubber boot and loss of lubrication (grease), which resulted in a disconnect of the rotor drive system and an autorotation/forced landing. Lack of suitable terrain in the forced landing area was a related factor.

Accident investigation:
cover
  
Investigating agency: NTSB
Report number: FTW98TA104
Status: Investigation completed
Duration: 9 months
Download report: Final report

Sources:

NTSB FTW98TA104

Location

Revision history:

Date/timeContributorUpdates
11-Mar-2024 19:11 ASN Update Bot Added

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