Aircraft Accident/Incident Report

Tucson, Arizona 85706
Monday, October 25, 2004 14:25 MST

NTSB Narrative Summary Released at Completion of Accident

The engine spooled down during a law enforcement surveillance flight, and the pilot made a hard forced landing in uneven terrain. The crew was performing surveillance at low altitude above an uneven wash, and the pilot was in slow sideward flight. He pulled the collective to gain altitude and airspeed to make another pass. Then he heard and felt the engine spool down. He said that it quit producing power completely, and he attempted to autorotate to the ground. He said that he had insufficient airspeed and altitude to complete a successful autorotation. The helicopter hit the ground hard in a near level attitude. It bounced backwards, and rotated 45 degrees to the right. Metallurgical examination revealed that the governor tee to fuel control PC line fractured as a result of fatigue. The tubes were bent with contours differing from the original manufactured shape, indicative of handling/assembly damage. Disassembly and inspection of the starter/generator revealed conditions indicative of wear and misassembly, including the wrong bearings being installed, which would cause the unit to operate in an out-of-balance condition and induce vibrations.

NTSB Probable Cause Narrative

The loss of engine power due to a fatigue fracture of the PC line from the governor to fuel control, resulting from fretting damage induced by excessive vibration, which was due to the failure of maintenance personnel to install the proper bearings in the starter/generator. A contributing factor was the loss of power at low altitude and airspeed (height/velocity limitation) which diminished the possibility of a successful autorotation.

Event Information

Type of Event Accident
Event Date 10/25/2004
Event Day of the Week Monday
Time of Event 1425
Event Time Zone Mountain Standard Time
Event City Tucson
Event State ARIZONA
Event Country --
Zipcode of the event site 85706
Event Date Year 2004
Event Date Month 10
MidAir Collision Indicator No
On Ground Collision occurred ? No
Event Location Latitude 320023N
Event Location Longitude 1113915W
Event Location Airport --
Event Location Nearest Airport ID --
Indicates whether the acc/inc occurred off or on an airport Off Airport/Airstrip
Distance from airport in statute miles --
Degrees magnetic from airport --
Airport Elevation --
Weather Briefing Completeness --
Investigator's weather source Weather Observation Facility
Time of the weather observation 1355 Mountain Standard Time
Direction of event from weather observation facility (degrees) --
Weather Observation Facility ID TUS
Elevation of weather observation facility --
Distance of event from weather observation facility (units?) --
Time Zone of the weather observation MST
Lighting Conditions Day
Lowest Ceiling Height --
Lowest Non-Ceiling Height 8000
Sky/Lowest/Cloud Conditions Scattered
Sky Condition for Lowest Ceiling None
Visibility Runway Visual Range (Feet) --
Visibility Runway Visual Value (Statute Miles) --
Visibility (Statute Miles) 10
Air Temperature at event time (in degrees celsius) 25
Dew Point at event time (in degress fahrenheit) 12
Wind Direction (degrees magnetic) 290
Variable Wind Indicator Wind direction could be determined
Wind Speed (knots) 8
Wind Velocity Indicator --
Wind Gust Indicator Not Gusting
Wind Gust (knots) --
Altimeter Setting at event time (in. Hg) 29.8
Density Altitude (feet) --
Intensity of Precipitation --
METAR weather report --
Event Highest Injury Serious
On Ground, Fatal Injuries --
On Ground, Minor Injuries --
On Ground, Serious Injuries --
Injury Total Fatal --
Injury Total Minor --
Injury Total None --
Injury Total Serious 2
Injury Total All 2
Investigating Agency NTSB
NTSB Docket Number (internal use) 21962
NTSB Notification Source FAA
NTSB Notification Date Oct 25 2004 12:00AM
NTSB Notification Time --
Fiche Number and/or location -used to find docket information DMS
Date of most recent change to record Jul 25 2007 12:22PM
User who most recently changed record NTSB\lema
Basic weather conditions Visual Meteorological Cond
FAA District Office WP-SDL-FSDO

Aircraft Involved

Aircraft #1

Aircraft Registration Number N6188L
NTSB Number LAX05TA018
Missing Aircraft Indicator --
Federal Aviation Reg. Part Public Use
Type of Flight Plan filed Company VFR
Flight plan Was Activated? Yes
Damage Destroyed
Aircraft Fire None
Aircraft Explosion None
Aircraft Manufacturer's Full Name Hughes
Aircraft Model OH-6A
Aircraft Series Identifier --
Aircraft Serial Number 891257
Certified Max Gross Weight 2550
Aircraft Category Helicopter
Aircraft Registration Class --
Aircraft is a homebuilt? No
Flight Crew Seats --
Cabin Crew Seats --
Passenger Seats --
Total number of seats on the aircraft 2
Number of Engines 1
Fixed gear or retractable gear Fixed
Aircraft, Type of Last Inspection AAIP
Date of Last Inspection Oct 1 2004 12:00AM
Airframe hours since last inspection 8.6
Airframe Hours 9463.3
ELT Installed Yes
ELT Activated Yes
ELT Aided Location of Event Site No
ELT Type --
Aircraft Owner Name Department of Homeland Security Bureau of Customs
Aircraft Owner Street Address 9C Butterfield Trail
Aircraft Owner City El Paso
Aircraft Owner State TX
Aircraft Owner Country USA
Aircraft Owner Zipcode 79906
Operator is an individual? No
Operator Name Tucson Sector Air Operations
Operator Same as Owner? No
Operator Is Doing Business As --
Operator Address Same as Owner? No
Operator Street Address 2020 E. Airport Drive
Operator City Tucson
Operator State AZ
Operator Country USA
Operator Zip code 85706
Operator Code --
Owner has at least one certificate None
Other Operator of large aircraft? --
Certified for Part 133 or 137 Operation --
Operator Certificate Number --
Indicates whether an air carrier operation was scheduled or not --
Indicates Domestic or International Flight --
Operator carrying Pax/Cargo/Mail --
Type of Flying (Per_Bus / Primary) Public Use
Second Pilot on Board No
Departure Point Same as Event No
Departure Airport Code --
Departure City Ajo
Departure State AZ
Departure Country USA
Departure Time 1100
Departure Time Zone MST
Destination Same as Local Flt crash at destination city
Destination Airport Code TUS
Destination City Tucson
Destination State AZ
Destination Country USA
Specific Phase of Flight Maneuvering
Report sent to ICAO? No
Evacuation occurred No
Date of most recent change to record Jul 23 2007 1:27PM
User who most recently changed record COOS
Since inspection or accident Time of Accident
Event Location Runway Number and Location NA
Runway Length --
Runway Width --
Sight Seeing flight No
Air Medical Flight No
Medical Flight --