Aircraft Accident/Incident Report

Tremonton, Utah 84337
Thursday, September 23, 1999 9:00 MDT

NTSB Narrative Summary Released at Completion of Accident

The pilot departed the airport en route to a local staging area to perform aerial application work. He departed with 30 gal. of fuel and was planning to pick up a load of chemical spray at his destination. Approximately 2 1/2 miles southeast of the airport, the engine began to miss. He decided to make a precautionary landing in an alfalfa field. When the helicopter was 200 ft. agl, the engine began to run rougher and he initiated an autorotation. He closed the throttle and the engine quit. The helicopter impacted the ground, stopped suddenly and rocked forward. The rotor blades flexed downward, severing the tail boom. The day following the accident, an examination of the engine was performed by an FAA maintenance inspector and no discrepancies were found. When asked what recommendation the pilot could make as to how the accident could have been prevented, he responded that he could have 'performed [a] better autorotation.'

NTSB Probable Cause Narrative

The pilot's failure to maintain rotor rpm while attempting a precautionary autorotation landing. A factor was the loss of engine power for undetermined reasons.

Event Information

Type of Event Accident
Event Date 9/23/1999
Event Day of the Week Thursday
Time of Event 900
Event Time Zone Mountain Daylight Time
Event City TREMONTON
Event State UTAH
Event Country --
Zipcode of the event site 84337
Event Date Year 1999
Event Date Month 9
MidAir Collision Indicator No
On Ground Collision occurred ? No
Event Location Latitude
Event Location Longitude
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 Not pertinent
Investigator's weather source Weather Observation Facility
Time of the weather observation 851 Mountain Daylight Time
Direction of event from weather observation facility (degrees) 74
Weather Observation Facility ID LGU
Elevation of weather observation facility 4454
Distance of event from weather observation facility (units?) 16
Time Zone of the weather observation MDT
Lighting Conditions Day
Lowest Ceiling Height 0
Lowest Non-Ceiling Height 0
Sky/Lowest/Cloud Conditions Clear
Sky Condition for Lowest Ceiling None
Visibility Runway Visual Range (Feet) 0
Visibility Runway Visual Value (Statute Miles) 0
Visibility (Statute Miles) 10
Air Temperature at event time (in degrees celsius) 11
Dew Point at event time (in degress fahrenheit) 6
Wind Direction (degrees magnetic) 0
Variable Wind Indicator Unknown
Wind Speed (knots) 0
Wind Velocity Indicator Calm
Wind Gust Indicator Not Gusting
Wind Gust (knots) 0
Altimeter Setting at event time (in. Hg) 30
Density Altitude (feet) 4680
Intensity of Precipitation Unknown
METAR weather report --
Event Highest Injury None
On Ground, Fatal Injuries 0
On Ground, Minor Injuries 0
On Ground, Serious Injuries 0
Injury Total Fatal --
Injury Total Minor --
Injury Total None 1
Injury Total Serious --
Injury Total All --
Investigating Agency NTSB
NTSB Docket Number (internal use) 813
NTSB Notification Source --
NTSB Notification Date Sep 23 1999 12:00AM
NTSB Notification Time 1030
Fiche Number and/or location -used to find docket information IMAGE
Date of most recent change to record Dec 12 2000 11:55AM
User who most recently changed record dbo
Basic weather conditions Visual Meteorological Cond
FAA District Office --

Aircraft Involved

Aircraft #1

Aircraft Registration Number N83246
NTSB Number DEN99LA168
Missing Aircraft Indicator N
Federal Aviation Reg. Part Part 137: Agricultural
Type of Flight Plan filed Company VFR
Flight plan Was Activated? --
Damage Substantial
Aircraft Fire None
Aircraft Explosion None
Aircraft Manufacturer's Full Name Bell
Aircraft Model 47G3B2A
Aircraft Series Identifier 47G3B2A
Aircraft Serial Number 6858
Certified Max Gross Weight 2950
Aircraft Category Helicopter
Aircraft Registration Class U.S. Registered/U.S. Soil
Aircraft is a homebuilt? No
Flight Crew Seats --
Cabin Crew Seats --
Passenger Seats --
Total number of seats on the aircraft 3
Number of Engines 1
Fixed gear or retractable gear Fixed
Aircraft, Type of Last Inspection 100 Hour
Date of Last Inspection Aug 11 1999 12:00AM
Airframe hours since last inspection 13
Airframe Hours 9912
ELT Installed Yes
ELT Activated No
ELT Aided Location of Event Site Unknown
ELT Type --
Aircraft Owner Name BRENT V. WOOD
Aircraft Owner Street Address 437 N. TREMONT ST.
Aircraft Owner City TREMONTON
Aircraft Owner State UT
Aircraft Owner Country
Aircraft Owner Zipcode 84337
Operator is an individual? --
Operator Name
Operator Same as Owner? Yes
Operator Is Doing Business As --
Operator Address Same as Owner? Yes
Operator Street Address
Operator City
Operator State
Operator Country
Operator Zip code
Operator Code DYWG
Owner has at least one certificate Yes - certificate holder
Other Operator of large aircraft? No
Certified for Part 133 or 137 Operation Agriculture
Operator Certificate Number --
Indicates whether an air carrier operation was scheduled or not Unknown
Indicates Domestic or International Flight Unknown
Operator carrying Pax/Cargo/Mail Unknown
Type of Flying (Per_Bus / Primary) Ferry
Second Pilot on Board No
Departure Point Same as Event Yes
Departure Airport Code U27
Departure City
Departure State UT
Departure Country
Departure Time 855
Departure Time Zone MDT
Destination Same as Local Flt --
Destination Airport Code NONE
Destination City COALVILLE
Destination State UT
Destination Country
Specific Phase of Flight Cruise
Report sent to ICAO? --
Evacuation occurred --
Date of most recent change to record Jan 2 2001 10:35AM
User who most recently changed record dbo
Since inspection or accident --
Event Location Runway Number and Location 0
Runway Length --
Runway Width --
Sight Seeing flight No
Air Medical Flight No
Medical Flight --