Aircraft Accident/Incident Report

Hilo, Hawaii 96720
Saturday, September 29, 2001 14:23 HST

NTSB Narrative Summary Released at Completion of Accident

The pilot made a mayday call, shut off the fuel valve, and performed an autorotation into high grass after the single engine helicopter experienced a loss of engine power shortly after takeoff. The pilot had heard a bang followed by illumination of the engine out warning light, and the engine began smoking. During the terminal phase of the autorotation, the pilot assumed the grass height was 3 feet and flared accordingly; however, the grass was at least 6 feet tall. Post-accident examination of the engine revealed that the No. 1 turbine wheel was missing. The No. 8 bearing thrust nut exhibited a locking indentation and a notch on its inside surface. Additionally, indentations were on the threads of the threaded end of the first stage turbine wheel shaft. These marks suggest that the thrust nut was not fully engaged on the first stage turbine shaft. The location of the notch suggests that the edge of the nut protruded beyond the end of the turbine shaft. There were no indications of contact by the shaft threads on the inner surface of the deformed area to suggest that it had been displaced into a groove on the first stage turbine shaft. Review of the maintenance records and interviews with the mechanic, who performed the most recent maintenance work, revealed that the turbine section had been replaced approximately 30 hours prior to the accident. Due to excessive oil consumption, maintenance personnel removed the turbine and replaced the No. 5 carbon seal approximately 14 hours prior to the accident. The maintenance records indicated that the day before the accident, the sump cover had been removed for trouble shooting oil consumption. Though it is not detailed in the maintenance entry, it is interpreted that the "sump cover" referred to is the No. 8 Bearing sump nut since the thrust nut was loose.

NTSB Probable Cause Narrative

The failure of the mechanic to secure the No. 8 bearing thrust nut during maintenance work, which resulted in the total failure of the first stage turbine wheel shaft. Also causal was his misjudgment of his height during the flare resulting in a hard landing. A contributing factor was the high vegetation in the forced landing field, which resulted in a hard landing.

Event Information

Type of Event Accident
Event Date 9/29/2001
Event Day of the Week Saturday
Time of Event 1423
Event Time Zone Hawaii Standard Time
Event City Hilo
Event State HAWAII
Event Country --
Zipcode of the event site 96720
Event Date Year 2001
Event Date Month 9
MidAir Collision Indicator No
On Ground Collision occurred ? No
Event Location Latitude 193826N
Event Location Longitude 1520205W
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 Unknown
Investigator's weather source Weather Observation Facility
Time of the weather observation 1353 Hawaii Standard Time
Direction of event from weather observation facility (degrees) --
Weather Observation Facility ID PHTO
Elevation of weather observation facility 38
Distance of event from weather observation facility (units?) 5
Time Zone of the weather observation HST
Lighting Conditions Day
Lowest Ceiling Height --
Lowest Non-Ceiling Height 2900
Sky/Lowest/Cloud Conditions Few
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) 28
Dew Point at event time (in degress fahrenheit) 20
Wind Direction (degrees magnetic) 10
Variable Wind Indicator Wind direction could be determined
Wind Speed (knots) 9
Wind Velocity Indicator --
Wind Gust Indicator Not Gusting
Wind Gust (knots) --
Altimeter Setting at event time (in. Hg) 29.98
Density Altitude (feet) --
Intensity of Precipitation --
METAR weather report --
Event Highest Injury Minor
On Ground, Fatal Injuries --
On Ground, Minor Injuries --
On Ground, Serious Injuries --
Injury Total Fatal --
Injury Total Minor 2
Injury Total None 3
Injury Total Serious --
Injury Total All 2
Investigating Agency NTSB
NTSB Docket Number (internal use) 15529
NTSB Notification Source FAA
NTSB Notification Date Sep 29 2001 12:00AM
NTSB Notification Time 1752
Fiche Number and/or location -used to find docket information DMS
Date of most recent change to record Jun 3 2004 1:28PM
User who most recently changed record NTSB\MONR
Basic weather conditions Visual Meteorological Cond
FAA District Office WP-HNL-FSDO

Aircraft Involved

Aircraft #1

Aircraft Registration Number N206KS
NTSB Number LAX01FA306
Missing Aircraft Indicator --
Federal Aviation Reg. Part Part 135: Air Taxi & Commuter
Type of Flight Plan filed Company VFR
Flight plan Was Activated? No
Damage Destroyed
Aircraft Fire Ground
Aircraft Explosion None
Aircraft Manufacturer's Full Name Bell
Aircraft Model 206B
Aircraft Series Identifier --
Aircraft Serial Number 2457
Certified Max Gross Weight 3200
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 5
Number of Engines 1
Fixed gear or retractable gear Fixed
Aircraft, Type of Last Inspection 100 Hour
Date of Last Inspection Sep 20 2001 12:00AM
Airframe hours since last inspection 5441.5
Airframe Hours 5456.5
ELT Installed Yes
ELT Activated Unknown
ELT Aided Location of Event Site No
ELT Type --
Aircraft Owner Name K&S Helicopters, Inc.
Aircraft Owner Street Address Main Airport Terminal
Aircraft Owner City Hilo
Aircraft Owner State HI
Aircraft Owner Country USA
Aircraft Owner Zipcode 96720
Operator is an individual? No
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 K2DA
Owner has at least one certificate --
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 Non-scheduled
Indicates Domestic or International Flight Domestic
Operator carrying Pax/Cargo/Mail Passenger Only
Type of Flying (Per_Bus / Primary) --
Second Pilot on Board No
Departure Point Same as Event Yes
Departure Airport Code ITO
Departure City HILO
Departure State HI
Departure Country USA
Departure Time 1420
Departure Time Zone HST
Destination Same as Local Flt dest & departure same, accident can occur anywhere
Destination Airport Code --
Destination City --
Destination State --
Destination Country --
Specific Phase of Flight Cruise
Report sent to ICAO? Yes
Evacuation occurred Yes
Date of most recent change to record Mar 23 2004 4:49PM
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 Yes
Air Medical Flight No
Medical Flight --