Aircraft Accident/Incident Report

Lucerne Valley, California 92356
Tuesady, August 4, 1998 7:45 PDT

NTSB Narrative Summary Released at Completion of Accident

The pilot had been flying for about 25 minutes when he noticed that the oil pressure gauge and torque gauge were fluctuating. He initiated an approach to a precautionary landing spot on an asphalt pad. About 150 feet agl, the engine quit and the pilot autorotated to touch down on a paved road. The main rotor blades severed the tail boom aft of the horizontal stabilizer. The engine had received some maintenance work and had been reinstalled in the helicopter the night before the accident, at which time the pilot performed a test run and leak check of the engine, with no noted discrepancies. The pilot further stated that the engine had been running normally until the fluctuation of the oil pressure and torque gauges. During an examination of the engine, the oil output line was connected, but loose, and oil was seen dripping from the fitting area. Oil was observed over most of the fuselage and underneath the engine. There was approximately 1 pint of oil found in the sump. Further teardown of the engine revealed that the number 8 bearing was destroyed and no oil was found throughout the lubrication system. The Bell Helicopter maintenance manual specifies a torque value for the fitting on the oil output line; however, the mechanic who installed the engine reported that he did not use a torque wrench to tighten the line because he would have had to remove some other lines to get to it and he was in a hurry.

NTSB Probable Cause Narrative

The failure of the mechanic who installed the engine to follow proper procedures by insuring the proper torque to the oil output line, resulting in a loose fitting, oil loss and subsequent bearing failure.

Event Information

Type of Event Accident
Event Date 8/4/1998
Event Day of the Week Tuesday
Time of Event 745
Event Time Zone Pacific Daylight Time
Event City LUCERNE VALLEY
Event State CALIFORNIA
Event Country --
Zipcode of the event site 92356
Event Date Year 1998
Event Date Month 8
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 749 Pacific Daylight Time
Direction of event from weather observation facility (degrees) 360
Weather Observation Facility ID DAG
Elevation of weather observation facility 1927
Distance of event from weather observation facility (units?) 34
Time Zone of the weather observation PDT
Lighting Conditions Day
Lowest Ceiling Height 0
Lowest Non-Ceiling Height 22000
Sky/Lowest/Cloud Conditions Scattered
Sky Condition for Lowest Ceiling None
Visibility Runway Visual Range (Feet) 0
Visibility Runway Visual Value (Statute Miles) 0
Visibility (Statute Miles) 35
Air Temperature at event time (in degrees celsius) 31
Dew Point at event time (in degress fahrenheit) 10
Wind Direction (degrees magnetic) 280
Variable Wind Indicator Unknown
Wind Speed (knots) 10
Wind Velocity Indicator Unknown
Wind Gust Indicator Not Gusting
Wind Gust (knots) 0
Altimeter Setting at event time (in. Hg) 30
Density Altitude (feet) --
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) 1443
NTSB Notification Source --
NTSB Notification Date Aug 4 1998 12:00AM
NTSB Notification Time 822
Fiche Number and/or location -used to find docket information IMAGE
Date of most recent change to record Dec 11 2000 11:42AM
User who most recently changed record dbo
Basic weather conditions Visual Meteorological Cond
FAA District Office --

Aircraft Involved

Aircraft #1

Aircraft Registration Number N5016G
NTSB Number LAX98LA256
Missing Aircraft Indicator N
Federal Aviation Reg. Part Part 91: General Aviation
Type of Flight Plan filed VFR
Flight plan Was Activated? --
Damage Substantial
Aircraft Fire None
Aircraft Explosion None
Aircraft Manufacturer's Full Name Bell
Aircraft Model 206B
Aircraft Series Identifier 206B
Aircraft Serial Number 2624
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 Annual
Date of Last Inspection May 1 1998 12:00AM
Airframe hours since last inspection 68
Airframe Hours 5788
ELT Installed Yes
ELT Activated No
ELT Aided Location of Event Site Unknown
ELT Type --
Aircraft Owner Name RAINBOW HELICOPTERS
Aircraft Owner Street Address P.O. BOX 863
Aircraft Owner City REDMOND
Aircraft Owner State OR
Aircraft Owner Country
Aircraft Owner Zipcode 97756
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 QRNA
Owner has at least one certificate Yes - certificate holder
Other Operator of large aircraft? No
Certified for Part 133 or 137 Operation External Load
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) Positioning
Second Pilot on Board No
Departure Point Same as Event No
Departure Airport Code RAL
Departure City RIVERSIDE
Departure State CA
Departure Country
Departure Time 720
Departure Time Zone PDT
Destination Same as Local Flt --
Destination Airport Code FLG
Destination City FLAGSTAFF
Destination State AZ
Destination Country
Specific Phase of Flight Cruise
Report sent to ICAO? --
Evacuation occurred --
Date of most recent change to record Jan 2 2001 10:34AM
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 --