Unknown Airport
Aircraft Accident/Incident Report

Vero Beach, Florida 32963
Tuesady, March 12, 1991 9:00 EST

NTSB Narrative Summary Released at Completion of Accident

SHORTLY AFTER TAKEOFF AT 40 FT AGL, THE PLT STATED THAT HE OBSERVED THE HIGH/LOW ROTOR/ENG WARNING LIGHT WAS ILLUMINATED & THE HELICOPTER ENTERED AN UNCOMMANDED RT YAW. HE ENTERED AN AUTOROTATION & WHILE DESCENDING, THE MAIN ROTOR BLADES CONTACTED TREES. HE PULLED COLLECTIVE PITCH BEFORE IMPACT WITH TERRAIN. EXAM OF THE HELICOPTER REVEALED THAT THE UPPER RT TAILBOOM ATTACH BOLT WAS STRIPPED WHICH ALLOWED THE TAILBOOM TO SHIFT RESULTING IN THE SEPARATION OF THE NOS. 1 & 2 TAIL ROTOR DRIVE SHAFT SECTIONS AT THE COUPLING. EXAM OF THE STRIPPED BOLT BY A QUALIFIED INDIVIDUAL REVEALED THAT IT FAILED DUE TO BEING OVERTORQUED. THE COMPANY MECHANIC STATED THAT THE TAILBOOM ATTACH BOLTS ARE CHECKED FOR PROPER TORQUE EVERY 100 HRS & WAS LAST ACCOMPLISHED ABOUT 55 HRS EARLIER.

NTSB Probable Cause Narrative

IMPROPER MAINTENANCE ADJUSTMENT BY COMPANY MAINTENANCE PERSONNEL RESULTING IN OVERTORQUE OF A TAILBOOM ATTACH BOLT WHICH ALLOWED THE TAILBOOM TO SHIFT. THIS DISENGAGED THE TAIL ROTOR DRIVE SHAFT AT A COUPLING RESULTING IN THE LOSS OF TAIL ROTOR DRIVE.

Event Information

Type of Event Accident
Event Date 3/12/1991
Event Day of the Week Tuesday
Time of Event 900
Event Time Zone Eastern Standard Time
Event City VERO BEACH
Event State FLORIDA
Event Country --
Zipcode of the event site 32963
Event Date Year 1991
Event Date Month 3
MidAir Collision Indicator No
On Ground Collision occurred ? No
Event Location Latitude
Event Location Longitude
Event Location Airport UNKNOWN
Event Location Nearest Airport ID NONE
Indicates whether the acc/inc occurred off or on an airport On Airport
Distance from airport in statute miles 0
Degrees magnetic from airport 0
Airport Elevation --
Weather Briefing Completeness Unknown
Investigator's weather source Weather Observation Facility
Time of the weather observation 853 Eastern Standard Time
Direction of event from weather observation facility (degrees) 47
Weather Observation Facility ID VRB
Elevation of weather observation facility 25
Distance of event from weather observation facility (units?) 5
Time Zone of the weather observation EST
Lighting Conditions Day
Lowest Ceiling Height 0
Lowest Non-Ceiling Height 30000
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) 10
Air Temperature at event time (in degrees celsius) 16
Dew Point at event time (in degress fahrenheit) 8
Wind Direction (degrees magnetic) 0
Variable Wind Indicator Unknown
Wind Speed (knots) 0
Wind Velocity Indicator Calm
Wind Gust Indicator Unknown
Wind Gust (knots) 0
Altimeter Setting at event time (in. Hg) 30
Density Altitude (feet) 0
Intensity of Precipitation Unknown
METAR weather report --
Event Highest Injury Minor
On Ground, Fatal Injuries 0
On Ground, Minor Injuries 0
On Ground, Serious Injuries 0
Injury Total Fatal --
Injury Total Minor 1
Injury Total None --
Injury Total Serious --
Injury Total All 1
Investigating Agency NTSB
NTSB Docket Number (internal use) 416
NTSB Notification Source --
NTSB Notification Date --
NTSB Notification Time 0
Fiche Number and/or location -used to find docket information 43703
Date of most recent change to record Dec 12 2000 9:33AM
User who most recently changed record dbo
Basic weather conditions Visual Meteorological Cond
FAA District Office --

Aircraft Involved

Aircraft #1

Aircraft Registration Number N9687R
NTSB Number MIA91LA113
Missing Aircraft Indicator N
Federal Aviation Reg. Part Part 137: Agricultural
Type of Flight Plan filed None
Flight plan Was Activated? --
Damage Substantial
Aircraft Fire None
Aircraft Explosion None
Aircraft Manufacturer's Full Name BELL
Aircraft Model UH-1B
Aircraft Series Identifier UH-1B
Aircraft Serial Number 62-12529
Certified Max Gross Weight 8300
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 2
Number of Engines 1
Fixed gear or retractable gear Fixed
Aircraft, Type of Last Inspection 100 Hour
Date of Last Inspection Aug 28 1990 12:00AM
Airframe hours since last inspection 55
Airframe Hours 7047
ELT Installed No
ELT Activated No
ELT Aided Location of Event Site No
ELT Type --
Aircraft Owner Name COLONY SERVICES, INC.
Aircraft Owner Street Address P. O. BOX 1589
Aircraft Owner City LA BELLE
Aircraft Owner State FL
Aircraft Owner Country
Aircraft Owner Zipcode 33935
Operator is an individual? --
Operator Name COLONY SERVICES, INC.
Operator Same as Owner? Yes
Operator Is Doing Business As --
Operator Address Same as Owner? Yes
Operator Street Address P. O. BOX 1589
Operator City LA BELLE
Operator State FL
Operator Country
Operator Zip code 33935
Operator Code
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) Aerial Application
Second Pilot on Board No
Departure Point Same as Event Yes
Departure Airport Code
Departure City
Departure State
Departure Country
Departure Time 900
Departure Time Zone EST
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 Takeoff
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 --