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NTSB Report
December 10, 1991 · Bell 206L-3+ · N2770X
Arlington, TX
Overview
Report Status
Probable Cause
Event Type
Accident
Date
December 10, 1991
Injury Outcomes
No injuries (2 uninjured)
Location
Arlington, TX
Aircraft
Bell 206L-3+
Tail Number
N2770X
Operator
Bell Helicopter Textron
Injuries
None
Aircraft Damage
Substantial
NTSB Number
FTW92LA040
THE EXPERIMENTAL CERTIFICATED HELICOPTER WAS BEING TEST FLOWN AS PART OF THE HEIGHT VELOCITY DIAGRAM DEVELOPMENT FOR THE 206L4 CERTIFICATION PROGRAM. THE TEST PILOT WAS CONDUCTING ABORTED TAKEOFFS WHEN AT 30 FEET AND 50 KNOTS HE INITIATED AN AUTOROTATION. THE COLLECTIVE WAS LOWERED SLIGHTLY AND A HIGH DESCENT RATE OCCURRED. DURING THE DESCENT THE MAIN ROTOR RPM DECREASED AND THE HELICOPTER LANDED HARD RESULTING IN TAILBOOM BUCKLING AND SEPARATION OF THE TAIL ROTOR DRIVE SHAFT. THE PILOT'S APPLICATION OF COLLECTIVE BEFORE TOUCHDOWN DID NOT ARREST THE DESCENT RATE.
NTSB Probable Cause
THE HELICOPTER'S AUTOROTATIONAL LANDING PERFORMANCE CAPABILITY WAS EXCEEDED. FACTORS WERE THE PROPER DESCENT RATE WAS NOT POSSIBLE FOR THE PIC AND SUFFICIENT INFORMATION FROM THE MANUFACTURER WAS NOT PROVIDED.
Full Narrative
THE EXPERIMENTAL CERTIFICATED HELICOPTER WAS BEING TEST FLOWN AS PART OF THE HEIGHT VELOCITY DIAGRAM DEVELOPMENT FOR THE 206L4 CERTIFICATION PROGRAM. THE TEST PILOT WAS CONDUCTING ABORTED TAKEOFFS WHEN AT 30 FEET AND 50 KNOTS HE INITIATED AN AUTOROTATION. THE COLLECTIVE WAS LOWERED SLIGHTLY AND A HIGH DESCENT RATE OCCURRED. DURING THE DESCENT THE MAIN ROTOR RPM DECREASED AND THE HELICOPTER LANDED HARD RESULTING IN TAILBOOM BUCKLING AND SEPARATION OF THE TAIL ROTOR DRIVE SHAFT. THE PILOT'S APPLICATION OF COLLECTIVE BEFORE TOUCHDOWN DID NOT ARREST THE DESCENT RATE.
Flight
Event TypeAccident
Event Time08:55 CST
Nearest AirportArlington Municipal (0nm)
Runway16
Runway Length4000 ft
Runway Width100 ft
Flight Plan FiledNone
Aircraft FireNo
Aircraft ExplosionNo
Aircraft
AircraftBell 206L-3+
Tail NumberN2770X
Aircraft CategoryHeli
DamageSubstantial
OperatorBell Helicopter Textron
Operating RulePart 91
Engines1
Engine TypeTurboshaft
Engine DetailsAllison · 250C-30P · Turboshaft · 650
Seats2
People & Injuries
Injury SummaryNo injuries (2 uninjured)
Fatal0
Serious0
Minor0
Uninjured2
Total2
Crew 1Age 53 · Second Class
Conditions
ConditionsVMC
LightDaylight
WindCalm
Visibility12 sm
CeilingNone
Temperature / Dew Point52 / 46
Altimeter30.00 inHg
Observation Time14:50
Weather SourceWFAC