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NTSB Report
August 26, 1990 · Bell 47G-2 · N90529
Wall Lake, IA
Overview
Report Status
Probable Cause
Event Type
Accident
Date
August 26, 1990
Injury Outcomes
No injuries (1 uninjured)
Location
Wall Lake, IA
Aircraft
Bell 47G-2
Tail Number
N90529
Injuries
None
Aircraft Damage
Substantial
NTSB Number
CHI90DCD02
AFTER REFUELING & RELOADING THE HELICOPTER WITH A SPRAY SOLUTION AT A FIELD SITE, A TAKEOFF WAS INITIATED IN CALM WIND CONDITIONS. THE PLT RPRTD THAT THE LOCATION REQUIRED HIM TO TAKE OFF UPSLOPE. HE STATED THAT THE RPM DROPPED SLIGHTLY, BUT REMAINED IN THE GREEN ARC DURING THE UPSLOPE PORTION OF THE TAKEOFF. AS THE HELICOPTER CROSSED A FENCE & THE TERRAIN STARTED SLOPING DOWNHILL, THE HELICOPTER FLEW OUT OF GROUND EFFECT. THE PLT RPRTD HE LEVELED THE HELICOPTER, THEN BEGAN A SLIGHT DSCNT TO INCREASE RPM & AIRSPEED. HOWEVER, THE ROTOR RPM DECAYED & JUST BEFORE TOUCHDOWN, THE HELICOPTER YAWED 90 DEG TO THE RIGHT. AFTER TOUCHDOWN, THE HELICOPTER ROLLED OVER. DENSITY ALT WAS ESTD TO BE 3216 FT.
NTSB Probable Cause
THE FAILURE OF THE PILOT TO MAINTAIN ROTOR RPM DURING TAKEOFF. THE HIGH DENSITY ALTITUDE AND UPHILL TERRAIN WERE FACTORS.
Full Narrative
AFTER REFUELING & RELOADING THE HELICOPTER WITH A SPRAY SOLUTION AT A FIELD SITE, A TAKEOFF WAS INITIATED IN CALM WIND CONDITIONS. THE PLT RPRTD THAT THE LOCATION REQUIRED HIM TO TAKE OFF UPSLOPE. HE STATED THAT THE RPM DROPPED SLIGHTLY, BUT REMAINED IN THE GREEN ARC DURING THE UPSLOPE PORTION OF THE TAKEOFF. AS THE HELICOPTER CROSSED A FENCE & THE TERRAIN STARTED SLOPING DOWNHILL, THE HELICOPTER FLEW OUT OF GROUND EFFECT. THE PLT RPRTD HE LEVELED THE HELICOPTER, THEN BEGAN A SLIGHT DSCNT TO INCREASE RPM & AIRSPEED. HOWEVER, THE ROTOR RPM DECAYED & JUST BEFORE TOUCHDOWN, THE HELICOPTER YAWED 90 DEG TO THE RIGHT. AFTER TOUCHDOWN, THE HELICOPTER ROLLED OVER. DENSITY ALT WAS ESTD TO BE 3216 FT.
Flight
Event TypeAccident
Event Time19:40 CDT
Nearest Airport0nm N
Runway0
Runway Length0
Runway Width0
Flight Plan FiledNone
Aircraft FireNo
Aircraft ExplosionNo
Aircraft
AircraftBell 47G-2
Tail NumberN90529
Aircraft CategoryHeli
DamageSubstantial
Operating RulePart 137
Engines1
Engine TypeReciprocating
Engine DetailsLycoming · VO-435-A1F · Reciprocating · 270
Seats1
People & Injuries
Injury SummaryNo injuries (1 uninjured)
Fatal0
Serious0
Minor0
Uninjured1
Total1
Crew 1Age 44 · Second Class
Conditions
ConditionsVMC
LightDaylight
WindCalm
Visibility1 sm
CeilingNone
Altimeter29.00 inHg
Observation Time00:53
Weather SourcePILO