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NTSB Report
November 16, 1990 · Air Tractor AT-302 · N4441S
Somerton, AZ
Overview
Report Status
Probable Cause
Event Type
Accident
Date
November 16, 1990
Injury Outcomes
No injuries (1 uninjured)
Location
Somerton, AZ
Aircraft
Air Tractor AT-302
Tail Number
N4441S
Operator
Kottenbrook Jeffrey L
Injuries
None
Aircraft Damage
Substantial
NTSB Number
LAX91DUJ03
THE PILOT EXPERIENCED A LOSS OF ENGINE POWER AND COLLIDED WITH THE TERRAIN DURING A SWATH RUN. EXAMINATION OF THE ENGINE REVEALED THE NUMBER 3 EXHAUST VALVE WAS CRACKED. THE ENGINE HAD 266 HOURS SINCE OVERHAUL AND HAD 20 HOURS SINCE THE LAST INSPECTION.
NTSB Probable Cause
THE FAILURE OF THE NUMBER 3 EXHAUST VALVE WHICH LED TO AN ENGINE FAILURE AND SUBSEQUENT CRASH LANDING.
Full Narrative
THE PILOT EXPERIENCED A LOSS OF ENGINE POWER AND COLLIDED WITH THE TERRAIN DURING A SWATH RUN. EXAMINATION OF THE ENGINE REVEALED THE NUMBER 3 EXHAUST VALVE WAS CRACKED. THE ENGINE HAD 266 HOURS SINCE OVERHAUL AND HAD 20 HOURS SINCE THE LAST INSPECTION.
Flight
Event TypeAccident
Event Time20:30 MST
Nearest Airport0nm N
Runway0
Runway Length0
Runway Width0
Flight Plan FiledNone
Aircraft FireGrd
Aircraft ExplosionNo
Aircraft
AircraftAir Tractor AT-302
Tail NumberN4441S
Aircraft CategoryAir
DamageSubstantial
OperatorKottenbrook Jeffrey L
Operating RulePart 137
Engines1
Engine TypeReciprocating
Engine DetailsP&W · R-1340 AN1 · Reciprocating · 600
Seats1
People & Injuries
Injury SummaryNo injuries (1 uninjured)
Fatal0
Serious0
Minor0
Uninjured1
Total1
Crew 1Age 47 · Second Class
Conditions
ConditionsVMC
LightDark Night
WindCalm
CeilingNone
Temperature / Dew Point70 F / 30 C
Altimeter30.00 inHg
Weather SourcePILO