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NTSB Report
October 11, 1991 · Beech K35 · N9559R
Grass Valley, CA
Overview
Report Status
Probable Cause
Event Type
Accident
Date
October 11, 1991
Injury Outcomes
No injuries (3 uninjured)
Location
Grass Valley, CA
Aircraft
Beech K35
Tail Number
N9559R
Operator
Mike Collishaw
Injuries
None
Aircraft Damage
Substantial
NTSB Number
LAX92LA012
IN AN ORAL STATEMENT, THE PILOT SAID THAT AS HE APPROACHED THE AIRPORT HE OBSERVED SQUALL LINE ACTIVITY AND DECIDED TO ORBIT UNTIL THE WEATHER CLEARED. AFTER THE WEATHER CONDITIONS VISUALLY IMPROVED, THE PILOT ENTERED THE PATTERN FOR LANDING. HE STATED THAT ON SHORT FINAL APPROACH THE AIRCRAFT ENCOUNTERED SEVERE TURBULENCE AND A DOWN DRAFT. THE PILOT INITIATED A GO AROUND, HOWEVER, THE AIRCRAFT ROLLED VIOLENTLY AND THE WING TIP STRUCK THE GROUND. AN AIRPORT ATTENDANT STATED THAT HE WAS IN THE OFFICE WHERE THE WEATHER OBSERVATION INSTRUMENTS ARE LOCATED AT THE TIME OF THE ACCIDENT. HE SAID THAT THE WINDS WERE 30 TO 40 KNOTS WITH SUDDEN 180 DEGREE CHANGES IN DIRECTION AT THE TIME THE PILOT ATTEMPTED HIS APPROACH. THUNDERSTORM CLOUDS WERE VISIBLE IN THE DISTANCE AND THE AIRPORT WAS EXPERIENCING INTERMITTENT HEAVY RAIN SHOWERS.
NTSB Probable Cause
THE INADVERTENT ENCOUNTER WITH A MICROBURST/DOWNBURST PHENOMENA ASSOCIATED WITH THUNDERSTORM ACTIVITY. A FACTOR IN THE ACCIDENT WAS THE FAILURE OF THE PILOT TO ADEQUATELY ASSESS THE WEATHER CONDITIONS DURING THE LANDING ATTEMPT.
Full Narrative
IN AN ORAL STATEMENT, THE PILOT SAID THAT AS HE APPROACHED THE AIRPORT HE OBSERVED SQUALL LINE ACTIVITY AND DECIDED TO ORBIT UNTIL THE WEATHER CLEARED. AFTER THE WEATHER CONDITIONS VISUALLY IMPROVED, THE PILOT ENTERED THE PATTERN FOR LANDING. HE STATED THAT ON SHORT FINAL APPROACH THE AIRCRAFT ENCOUNTERED SEVERE TURBULENCE AND A DOWN DRAFT. THE PILOT INITIATED A GO AROUND, HOWEVER, THE AIRCRAFT ROLLED VIOLENTLY AND THE WING TIP STRUCK THE GROUND. AN AIRPORT ATTENDANT STATED THAT HE WAS IN THE OFFICE WHERE THE WEATHER OBSERVATION INSTRUMENTS ARE LOCATED AT THE TIME OF THE ACCIDENT. HE SAID THAT THE WINDS WERE 30 TO 40 KNOTS WITH SUDDEN 180 DEGREE CHANGES IN DIRECTION AT THE TIME THE PILOT ATTEMPTED HIS APPROACH. THUNDERSTORM CLOUDS WERE VISIBLE IN THE DISTANCE AND THE AIRPORT WAS EXPERIENCING INTERMITTENT HEAVY RAIN SHOWERS.
Flight
Event TypeAccident
Event Time16:00 PDT
Nearest AirportNevada County (0nm)
Runway7
Runway Length3920 ft
Runway Width50 ft
Flight Plan FiledNone
Aircraft FireNo
Aircraft ExplosionNo
Aircraft
AircraftBeech K35
Tail NumberN9559R
Aircraft CategoryAir
DamageSubstantial
OperatorMike Collishaw
Operating RulePart 91
Engines1
Engine TypeReciprocating
Engine DetailsContinental · IO-470C · Reciprocating · 250
Seats4
People & Injuries
Injury SummaryNo injuries (3 uninjured)
Fatal0
Serious0
Minor0
Uninjured3
Total3
Crew 1Age 32 · Second Class
Conditions
ConditionsVMC
LightDaylight
Wind15 kt, gusting 40 kt
Visibility50 sm
CeilingOvercast 4000 ft
Temperature / Dew Point0 C / 0 C
Altimeter0
Weather SourcePILO