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NTSB Report
December 20, 1986 · Swearingen SA226TC · N124AV
Billings, MT
Overview
Report Status
Preliminary report
Event Type
Incident
Date
December 20, 1986
Injury Outcomes
No injuries (13 uninjured)
Location
Billings, MT
Aircraft
Swearingen SA226TC
Tail Number
N124AV
Operator
Big Sky Airlines
Injuries
None
Aircraft Damage
Minor
NTSB Number
DEN87IA032
N124AV WAS OPERATING AS BIG SKY AIRLINES FLT 3857, SCHEDULED SERVICE FROM HELENA TO BILLINGS. THE FLT PROCEEDED UNEVENTFULLY UNTIL THE APCH INTO BILLINGS. THE FLT CREW STATED AFTER THE INCIDENT THAT WHEN THE LANDING GEAR WAS EXTENDED, THE LEFT MAIN GEAR LIGHTS DID NOT ILLUMINATE, VERIFYING THE 'DOWN AND LOCKED POSITION..' AFTER NUMEROUS ATTEMPTS TO ILLUMINATE THE LIGHTS AND CONFIRM THE POSITION OF THE LANDING GEAR, THE CREW EXECUTED AN INTENTIONAL GEAR UP LANDING. POST INCIDENT INSPECTION OF THE LANDING GEAR SYSTEM REVEALED IT WAS CAPABLE OF NORMAL OPERATION. THE MALFUNCTIONING COCKPIT INDICATOR LIGHT WAS TRACED BACK TO AN INOPERATIVE OUTBOARD DOWNLOCK MICROSWITCH.
Full Narrative
N124AV WAS OPERATING AS BIG SKY AIRLINES FLT 3857, SCHEDULED SERVICE FROM HELENA TO BILLINGS. THE FLT PROCEEDED UNEVENTFULLY UNTIL THE APCH INTO BILLINGS. THE FLT CREW STATED AFTER THE INCIDENT THAT WHEN THE LANDING GEAR WAS EXTENDED, THE LEFT MAIN GEAR LIGHTS DID NOT ILLUMINATE, VERIFYING THE 'DOWN AND LOCKED POSITION..' AFTER NUMEROUS ATTEMPTS TO ILLUMINATE THE LIGHTS AND CONFIRM THE POSITION OF THE LANDING GEAR, THE CREW EXECUTED AN INTENTIONAL GEAR UP LANDING. POST INCIDENT INSPECTION OF THE LANDING GEAR SYSTEM REVEALED IT WAS CAPABLE OF NORMAL OPERATION. THE MALFUNCTIONING COCKPIT INDICATOR LIGHT WAS TRACED BACK TO AN INOPERATIVE OUTBOARD DOWNLOCK MICROSWITCH.
Flight
Event TypeIncident
Event Time21:10 MST
Nearest AirportBillings Logan Int'L. (0nm N)
Runway27R
Runway Length10500 ft
Runway Width150 ft
Flight Plan FiledIFR
Aircraft FireNo
Aircraft ExplosionNo
Aircraft
AircraftSwearingen SA226TC
Tail NumberN124AV
Aircraft CategoryAir
DamageMinor
OperatorBig Sky Airlines
Operating RulePart 135
Engines2
Engine TypeTurboprop
Engine DetailsGarrett · TPE331-3U303G · Turboprop · 904
Seats15
People & Injuries
Injury SummaryNo injuries (13 uninjured)
Fatal0
Serious0
Minor0
Uninjured13
Total13
Crew 1Age 45 · First Class
Conditions
ConditionsVMC
LightDark Night
Wind230° @ 11 kt
Visibility20 sm
CeilingOvercast 20000 ft
Temperature / Dew Point30 C / 10 C
Altimeter30.00 inHg
Observation Time04:17
Weather SourceWFAC