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NTSB Report
December 28, 1983 · Lake LA-4-200 · N39451
Great Falls, MT
Overview
Report Status
Preliminary report
Event Type
Accident
Date
December 28, 1983
Injury Outcomes
No injuries (1 uninjured)
Location
Great Falls, MT
Aircraft
Lake LA-4-200
Tail Number
N39451
Injuries
None
Aircraft Damage
Substantial
NTSB Number
DEN84LA052
THE ACFT WAS DAMAGED IN A FORCED LANDING ON A HIGHWAY AFTER THE ENGINE SEIZED. THE PLT SAID 'THE ENGINE MADE UNUSUAL SOUNDS OF AN ENGINE RUNNING BAD.' THEN IT LOST COMPRESSION AND SEIZED. HE MADE A FORCED LANDING ON A HIGHWAY AND DAMAGEDTHE HULL. EXAMINATION OF THE ACFT REVEALED A SITUATION WHERE THE MAIN OIL BREATHER FROZE PREVENTING OIL VAPOR PRESSURE FROM VENTING; CAUSING THE ENGINE SEALS TO FAIL AND THEREBY DEPLETNG THE OIL SUPPLY.
Full Narrative
THE ACFT WAS DAMAGED IN A FORCED LANDING ON A HIGHWAY AFTER THE ENGINE SEIZED. THE PLT SAID 'THE ENGINE MADE UNUSUAL SOUNDS OF AN ENGINE RUNNING BAD.' THEN IT LOST COMPRESSION AND SEIZED. HE MADE A FORCED LANDING ON A HIGHWAY AND DAMAGEDTHE HULL. EXAMINATION OF THE ACFT REVEALED A SITUATION WHERE THE MAIN OIL BREATHER FROZE PREVENTING OIL VAPOR PRESSURE FROM VENTING; CAUSING THE ENGINE SEALS TO FAIL AND THEREBY DEPLETNG THE OIL SUPPLY.
Flight
Event TypeAccident
Event Time22:10 MST
Nearest AirportGreat Falls (1nm E)
Runway0
Flight Plan FiledNone
Aircraft FireNo
Aircraft ExplosionNo
Aircraft
AircraftLake LA-4-200
Tail NumberN39451
Aircraft CategoryAir
DamageSubstantial
Operating RulePart 91
Engines1
Engine TypeReciprocating
Engine DetailsLycoming · IO-360-A1B · Reciprocating · 180
Seats4
People & Injuries
Injury SummaryNo injuries (1 uninjured)
Fatal0
Serious0
Minor0
Uninjured1
Total1
Crew 1Age 36 · Second Class
Conditions
ConditionsVMC
LightDark Night
Wind220° @ 13 kt
Visibility15 sm
CeilingNone
Temperature / Dew Point-9 C / 16 C
Altimeter30.00 inHg
Observation Time05:23
Weather SourceWFAC