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ANC90LA068 · Artic Aircraft Corp. INTERSTATE S1B1 INTERSTATE

13 May 1990 · Talkeetna, AK, United States

Artic Aircraft Corp. INTERSTATE S1B1 INTERSTATE · Accident: partial loss of engine power (non-mechanical) en route

From Z70 · CANTWELL, AK to an unrecorded destination

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Event

NTSB case
ANC90LA068
Event typeAccident: someone killed or seriously injured, or the aircraft substantially damaged (NTSB definition). Incident: an occurrence that affected or could have affected safety, short of that. Glossary
Accident
InvestigationHow far the investigation had got when the record was published: preliminary, ongoing, final or completed. Unknown where the source does not say. Glossary
Completed
API-reported fatalities
0 · all aircraft and ground
Ground fatalities
0
OperationWhat kind of flying it was, grouped by the rules it flew under: airline (US Part 121), air taxi and commuter (Part 135), general aviation (Part 91 and similar), military or government. Glossary
General aviation
WeatherVisual meteorological conditions (VMC): good enough to fly by looking outside. Instrument conditions (IMC): cloud or low visibility, flying by instruments. Glossary
Visual Meteorological Cond

Artic Aircraft Corp. INTERSTATE S1B1 INTERSTATE

Category
Airplane
RegistrationThe aircraft's tail number, such as N12345 or G-ABCD. Registrations are reissued, so the same one years apart can be a different aircraft. Glossary
N73AR
Operator
Unknown
Onboard fatalities
Unknown
Route
From Z70 · CANTWELL, AKTo not recorded
Aircraft age
Not recorded
Flight rulesThe regulations the flight operated under: in the US, Part 91 (general aviation), Part 121 (airlines), Part 135 (air taxi and commuter) and others; for flights abroad, the NTSB's coarser commercial or non-commercial code. Glossary
Part 91: General Aviation
Phase of flightThe stage of the flight when things started to go wrong: standing, taxi, takeoff, initial climb, en route, maneuvering, approach or landing. Glossary
En route · climb to cruise
First occurrenceThe single coded event the NTSB judges best describes what happened (records from 2008 on). Older records name the first occurrence in the sequence instead. Glossary
Partial loss of engine power (non-mechanical)
Also codedOther events the NTSB coded in the sequence, such as a wire strike after a loss of power. Flight Findings uses them for its kinds of event. Glossary
Fuel contamination
DamageDestroyed: beyond practical repair. Substantial: damage that affects the structure, performance or handling and normally needs major repair. Minor: less than that. Glossary
Substantial

Cause areas

  • Fluid, fuel › Contamination

Approximate · Coordinates as recorded by the NTSB; no uncertainty radius is established.

NTSB narrative

THE PILOT-IN-COMMAND ADDED FULL POWER AND ATTEMPTED TO CLIMB OVER A RIDGE WHEN THE ENGINE BEGAN TO SPUTTER. HE WAS FORCED TO LAND ON UNIMPROVED TERRAIN. EXAMINATION OF THE FUEL IN THE AIRPLANE REVEALED BROWN FLAKES WHICH WERE EXAMINED AND FOUND TO BE FLAKES OF GASOLINE VARNISH. THE PILOT STATED THE AIRPLANE HAD SAT WITHOUT OPERATING FOR A LONG TIME PRIOR TO HIS PURCHASE OF THE AIRPLANE.

Probable cause

FUEL CONTAMINATION WHICH PRECLUDED THE ENGINE FROM DEVELOPING THE NECESSARY POWER TO CLEAR THE MOUNTAIN RIDGE.

Verbatim NTSB analysis and probable cause from the NTSB dataset

Sources

NTSB record ANC90LA068
Event ID
20001212X23044
Case number
ANC90LA068
Dataset
historical-pre2008
Source SHA-256
89e2df6d848e7ab3b42e7d7c7a03ff403303057a26ca04c95b3ea67201c3ce74
Source notes (4)
  • Unreviewed is an editorial label, not an investigation status. API-sourced is not report-checked or human-reviewed. Explicit event totals are used without summing aircraft injury tables; onboard allocation is withheld. Unknown values remain unknown. The operation category is mapped from the NTSB-reported FAR part and has not been reviewed.
  • Filled from the NTSB case API where the bulk record had no value: local date, investigation status. Values present in the bulk record are kept.
  • The date is the local date; the NTSB stores the UTC date 1990-05-14.
  • API snapshot SHA-256: 35d4ac95c8285be6ef8297baf603e5ebb2d0e1460f3f979d07c45083cd36e882; retrieved 2026-09-23T06:16:46.556Z.