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Atlas / NTSB / CHI90DEP07

NTSB CAROL · Event

Event CHI90DEP07

1990-07-09 HATLEY, Wisconsin, United States None 1 aircraft Status: Completed

Aircraft involved

Probable cause & findings

THE PARTIAL LOSS OF POWER DUE TO STICKING INTAKE VALVES.

Factual narrative

THE HELICOPTER WAS LOADED WITH CHEMICALS FOR AGRICULTURE DISPERSAL ON A TRUCK MOUNTED PLATFORM, TEN FEET ABOVE GROUND LEVEL. ON LIFTOFF THE ENGINE SUSTAINED A PARTIAL POWER REDUCTION DUE TO TWO STICKING INTAKE VALVES. THE AIRCRAFT DESCENDED INTO THE TERRAIN WHEN ALTITUDE PROVED INSUFFICIENT TO EFFECT AN AUTOROTATIONAL FORCED LANDING. Source: NTSB Aviation Accident Database (Pre-2008 Archive) Retrieved: 2026-02-12

Verbatim from NTSB's published report. Source file NTSB_1990_CHI90DEP07.txt. Findings + structured fields enriched from FAA avall.mdb. Full investigation docket on data.ntsb.gov ↗.