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CHI92FA020

1991-10-31 · ZION, Illinois, United States · Serious · 1 aircraft · Status: Completed

Airport UGN

Aircraft involved

Probable cause & findings

WATER CONTAMINATION OF THE FUEL, AND THE PILOT'S INADEQUATE PREFLIGHT OF THE AIRCRAFT. FACTORS RELATED TO THE ACCIDENT WERE: DARKNESS AND OBSTRUCTIONS (TREES & TRANSMISSION LINES) IN THE EMERGENCY LANDING AREA.

Factual narrative

THE SINGLE ENGINED AIRPLANE WAS OPERATING ON AN IFR FLIGHT PLAN AND CLIMBING THROUGH CLOUDS SHORTLY AFTER TAKEOFF. A WITNESS HEARD AN AIRPLANE'S ENGINE POWER SURGING AND OBSERVED A BRIGHT FLASH AT GROUND LEVEL SHORTLY AFTERWARDS. ANOTHER WITNESS OBSERVED THE AIRPLANE DESCENDING AND FLY PAST HIM JUST BEFORE SEEING A BRIGHT FLASH AND HEARING THE CRASH. THE AIRPLANE STRUCK AN ELECTRICAL POWERLINE AND TREE BEFORE COLLIDING WITH THE GROUND AND SLIDING TO A STOP. AN ON-SCENE INVESTIGATION REVEALED WATER IN THE CARBURETOR FLOAT AND ACCELERATOR PUMP CHAMBERS. THE COMMUTATOR OF THE TURN AND SLIP INDICATOR'S ELECTRIC MOTOR WAS FOUND WITH A GROOVE WORN AROUND IT AND A BLACK POWDERY SUBSTANCE PERMEATING THE INTERNAL MECHANISM OF THE INSTRUMENT. DURING AN INTERVIEW WITH THE PILOT, HE STATED THAT HE HAD TAKEN A FUEL SAMPLE FROM EACH FUEL SUMP ON THE AIRPLANE DURING HIS PRE-FLIGHT WALK AROUND INSPECTION. THE PILOT WAS UNABLE TO RECALL THE EVENTS WHICH TOOK PLACE AFTER ENTERING THE CLOUDS. Source: NTSB Aviation Accident Database (Pre-2008 Archive) Retrieved: 2026-02-12

Verbatim from NTSB's published report. Source file NTSB_1991_CHI92FA020.txt. Findings + structured fields enriched from FAA avall.mdb. Full investigation docket on data.ntsb.gov ↗.

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