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CHI91FA254

1991-08-06 · OTTUMWA, Iowa, United States · Fatal · 1 aircraft · Status: Completed

Airport OTM

Aircraft involved

Probable cause & findings

IMPROPER IFR PROCEDURE BY THE PILOT BY NOT MAINTAINING THE PROPER MINIMUM DESCENT ALTITUDE (MDA) UNTIL ESTABLISHED ON THE ILS LOCALIZER AND GLIDEPATH.

Factual narrative

DURING ARRIVAL, THE PILOT WAS CLEARED FOR AN ILS RUNWAY 31 APPROACH. AS HE CONTINUED THE APPROACH, THE AIRPLANE DESCENDED INTO TREES AND THE TERRAIN, INSIDE THE OUTER MARKER, 4.0 MILES FROM THE THRESHOLD AND .19 MILE TO THE LEFT OF CENTERLINE. INITIAL IMPACT WAS ON A HEADING OF 356 DEGREES MAGNETIC AT AN ELEVATION OF 820 FEET MSL. THE AIRPORT ELEVATION WAS 845 FEET MSL. MINIMUM DESCENT ALTITUDE (MDA) BEFORE REACHING THE ILS GLIDE SLOPE WAS 2800 FEET; MDA FOR A LOCALIZER ONLY APPROACH WAS 1200 FEET. DECISION HEIGHT (IF ESTABLISHED ON THE ILS LOCALIZER & GLIDEPATH) WAS 1041 FEET. SUBSEQUENT INVESTIGATION FAILED TO REVEAL ANY MECHANICAL MALFUNCTION OF THE AIRCRAFT OR SIGNIFICANT WEATHER PHENOMENA WHICH WOULD HAVE RESULTED IN THE ACCIDENT. Source: NTSB Aviation Accident Database (Pre-2008 Archive) Retrieved: 2026-02-12

Verbatim from NTSB's published report. Source file NTSB_1991_CHI91FA254.txt. Findings + structured fields enriched from FAA avall.mdb. Full investigation docket on data.ntsb.gov ↗.

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