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Aviation safety reports, made easier to study

NTSB Reports is an independent research and search tool for public aviation accident and incident records. It brings NTSB aviation reports, structured fields, docket files, extracted figures, photos, videos, and update history into one searchable interface.

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April 20, 1990 · Beech F33A · N179DD

Milwaukee, WI

Overview

Report Status
Probable Cause
Event Type
Accident
Date
April 20, 1990
Injury Outcomes
3 injuries (3 minor injuries)
Location
Milwaukee, WI
Aircraft
Beech F33A
Tail Number
N179DD
Operator
Delta Delta Partnership
Injuries
Minor
Aircraft Damage
Substantial
NTSB Number
CHI90LA115

THE PILOT ENGAGED THE AUTOPILOT APPROACH MODE TO EXECUTE A COUPLED ILS APPROACH WHILE HE WAS HIGH AND FAST WITH A 2000 FOOT PER MINUTE RATE OF DESCENT. THIS WAS OUTSIDE THE PARAMETERS FOR A STABILIZED APPROACH. WHEN THE AUTOPILOT CAPTURED THE GLIDE SLOPE, THE AIRCRAFT NOSED OVER SHARPLY, FLEW THROUGH THE GLIDE SLOPE, PULLED UP SHARPLY, FLEW THROUGH THE GLIDE SLOPE GOING UP, AND NOSED OVER AGAIN BEFORE THE PILOT COULD DISENGAGE THE AUTOPILOT. PILOT LANDED THE AIRCRAFT WITHOUT FURTHER INCIDENT, BUT THE PITCH EXCURSIONS HAD EXCEEDED THE STRESS LIMITS OF THE AIRCRAFT.

NTSB Probable Cause

THE UTILIZATION OF IMPROPER PROCEDURES ON THE PART OF THE PILOT IN COMMAND BY ATTEMPTING TO EXECUTE A COUPLED APPROACH OUTSIDE THE PARAMETERS OF THE AUTOPILOT.

Full Narrative

THE PILOT ENGAGED THE AUTOPILOT APPROACH MODE TO EXECUTE A COUPLED ILS APPROACH WHILE HE WAS HIGH AND FAST WITH A 2000 FOOT PER MINUTE RATE OF DESCENT. THIS WAS OUTSIDE THE PARAMETERS FOR A STABILIZED APPROACH. WHEN THE AUTOPILOT CAPTURED THE GLIDE SLOPE, THE AIRCRAFT NOSED OVER SHARPLY, FLEW THROUGH THE GLIDE SLOPE, PULLED UP SHARPLY, FLEW THROUGH THE GLIDE SLOPE GOING UP, AND NOSED OVER AGAIN BEFORE THE PILOT COULD DISENGAGE THE AUTOPILOT. PILOT LANDED THE AIRCRAFT WITHOUT FURTHER INCIDENT, BUT THE PITCH EXCURSIONS HAD EXCEEDED THE STRESS LIMITS OF THE AIRCRAFT.

Flight

Event TypeAccident
Event Time16:00 CDT
Nearest AirportMilwaukee Mitchell (0nm N)
Runway0
Flight Plan FiledIFR
Aircraft FireNo
Aircraft ExplosionNo

Aircraft

AircraftBeech F33A
Tail NumberN179DD
Aircraft CategoryAir
DamageSubstantial
OperatorDelta Delta Partnership
Operating RulePart 91
Engines1
Engine TypeReciprocating
Engine DetailsContinental · IO-520-BA · Reciprocating · 285
Seats5

People & Injuries

Injury Summary3 injuries (3 minor injuries)
Fatal0
Serious0
Minor3
Uninjured0
Total3
Crew 1Age 47 · Third Class

Conditions

ConditionsVMC
LightDaylight
Wind300° @ 5 kt
Visibility5 sm
CeilingOvercast 1000 ft
Temperature / Dew Point59 / 54
Altimeter30.00 inHg
Observation Time20:51
Weather SourceWFAC

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Appendix: Source Data