# NTSB CHI90LA115: Beech F33A, N179DD, Milwaukee, WI, April 20, 1990

- Type: NTSB accident investigation
- Classification: Accident · Minor injuries · Limited investigation · Final report
- Date: April 20, 1990, 16:00 local (21:00 UTC)
- Place: Milwaukee, WI
- Coordinates: 42.980438, -87.89933 (estimated)
- Nearby events: https://openairdocs.org/map.md?lat=42.9804&lon=-87.8993&mi=10
- Phase of flight: [Approach](https://openairdocs.org/ntsb-phases/500) (OpenAirDocs' grouping)
- Highest injury: Minor injuries
- Injuries: 3 minor
- Status: Completed, report October 2, 1992
- Report: Approved by Office Director
- NTSB case key (mKey): 14658
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=CHI90LA115
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/14658/pdf
- Page: https://openairdocs.org/ntsb/CHI90LA115

## 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.

## Sequence of events

In NTSB's coding before 2008 (https://www.ntsb.gov/GILS/Documents/codman.pdf).

- Abrupt maneuver, approach - iaf to faf/outer marker (ifr)
  - proper descent rate - exceeded, pilot in command
  - procedures/directives - not followed, pilot in command (cause)
  - design stress limits of aircraft - exceeded

## Analysis

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.

## Aircraft

- Registration: [N179DD](https://openairdocs.org/deregistered/N179DD-2013-08-05), registration cancelled 2013-08-05, S/N CE-743, built 1977 (OpenAirDocs)
- Reported make and model: Beech F33A
- Registry model: [Beech F33A](https://openairdocs.org/model/beech-f33a) (registry code 1151425) (OpenAirDocs)
- Registry engine: [Continental IO-520 series](https://openairdocs.org/engine/continental-io-520-series) (registry code 17032, reciprocating) (OpenAirDocs)
- Category: Airplane
- Serial number: CE743
- Airframe hours: 3886
- Engines: CONTINENTAL IO-520-BA 285 horsepower reciprocating
- Damage: Substantial damage
- Flight: Business, Part 91
- Operator: Delta Delta Partnership
- Registered owner: Delta Delta Partnership
- Airworthiness certificate: Standard, Normal; Standard, Utility
- Last inspection: Annual, June 1, 1989, 275 hours before
- Departed: FAR, FARGO, ND
- Flight plan: IFR
- Airport: MKE, Milwaukee Mitchell

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 47; private; airplane ratings: single-engine land; instrument ratings: airplane; medical: class 3, valid medical--no waivers/lim.; seat: left; flight hours: 2,003 total, 888 in this make and model, 1,915 as pilot in command, 52 in the last 90 days, 24 in the last 30 days, 3 in the last 24 hours

## Weather

- Conditions: Visual (VMC), Day
- Wind: 300° at 5 knots
- Visibility: 5 statute miles
- Lowest ceiling: 1,000 ft overcast
- Temperature: 59 °F, dew point 54 °F
- Altimeter: 30.00 inHg
- Observed at: MKE, 4 nm away

## FAA reports on this event (1)

The FAA's own accident and incident reports, matched to the aircraft by N-number and date (OpenAirDocs).

- [Accident 19900420010469A](https://openairdocs.org/incident/19900420010469A), Apr 20, 1990: Beech F33A, Milwaukee, WI, Substantial damage. High on coupled approach. Letdown at 2000 fpm. Auto pilot overcontrolled intercepting glide path. Airframe damaged.

## Other investigations on N179DD (1)

From the NTSB's public API. Aircraft are matched to registry aircraft by N-number and event date, checked against the reported serial number, make and model; the registry's history has gaps, so older matches can be wrong. Compare the reported make and model.

- [NTSB FTW97LA297](https://openairdocs.org/ntsb/FTW97LA297), Aug 3, 1997: Beech F33A (N179DD), Creede, CO, destroyed. Probable cause: The pilot's intentional low altitude flight over mountainous terrain, inadequate altitude to clear surrounding obstacles, and his misjudging vertical clearance. A factor was the pilot's use of an…

From the NTSB's public API. Aircraft are matched to registry aircraft by N-number and event date, checked against the reported serial number, make and model; the registry's history has gaps, so older matches can be wrong. Compare the reported make and model.

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