# NTSB CHI93DEP02: Stoeckler RV-4, N720DS, Lake Delton, WI, July 24, 1993

- Type: NTSB accident investigation
- Classification: Accident · Fatal · Final report
- Date: July 24, 1993, 14:20 local (19:20 UTC)
- Place: Lake Delton, WI
- Location: 43.5920° N, 89.7831° W: Placed by OpenAirDocs: center of Lake Delton, WI, within about 6 miles (OpenAirDocs)
- Nearby events: https://openairdocs.org/map.md?lat=43.5920&lon=-89.7831&mi=10
- Phase of flight: [Maneuvering](https://openairdocs.org/ntsb-phases/450) (OpenAirDocs' grouping)
- Highest injury: Fatal
- Injuries: 1 fatal, 1 serious
- Status: Completed, report August 17, 1994
- Report: Approved by Office Director
- NTSB case key (mKey): 9143
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=CHI93DEP02
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/9143/pdf
- Page: https://openairdocs.org/ntsb/CHI93DEP02

## Probable cause

the pilot-in-command's failure to maintain proper altitude.  A factor was trees.

## Sequence of events

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

- In flight collision with object, maneuvering
  - object - tree(s) (contributing factor)
  - proper altitude - not maintained, pilot in command (cause)
- In flight collision with terrain/water, descent - uncontrolled

## Analysis

WITNESSES OBSERVED THE AIRPLANE MANEUVERING NEAR A RESIDENTIAL AREA, MAKING 30 TO 45 DEGREE BANKED LEFT TURNS.  ON THE LAST CIRCLE THE AIRPLANE COLLIDED WITH TREE TOPS, LEVELED MOMENTARILY AND THEN NOSED OVER AND IMPACTED THE TERRAIN.

## Factual narrative

HISTORY OF FLIGHT

On July 24, 1993, at approximately 1420 Central Daylight Time, a homebuilt Stoeckler RV-4, N720DS, registered to Danny R. Stoeckler, was destroyed when it struck trees while circling over a residential area in Lake Delton, Wisconsin.  The private pilot incurred fatal injuries, and the passenger received serious injuries.  The 14 CFR Part 91 flight originated from Milwaukee, Wisconsin, and was operating in visual meteorological conditions with no flight plan on file.

Witnesses observed the aircraft circling the area 3 to 4 times in a 30 to 45 degree bank, descending left turn.  On the last circle, witnesses indicated the aircraft made a steep left turn, collided with the top of the trees, leveled momentarily in a nose high attitude, and then nosed over and crashed almost vertically into the ground.  The witnesses also reported that the engine was running normally at the time of impact.

## Aircraft

- Registration: [N720DS](https://openairdocs.org/deregistered/N720DS-1997-05-21), registration cancelled 1997-05-21, S/N 1083 (OpenAirDocs)
- Reported make and model: STOECKLER RV-4
- Registry model: [Stoeckler Danny Robert RV-4](https://openairdocs.org/model/stoeckler-danny-robert-rv-4) (registry code 056086U) (OpenAirDocs)
- Category: Airplane, amateur-built
- Serial number: 1083
- Engines: LYCOMING O-320 150 horsepower reciprocating
- Damage: Destroyed
- Flight: Personal, Part 91
- Registered owner: Stoeckler, Danny R.
- Airworthiness certificate: Special, Experimental (Special)
- Departed: O2C, BROOKFIELD, WI

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 33; private; airplane ratings: single-engine land; medical: class 3, expired; seat: front; toxicology performed

## Weather

- Conditions: Visual (VMC), Day
- Wind: 180° at 8 knots
- Visibility: 10 statute miles
- Lowest ceiling: 8,000 ft broken
- Temperature: 84 °F, dew point 72 °F
- Altimeter: 29.00 inHg
- Observed at: LNR, 25 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 19930724025259A](https://openairdocs.org/incident/19930724025259A), Jul 24, 1993: Amtrvn VANSRV4, Lake Delton, WI, Destroyed, 1 fatal. Collided with trees while circling a residence.

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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