# NTSB DEN83LU005: Eipper Quicksiver E (Modified), Sioux Falls, SD, September 24, 1983

- Type: NTSB accident investigation
- Classification: Accident · Fatal · Final report
- Date: September 24, 1983, 10:23 local (15:23 UTC)
- Place: Sioux Falls, SD
- Location: 43.5500° N, 96.7003° W: Placed by OpenAirDocs: center of Sioux Falls, SD, within about 6 miles (OpenAirDocs)
- Nearby events: https://openairdocs.org/map.md?lat=43.5500&lon=-96.7003&mi=10
- Phase of flight: [Maneuvering](https://openairdocs.org/ntsb-phases/450) (OpenAirDocs' grouping)
- Highest injury: Fatal
- Injuries: 1 fatal
- Status: Completed
- Report: Approved by Office Director
- NTSB case key (mKey): 16172
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=DEN83LU005
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/16172/pdf
- Page: https://openairdocs.org/ntsb/DEN83LU005

## Analysis

AFTER TAKEOFF, THE PLT OF THE WEIGHT-SHIFT CONTROLLED, ULTRALIGHT VEHICLE ENTERED A STEEP CLIMB, THEN BEGAN A SERIES OF MANEUVERS WHICH INCLUDED PAST VERTICAL WINGOVERS. REPORTEDLY, ON HIS LAST MANEUVER, HE PERFORMED A WHIP STALL. A GROUND WITNESS STATED THAT DURING THE RECOVERY, HE 'PULLED IN TIGHT TO GET AN IMPRESSIVE DIVE.' A PLT WITNESS & 2 FAA INSPECTORS REPORTED THAT WHEN THE NOSE DROPPED, IT WENT PAST A VERTICAL POSITION. THE PLT WITNESS STATED THAT DURING THE RECOVERY, THE PLT HELD THE NOSE IN APRX A 60 DEG DIVE FOR 3 TO 4 SEC. THE FAA INSPECTORS REPORTED THAT DURING THE PULL-OUT, THE WINGS FAILED. AN EXAM REVEALED THAT THE LEFT & RIGHT INBOARD COMPRESSION STRUTS HAD BUCKLED FROM POSITIVE LOADING. THE PLT HAD MODIFIED THE ULTRALIGHT BY INSTALLING A NON-STANDARD ENG-PROP REDUCTION DRIVE SYS, BY CHANGING THE PITCH TRIM, BY ADDING A LOWER TAIL BOOM BRACE & BY ADDING A 10 LB WT TO THE NOSE TO INCREASE THE FORWARD SPEED IN A DIVE.

## Sequence of events

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

- Airframe/component/system failure/malfunction, maneuvering
  - maintenance,modification - performed, pilot in command
  - aerobatics - performed, pilot in command (contributing factor)
  - overconfidence in aircraft's ability, pilot in command (contributing factor)
  - wing,bracing strut - buckled (cause)
  - design stress limits of aircraft - exceeded, pilot in command (cause)
- In flight collision with terrain/water, descent - uncontrolled

## Aircraft

- Registration: UNREG (not matched to a registry record)
- Reported make and model: EIPPER QUICKSIVER E (MODIFIED)
- Category: Ultralight, amateur-built
- Serial number: 1531
- Airframe hours: 16
- Engines: CUYUNA 430 30 horsepower reciprocating
- Damage: Destroyed
- Flight: Part 103
- Registered owner: Jack Zierke
- Departed: Y14, SIOUX FALLS, SD

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 48; airplane ratings: single-engine land; medical: unknown; seat: center

## Weather

- Conditions: Visual (VMC), Day
- Visibility: 15 statute miles
- Lowest ceiling: none
- Temperature: 64 °F

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

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