# NTSB LAX89DUQ05: Ruppercht Varieze, N393D, California City, CA, September 2, 1989

- Type: NTSB accident investigation
- Classification: Accident · Fatal · Final report
- Date: September 2, 1989, 00:00 local (07:00 UTC)
- Place: California City, CA
- Coordinates: 35.149639, -117.920059 (estimated)
- Nearby events: https://openairdocs.org/map.md?lat=35.1496&lon=-117.9201&mi=10
- Phase of flight: [Enroute](https://openairdocs.org/ntsb-phases/400) (OpenAirDocs' grouping)
- Highest injury: Fatal
- Injuries: 2 fatal
- Status: Completed, report July 22, 1992
- Report: Approved by Office Director
- NTSB case key (mKey): 26147
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=LAX89DUQ05
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/26147/pdf
- Page: https://openairdocs.org/ntsb/LAX89DUQ05

## Probable cause

THE WING FAILED DUE TO THE PILOT/OWNERS OVERTORQUING THE WING BOLTS AND THE IMPROPER INSTALLATION OF THE WING ATTACH PLATES/CONES.

## Sequence of events

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

- Airframe/component/system failure/malfunction, cruise
  - wing - failure,total (contributing factor)
  - wing,wing attachment fitting - improper (cause)
  - wing,wing attachment bolt - overtorque (cause)
  - maintenance,installation - improper, pilot in command (cause)
- In flight collision with terrain/water, descent - uncontrolled
  - terrain condition - water

## Analysis

THE PIC/OWNER/BUILDER DEPARTED CALIFORNIA CITY, CA, ON A LOCAL PERSONAL FLIGHT. A GND WITNESS REPORTED THE AIRPLANE WAS AT A HIGH ALTITUDE IN LEVEL FLIGHT WHEN SUDDENLY THE WINGS FOLDED. THE AIRPLANE THEN DESCENDED OUT OF CONTROL INTO A LAKE BED. WRECKAGE EXAMINATION DISCLOSED THAT ONE SET OF THE WING ATTACHMENT PLATE TAPER CONES AND THE RETAINING BOLTS WERE MISSING. THE REMAINING TAPER CONES WERE NOT SEATED PROPERLY AND THE RETAINING BOLTS WERE STRETCHED AND NECKED DOWN WHICH ARE CHARTERISTIC OF OVERTORQUING. THE REMAINING BOLTS APPEARED TO HAVE BEEN OVERTORQUED IN ORDER TO SEAT THEIR RESPECTIVE ATTACH CONES.

## Aircraft

- Registration: [N393D](https://openairdocs.org/deregistered/N393D-1990-07-16), registration cancelled 1990-07-16, S/N 393 (OpenAirDocs)
- Reported make and model: RUPPERCHT VARIEZE
- Registry model: [Rupprecht Myron S VARIEZE](https://openairdocs.org/model/rupprecht-myron-s-varieze) (registry code 05609JX) (OpenAirDocs)
- Category: Airplane, amateur-built
- Serial number: 393
- Airframe hours: 149
- Engines: CONTINENTAL O-200 100 horsepower reciprocating
- Damage: Destroyed
- Flight: Personal, Part 91
- Registered owner: Myron S. Rupprecht
- Airworthiness certificate: Special, Experimental (Special)
- Last inspection: Annual, May 20, 1989
- Departed: L71

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 59; commercial; airplane ratings: single-engine land; medical: class 3, valid medical--w/ waivers/lim; toxicology performed; flight hours: 1,691 total, 152 in this make and model, 1,600 as pilot in command, 5 in the last 90 days, 3 in the last 30 days

## Weather

- Conditions: Visual (VMC), Day
- Lowest ceiling: none

## 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 19890902033249A](https://openairdocs.org/incident/19890902033249A), Sep 2, 1989: Amtrru VARIEZE, California City, CA, Destroyed, 2 fatal. Over torqued wing bolts failed in flight possibly in acrobatic flight. Builder pilot used incorrect bolts.

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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