# NTSB ATL89MA070: Swearingen SX-300, N6Y, Wilmington, OH, January 9, 1989

- Type: NTSB accident investigation
- Classification: Accident · Fatal · Major investigation · Final report
- Date: January 9, 1989, 09:01 local (14:01 UTC)
- Place: Wilmington, OH
- Coordinates: 39.439212, -83.830703 (estimated)
- Nearby events: https://openairdocs.org/map.md?lat=39.4392&lon=-83.8307&mi=10
- Phase of flight: [Enroute](https://openairdocs.org/ntsb-phases/400) (OpenAirDocs' grouping)
- Highest injury: Fatal
- Injuries: 2 fatal
- Status: Completed, report June 1, 1989
- Report: Approved by Office Director
- NTSB case key (mKey): 8075
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=ATL89MA070
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/8075/pdf
- Page: https://openairdocs.org/ntsb/ATL89MA070

## Probable cause

FATIGUE AND RESULTING FAILURE OF THE RIGHT WING'S LOWER ATTACHMENT FITTING AND INADEQUATE QUALITY CONTROL BY THE SWEARINGEN SX-300 PRODUCTION/DESIGN PERSONNEL.

## Sequence of events

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

- Airframe/component/system failure/malfunction, cruise - normal
  - wing,wing attachment fitting - fatigue (cause)
  - inadequate quality control, production/design personnel (cause)
  - wing,wing attachment fitting - fractured (cause)
  - wing - separation
- Loss of control - in flight, cruise - normal
  - aircraft control - not possible
- In flight collision with terrain/water, descent - uncontrolled

## Analysis

THIS SX-300 (SA-29) WAS A PROOF-OF-CONCEPT ACFT BEING DEMONSTRATED FOR THE USAF AT WRIGHT-PATTERSON AFB. THE ACFT WAS CLEARED TO RESTRICTED AREA R5503 AT 8000 FT FOR A DEMONSTRATION. RADIO COMMUNICATIONS WITH INDIANAPOLIS ARTCC WERE ROUTINE; THERE WERE NO DISTRESS TRANSMISSIONS. ABOUT 7 MINUTES AFTER TAKEOFF THE ACFT WAS INVOLVED IN AN INFLIGHT BREAKUP. THE WRECKAGE PATH WAS ABOUT 1 MILE IN LENGTH WITH THE RT WING 3000 FEET FROM THE MAIN WRECKAGE. THE RT WING LOWER ATTACHMENT FITTING EXHIBITED A FATIGUE AREA WHICH PROGRESSED TO FAILURE FROM A WELD NUGGET NEAR THE INTERSECTION OF TWO WELD BEADS. PRE-EXISTING CRACKS WERE ALSO PRESENT IN THE LUG WELD AREA OF THE LEFT WING UPPER AND LOWER ATTACH- MENT FITTINGS. THE ACFT HAD BEEN IN SVC 571 HRS. IT WAS CERTIFIED AS AN EXPERIMENTAL CATEGORY EXHIBITION ACFT. THE DESIGNER HAD STATIC LOAD TESTED THE WINGS TO 6 G'S & SUSPECTED THE ACFT HAD BEEN SUBJECTED TO FLT LOADS APCHG 6 G'S. THE PLT TOLD AN ACQUAINTANCE THAT HE HAD ROUTINELY EXCEEDED THE 'RED LINE' BY 85 MPH.

## Aircraft

- Registration: [N6Y](https://openairdocs.org/aircraft/N6Y), registered now, S/N 001, built 1989 (OpenAirDocs)
- Reported make and model: SWEARINGEN SX-300
- Registry model: [Aerokit SA32-T](https://openairdocs.org/model/aerokit-sa32-t) (registry code 0568008) (OpenAirDocs)
- Registry engine: [Allison 250-B17 series](https://openairdocs.org/engine/allison-250-b17-series) (registry code 03017, turbo-prop) (OpenAirDocs)
- Category: Airplane
- Serial number: 001
- Airframe hours: 571
- Engines: LYCOMING IO-540-L1C5 300 horsepower reciprocating
- Damage: Destroyed
- Fire: On-Ground
- Flight: Part 91
- Registered owner: Jafftech Industries, Inc.
- Airworthiness certificate: Special, Experimental (Special)
- Last inspection: Annual, March 24, 1988, 87 hours before
- Departed: FFO, DAYTON, OH
- Flight plan: IFR

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 55; commercial; airplane ratings: multi-engine land, single-engine land; instrument ratings: airplane; medical: class 2, valid medical--no waivers/lim.; seat: left; toxicology performed; flight hours: 7,754 total, 145 in this make and model, 30 in the last 90 days, 22 in the last 30 days, 5 in the last 24 hours

## Weather

- Conditions: Visual (VMC), Day
- Wind: 220° at 10 knots
- Visibility: 15 statute miles
- Lowest ceiling: 12,000 ft broken
- Temperature: 25 °F, dew point 16 °F
- Altimeter: 30.00 inHg
- Observed at: FFO, 18 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 19890109000349A](https://openairdocs.org/incident/19890109000349A), Jan 9, 1989: Amtres SX300, Wilmington, OH, Destroyed, 2 fatal. Right wing spar failed during high stress loading due fatigue cracks. Aircraft spiraled out of control to impact.

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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