# NTSB NYC91DFA02: Hayes Kolb/Twinstar, N71817, Round Lake, NY, January 27, 1991

- Type: NTSB accident investigation
- Classification: Accident · Fatal · Final report
- Date: January 27, 1991, 16:50 local (20:50 UTC)
- Place: Round Lake, NY
- Coordinates: 42.930622, -73.790245 (estimated)
- Nearby events: https://openairdocs.org/map.md?lat=42.9306&lon=-73.7902&mi=10
- Phase of flight: [Approach](https://openairdocs.org/ntsb-phases/500) (OpenAirDocs' grouping)
- Highest injury: Fatal
- Injuries: 1 fatal
- Status: Completed, report May 3, 1993
- Report: Approved by Office Director
- NTSB case key (mKey): 36748
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=NYC91DFA02
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/36748/pdf
- Page: https://openairdocs.org/ntsb/NYC91DFA02

## Probable cause

IN-FLIGHT STRUCTURAL FAILURE OF THE OUTBOARD WING ATTACHMENT FITTINGS ON BOTH WINGS DUE TO AN UNDETERMINED REASON.

## Sequence of events

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

- Airframe/component/system failure/malfunction, approach - vfr pattern - final approach
  - procedures/directives - not followed, pilot in command
  - qualification, pilot in command
  - maintenance,recordkeeping - inadequate, company/operator management
  - wing,bracing strut - failure,total (cause)
  - reason for occurrence undetermined (cause)
- In flight collision with terrain/water, descent - uncontrolled

## Analysis

THE AMATEUR BUILT ACFT WAS ON ITS 1ST FLT AFTER BEING CONSTRUCTED.  IT FLEW ABOUT 5 MIN BEFORE THE OWNER/BUILDER/PLT RETURNED THE PLANE FOR LANDING.  AT ABOUT 75 FT AGL ON FINAL APCH, BOTH WINGS FAILED & THE ACFT CRASHED.  INVESTIGATION REVEALED THAT STEEL BOLTS WERE MISSING FROM THE OUTBOARD WING STRUT ATTACHMENT FITTINGS, RIVETS THAT HELD THE OUTBOARD ATTACHMENT FITTINGS TO THE WING HAD SHEARED OFF.  THE REASON FOR THE MISSING BOLTS AND SHEARED REVITS WAS NOT VERIFIED. THE ACFT HAD BEEN REGISTERED WITH THE FAA, BUT THERE WAS NO AIRWORTHINESS CERTIFICATE.  ALSO, NO WEIGHT & BALANCE DATA WAS FOUND IN THE ACFT, THE PLT WAS NOT AN FAA CERTIFIED AIRMAN, NOR DID HE POSSESS A VALID FAA MEDICAL CERTIFICATE.

## Aircraft

- Registration: [N71817](https://openairdocs.org/deregistered/N71817-1997-03-14), registration cancelled 1997-03-14, S/N TS281 (OpenAirDocs)
- Reported make and model: HAYES KOLB/TWINSTAR (KOLB/TWINS)
- Registry model: [Hayes Clifford G KOLB TWINSTAR](https://openairdocs.org/model/hayes-clifford-g-kolb-twinstar) (registry code 0561854) (OpenAirDocs)
- Category: Airplane, amateur-built
- Engines: ROTAX 503 47 horsepower reciprocating
- Damage: Substantial damage
- Flight: Personal, Part 91
- Registered owner: Clifford G Hayes
- Airport: NY46, Round Lake, runway 14, 2,000 × 60 ft, grass/turf

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 38; seat: left

## Weather

- Conditions: Visual (VMC), Dusk
- Wind: variable at 5 knots
- Visibility: 7 statute miles
- Temperature: -0 °F, dew point -0 °F

## 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 19910127000999A](https://openairdocs.org/incident/19910127000999A), Jan 27, 1991: Amtrkb TWINSTAR, Round Lake, NY, Substantial damage, 1 fatal. Wings folded on landing approach home built on first test flight fell to ground. Strut attach bolts were missing.

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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