# NTSB ATL87LA105: Air & Space 18A, N6141S, Paducah, KY, April 5, 1987

- Type: NTSB accident investigation
- Classification: Accident · Serious injuries · Limited investigation · Final report
- Date: April 5, 1987, 10:00 local (15:00 UTC)
- Place: Paducah, KY
- Coordinates: 37.069858, -88.629722 (estimated)
- Nearby events: https://openairdocs.org/map.md?lat=37.0699&lon=-88.6297&mi=10
- Phase of flight: [Takeoff](https://openairdocs.org/ntsb-phases/300) (OpenAirDocs' grouping)
- Highest injury: Serious injuries
- Injuries: 1 serious
- Status: Completed, report March 10, 1988
- Report: Approved by Office Director
- NTSB case key (mKey): 7403
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=ATL87LA105
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/7403/pdf
- Page: https://openairdocs.org/ntsb/ATL87LA105

## Sequence of events

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

- Main gear collapsed, takeoff - roll/run
  - terrain condition - rough/uneven (cause)
  - unsuitable terrain or takeoff/landing/taxi area - selected, pilot in command (contributing factor)
  - remedial action - inadequate, pilot in command (cause)
  - condition(s)/step(s) not listed, manufacturer (contributing factor)
  - inadequate certification/approval,aircraft, faa(organization) (contributing factor)
  - design stress limits of aircraft - exceeded, pilot in command (cause)
  - landing gear,main gear - overload (contributing factor)
  - landing gear,main gear - failure,total (contributing factor)
- Dragged wing,rotor,pod,float or tail/skid, takeoff - roll/run
  - terrain condition - runway

## Analysis

THE PLT REPORTED THAT HE SPUN THE ROTOR UP TO 350 RPM IN PREPARATION FOR A MAXIMUM PERFORMANCE TAKEOFF. DURING TAKEOFF ROLL, THE GYROPLANE EXPERIENCED GROUND RESONANCE. THE PLT REDUCED THE THROTTLE TO IDLE, BUT THE OSCILLATIONS CONTINUED AND THE RT MAIN LDG GEAR COLLAPSED. THE ROTOR SUBSEQUENTLY STRUCK THE RUNWAY AND TORE LOOSE FROM THE GYROPLANE. THE PILOT NOTED THAT SLIGHT BARELY NOTICEABLE UNDULATIONS EXISTED IN THE PORTION OF THE RWY SURFACE USED DUIRNG THE TAKEOFF ROLL. THE FAA APPROVED FLT MANUAL (AFM) FOR THE GYROPLANE CONTAINS NO EMERGENCY OPERATION PROCEDURES FOR GROUND RESONANCE. THE ACFT OPERATOR REPORTED THAT THE PLT WAS TAUGHT TO TAKEOFF IF SUFFICIENT ROTOR RPM WAS AVAILABLE IN THE EVENT OF GROUND RESONANCE. THE AFM STATES THAT ANY AIRSPEED MAY BE USED FOR TAKEOFF IF THE ROTOR DOES NOT DECAY BELOW 140 RPM.

## Aircraft

- Registration: [N6141S](https://openairdocs.org/deregistered/N6141S-2016-08-31), registration cancelled 2016-08-31, S/N 18-49, built 1965 (OpenAirDocs)
- Reported make and model: AIR & SPACE 18A
- Registry model: [Air & Space America 18A](https://openairdocs.org/model/air-space-america-18a) (registry code 0440104) (OpenAirDocs)
- Registry engine: [Lycoming O&VO-360 series](https://openairdocs.org/engine/lycoming-o-vo-360-series) (registry code 41514, reciprocating) (OpenAirDocs)
- Category: Gyroplane
- Serial number: 18-49
- Airframe hours: 234
- Engines: LYCOMING O-360-A1D 180 horsepower reciprocating
- Damage: Substantial damage
- Flight: Personal, Part 91
- Registered owner: Farrington Aircraft Corp.
- Airworthiness certificate: Standard, Normal
- Last inspection: 100 hour, February 4, 1987, 5 hours before
- Airport: KY29, Farrongton Airpark, runway 4, 2,985 × 60 ft, asphalt

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 59; commercial, airline transport, flight instructor; airplane ratings: single-engine land, multi-engine land, single-engine sea; instrument ratings: airplane; medical: class 2, valid medical--w/ waivers/lim; seat: front; flight hours: 4,035 total, 27 in this make and model, 3,812 as pilot in command, 4 in the last 24 hours

## Weather

- Conditions: Visual (VMC), Day
- Wind: 340° at 8 knots
- Visibility: 25 statute miles
- Lowest ceiling: none
- Temperature: 66 °F, dew point 30 °F
- Altimeter: 30.00 inHg

## 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 19870405079179A](https://openairdocs.org/incident/19870405079179A), Apr 5, 1987: Airspc 18AIRSPC, Paducah, KY, Substantial damage. Maximum performance takeoff. Ground resonance on takeoff roll. Rotor struck ground. Right main gear collapsed.

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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