# NTSB BFO90LA065: Robinson R22, N9017S, Paducah, KY, July 27, 1990

- Type: NTSB accident investigation
- Classification: Accident · No injuries · Limited investigation · Final report
- Date: July 27, 1990, 15:30 local (19:30 UTC)
- Place: Paducah, KY
- Coordinates: 37.010658, -88.579048 (estimated)
- Nearby events: https://openairdocs.org/map.md?lat=37.0107&lon=-88.5790&mi=10
- Phase of flight: [Takeoff](https://openairdocs.org/ntsb-phases/300) (OpenAirDocs' grouping)
- Highest injury: No injuries
- Injuries: 2 uninjured
- Status: Completed, report November 23, 1992
- Report: Approved by Office Director
- NTSB case key (mKey): 11606
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=BFO90LA065
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/11606/pdf
- Page: https://openairdocs.org/ntsb/BFO90LA065

## Probable cause

THE LOSS OF TAIL ROTOR THRUST DUE TO IMPROPER PART INSTALLATION.

## Sequence of events

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

- Airframe/component/system failure/malfunction, takeoff
  - rotor drive system - failure,partial (cause)
  - maintenance,installation - improper, other maintenance personnel (contributing factor)
  - material inadequate,improper, other maintenance personnel (contributing factor)
  - directional control - not possible, pilot in command
- Hard landing, takeoff - aborted

## Analysis

THE HELICOPTER IMPACTED TO THE GROUND AFTER A LOSS OF TAIL ROTOR THRUST DURING AN ATTEMPTED TAKEOFF. INVESTIGATION REVEALED THE INTERMEDIATE FLEX PLATE AND TWO CLUTCH YOKES AND FAILED. A METALLURGICAL EXAMINATION REVEALED THAT THE WASHERS IN ONE OF THE FASTENER JOINTS WERE MISPLACED. A WARNING IN THE MANUFACTURER'S MANUAL STATES: 'A559 NICKEL-PLATED RADIUSED WASHERS ARE REQUIRED ON EACH SIDE OF THE A193 FLEXPLATES OR FRETTING FAILURE MAY OCCUR WITHIN A FEW HOURS.' RECORDS INDICATE THE MOST RECENT ANNUAL INSPECTION WAS SIGNED OFF ON OCTOBER 19, 1989, AND THE AIRCRAFT HAD ACCUMULATED 119 HOURS SINCE THAT TIME. THE HELICOPTER HAD UNDERGONE A PRE-PURCHASE INSPECTION ABOUT ONE MONTH PRIOR TO THE ACCIDENT.

## Aircraft

- Registration: N9017S (not matched to a registry record)
- Reported make and model: ROBINSON R22
- Category: Helicopter
- Serial number: 0195
- Airframe hours: 2038
- Engines: LYCOMING O-320 150 horsepower reciprocating
- Damage: Substantial damage
- Flight: Personal, Part 91
- Operator: Byrne, Michael T.
- Last inspection: Annual, October 19, 1989, 119 hours before

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 40; private; medical: class 2, valid medical--no waivers/lim.; flight hours: 221 total, 187 as pilot in command

## Weather

- Conditions: Visual (VMC), Day
- Wind: 40° at 5 knots
- Visibility: 4 statute miles
- Lowest ceiling: none
- Temperature: 91 °F, dew point 66 °F
- Altimeter: 30.00 inHg

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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