# NTSB SEA83FA135: Enstrom 280C, N652H, Kent, WA, June 28, 1983

- Type: NTSB accident investigation
- Classification: Accident · Minor injuries · Field investigation · Final report
- Date: June 27, 1983, 17:44 local (Jun 28, 1983, 00:44 UTC)
- Place: Kent, WA
- Coordinates: 47.400001, -122.190368 (estimated)
- Nearby events: https://openairdocs.org/map.md?lat=47.4000&lon=-122.1904&mi=10
- Phase of flight: [Enroute](https://openairdocs.org/ntsb-phases/400) (OpenAirDocs' grouping)
- Highest injury: Minor injuries
- Injuries: 1 minor, 1 uninjured
- Status: Completed
- Report: Approved by Office Director
- NTSB case key (mKey): 39619
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=SEA83FA135
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/39619/pdf
- Page: https://openairdocs.org/ntsb/SEA83FA135

## Sequence of events

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

- Airframe/component/system failure/malfunction, cruise - normal
  - rotor drive system,tail rotor gearbox(90 deg) - worn (cause)
  - maintenance,lubrication - inadequate, other maintenance personnel (cause)
  - rotor drive system,tail rotor gearbox(90 deg) - other (cause)
- Loss of control - in flight, cruise
  - directional control - not possible, pilot in command (contributing factor)
- Forced landing, landing - flare/touchdown
  - autorotation - performed, pilot in command (contributing factor)
- In flight collision with terrain/water, landing - flare/touchdown

## Analysis

DURING A TRAFFIC REPORTING FLT FOR A RADIO STATION, THE PLT NOTED THE ONSET OF A SEVERE VIBRATION WHICH HE FELT THROUGH THE ANTITORQUE PEDALS. HE STATED THAT WITHIN SECONDS, THE HELICOPTER LOST DIRECTIONAL CONTROL & BEGAN A RAPID, UNCONTROLLED SPIN TO THE RIGHT. REPORTEDLY, THE HELICOPTER TUMBLED OUT OF CONTROL FOR A TIME. HOWEVER, THE PLT WAS ABLE TO REGAIN PARTIAL CONTROL AS IT ROLLED THRU A RELATIVELY UPRIGHT ATTITUDE. BEFORE CRASHING, THE RATE OF DESCENT WAS SLOWED WITH FULL COLLECTIVE & A ROTATING IMPACT OCCURRED IN A HORIZONTAL ATTITUDE. AN INVESTIGATION REVEALED THE TAIL ROTOR DRIVE SHAFT SPLINE COUPLING, PN 28-13609, HAD BECOME WORN. THE TEETH OF THE COUPLING WERE WORN AWAY & THERE WAS IRON OXIDE & CARBONIZED LUBRICANT WITHIN THE COUPLING. THE SPLINED MALE END OF THE COUPLING WOULD ROTATE WITHIN THE SPLINED FEMALE HOUSING. IT HAD ACCUMULATED 149.1 HRS SINCE LUBRICATED. THE LUBRICATION CHART & CHECK SHEET (PAGES MM-3-5 & MM-3-6 OF THE MAINTENANCE MANUAL) SHOW THAT THE COUPLING SHOULD BE LUBED AT 100 HR INTERVALS

## Aircraft

- Registration: [N652H](https://openairdocs.org/deregistered/N652H-1992-05-14), registration cancelled 1992-05-14, S/N 1102 (OpenAirDocs)
- Reported make and model: ENSTROM 280C
- Registry model: [Enstrom Helicopter 280C](https://openairdocs.org/model/enstrom-helicopter-280c) (registry code 3300505) (OpenAirDocs)
- Category: Helicopter
- Serial number: 1102
- Airframe hours: 3362
- Engines: LYCOMING HIO-360-E1BD 205 horsepower reciprocating
- Damage: Substantial damage
- Flight: Aerial observation, Part 91
- Registered owner: Paul W. Brendle, II
- Airworthiness certificate: Standard, Normal
- Last inspection: 100 hour, May 27, 1983, 96 hours before
- Departed: BFI, SEATTLE, WA

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 36; commercial; airplane ratings: single-engine land; medical: class 2, valid medical--w/ waivers/lim; seat: left; flight hours: 7,176 total, 5,740 in this make and model, 6,025 as pilot in command, 375 in the last 90 days, 5 in the last 24 hours

## Weather

- Conditions: Visual (VMC), Day
- Wind: 310° at 10 knots
- Visibility: 20 statute miles
- Lowest ceiling: none
- Altimeter: 30.00 inHg
- Observed at: RNT, 7 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 19830627027169A](https://openairdocs.org/incident/19830627027169A), Jun 27, 1983: Enstrm 280C, Kent, WA, Substantial damage. Lost tail rotor control. Crashed in a flat spin level attitude. Tail rotor drive shaft spline failure.

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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