# NTSB SEA86LA143: Bell 47G-2, N11VH, Zillah, WA, June 12, 1986

- Type: NTSB accident investigation
- Classification: Accident · No injuries · Limited investigation · Final report
- Date: June 12, 1986, 04:45 local (11:45 UTC)
- Place: Zillah, WA
- Coordinates: 47.20058, -120.899261 (estimated)
- Nearby events: https://openairdocs.org/map.md?lat=47.2006&lon=-120.8993&mi=10
- Phase of flight: [Enroute](https://openairdocs.org/ntsb-phases/400) (OpenAirDocs' grouping)
- Highest injury: No injuries
- Injuries: 1 uninjured
- Status: Completed
- Report: Approved by Office Director
- NTSB case key (mKey): 40421
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=SEA86LA143
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/40421/pdf
- Page: https://openairdocs.org/ntsb/SEA86LA143

## Sequence of events

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

- Loss of engine power(total) - mech failure/malf, cruise
  - engine assembly,connecting rod - overtemperature (cause)
  - engine assembly,connecting rod - failure,total (cause)
  - engine assembly,bearing - worn (cause)
- Forced landing, descent - emergency
  - autorotation - attempted, pilot in command
- In flight collision with object, landing
  - object - building(nonresidential) (contributing factor)

## Analysis

EN ROUTE TO THE LOCAL SPRAY AREA A TOTAL LOSS OF POWER OCCURRED ALONG WITH A LOSS OF OIL PRESSURE. THE ACFT WAS APRX 200 FT AGL OVER A PEAR ORCHARD. THE PLT WAS ATTEMPTING TO AUTOROTATE ONTO A NEARBY ROAD BUT THE LEFT SKID CAUGHT THE ROOF TOP OF A METAL SHED. THE HELICOPTER CRASHED THROUGH THE ROOF OF THE SHED AND ROLLED OVER ONTO ITS SIDE. INVESTIGATION REVEALED THAT THE NUMBER THREE CYLINDER ROD BOLT HAD FAILED. METALLURGICAL EXAM REVEALED THAT THE NUMBER 3 CYLINDER CONNECTING ROD CAP HAD FAILED AS A RESULT OF OVERSTRESS FORCES DUE TO EXCESSIVE HEATING OF THE ROD AND CAP. FAILURE OF THE NUMBER 3 CYLINDER CONNECTING ROD BOLT WAS DUE TO FATIGUE CRACKING. THE MOST LIKELY CAUSE OF THE OVERHEATING WAS DUE TO A DETERIORATED BEARING.

## Aircraft

- Registration: [N11VH](https://openairdocs.org/deregistered/N11VH-2011-07-19), registration cancelled 2011-07-19, S/N 2027, built 1958 (OpenAirDocs)
- Reported make and model: BELL 47G-2
- Registry model: [Bell 47G-2](https://openairdocs.org/model/bell-47g-2) (registry code 1181008) (OpenAirDocs)
- Registry engine: [Lycoming VO-435 series](https://openairdocs.org/engine/lycoming-vo-435-series) (registry code 41525, reciprocating) (OpenAirDocs)
- Category: Helicopter
- Serial number: 2027
- Airframe hours: 9124
- Engines: LYCOMING TVO-435-BIA 270 horsepower reciprocating
- Damage: Destroyed
- Flight: Aerial application, Part 137
- Registered owner: Valicopters, Inc.
- Airworthiness certificate: Special, Restricted (Special)
- Last inspection: 100 hour, January 22, 1986, 82 hours before
- Departed: BUENA, WA

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 25; commercial; airplane ratings: single-engine land, multi-engine land; instrument ratings: airplane; medical: class 1, valid medical--no waivers/lim.; seat: front; flight hours: 2,086 total, 800 in this make and model, 1,894 as pilot in command, 85 in the last 90 days, 3 in the last 24 hours

## Weather

- Conditions: Visual (VMC), Dawn
- Wind: calm
- Visibility: 50 statute miles
- Lowest ceiling: none
- Temperature: 64 °F
- Altimeter: 29.00 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 19860612029399A](https://openairdocs.org/incident/19860612029399A), Jun 12, 1986: Bell 47G2, Zillah, WA, Destroyed. The engine lost power after takeoff and the helicopter landed on a shed. A cylinder rod bolt failed from fatigue.

## Other investigations on N11VH (6)

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.

- [NTSB SEA99LA149](https://openairdocs.org/ntsb/SEA99LA149), Aug 26, 1999: Bell 47G-2 (N11VH), Benton City, WA, destroyed, 1 fatal. Probable cause: A loss of power for undetermined reasons and the failure of the pilot to maintain adequate rotor RPM following the power loss. Contributing factors were the pilot's lack of certification and total…
- [NTSB SEA85LA155](https://openairdocs.org/ntsb/SEA85LA155), Jul 2, 1985: Bell 47G2 (N11VH), Roosevelt, WA, substantial damage
- [NTSB SEA84LA132](https://openairdocs.org/ntsb/SEA84LA132), Jun 14, 1984: Bell 47G2A (N11VH), Buena, WA, substantial damage
- [NTSB SEA82DA072](https://openairdocs.org/ntsb/SEA82DA072), May 18, 1982: Bell 47G-2 (N11VH), Grandview, WA, substantial damage
- [NTSB SEA82DA050](https://openairdocs.org/ntsb/SEA82DA050), Apr 10, 1982: Bell 47G-2A (N11VH), Lyle, WA, substantial damage
- [NTSB FTW74FPJ06](https://openairdocs.org/ntsb/FTW74FPJ06), Aug 16, 1973: EL Tomcat MK5 (N11VH), Springer, OK, substantial damage, 1 fatal

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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