# NTSB NYC89FA129: Brantly Helicopter B-2, N2113U, Herkimer, NY, April 28, 1989

- Type: NTSB accident investigation
- Classification: Accident · Fatal · Field investigation · Final report
- Date: April 28, 1989, 10:30 local (14:30 UTC)
- Place: Herkimer, NY
- Coordinates: 43.019489, -74.990829 (estimated)
- Nearby events: https://openairdocs.org/map.md?lat=43.0195&lon=-74.9908&mi=10
- Phase of flight: [Enroute](https://openairdocs.org/ntsb-phases/400) (OpenAirDocs' grouping)
- Highest injury: Fatal
- Injuries: 1 fatal
- Status: Completed, report June 22, 1992
- Report: Approved by Office Director
- NTSB case key (mKey): 36284
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=NYC89FA129
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/36284/pdf
- Page: https://openairdocs.org/ntsb/NYC89FA129

## Probable cause

A FORCED LANDING IN UNSUITABLE TERRAIN DUE TO AN INTERNAL ENGINE FAILURE. THE ENGINE FAILURE SEQUENCE WAS INITIATED BY A FAILED OIL PRESSURE RELIEF SPRING WHICH HAD FAILED IN FATIGUE DUE TO IMPROPER PLATING OF THE SPRING. THE SPRING FAILURE CAUSED OIL STARVATION TO THE ENGINE CRANKSHAFT AND RESULTING FAILURE OF A CONNECTING ROD.

## 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 - normal
  - lubricating system,oil filter/screen - fatigue (cause)
  - maintenance - improper (cause)
  - material defect(inadequate quality of material) (cause)
  - lubricating system,oil filter/screen - failure,total (cause)
  - fluid,oil - starvation (cause)
  - engine assembly,crankshaft - overtemperature (cause)
  - engine assembly,connecting rod - failure,total (cause)
- Forced landing, maneuvering - turn to landing area (emergency)
- In flight collision with terrain/water, maneuvering - turn to landing area (emergency)
  - terrain condition - none suitable (cause)
  - terrain condition - high obstruction(s) (contributing factor)
  - object - tree(s) (contributing factor)

## Analysis

THE AIRCRAFT WAS FOUND IN A WOODED AREA ABOUT 1-1/2 MILES NORTH OF THE DEPARTURE HELIPORT. ON-SCENE INVESTIGATION REVEALED A HOLE IN THE ENGINE CASE NEAR CYLINDER #4. A LATER ENGINE TEARDOWN SHOWED THAT THE #4 CONNECTING ROD HAD FAILED AT THE CRANKSHAFT JOURNAL. THE JOURNAL DISPLAYED TYPICAL DISCOLORATION AND SCORING FROM OVERHEATING AND A LACK OF LUBRICATION. THE OIL PRESSURE RELIEF VALVE SPRING, P/N 68668, WAS BROKEN INTO 3 PIECES. METALLURGICAL EXAM REVEALED THAT THE SPRING FAILED IN FATIGUE WHICH PROBABLY ORIGINATED FROM PRE-EXISTING CRACKS DEVELOPED AS A RESULT OF HYDROGEN EMBRITTLEMENT. THE GENERAL CONDITION OF THE CADMIUM PLATING ON THE SPRING WAS VERY POOR, AND PLATING IS NOT CALLED OUT IN THE ENGINEERING DRAWING.

## Aircraft

- Registration: [N2113U](https://openairdocs.org/deregistered/N2113U-2013-04-09), registration cancelled 2013-04-09, S/N 161, built 1962 (OpenAirDocs)
- Reported make and model: Brantly Helicopter B-2
- Registry model: [Brantly B-2](https://openairdocs.org/model/brantly-b-2) (registry code 1440502) (OpenAirDocs)
- Registry engine: [Lycoming O&VO-360 series](https://openairdocs.org/engine/lycoming-o-vo-360-series) (registry code 41514, reciprocating) (OpenAirDocs)
- Category: Helicopter
- Serial number: 161
- Airframe hours: 897
- Engines: LYCOMING VO 360 180 horsepower reciprocating
- Damage: Destroyed
- Flight: Personal, Part 91
- Registered owner: Francis A. Dejohn
- Airworthiness certificate: Standard, Normal

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 74; commercial; airplane ratings: single-engine sea; medical: class 3, valid medical--no waivers/lim.; seat: right; toxicology performed

## Weather

- Conditions: Visual (VMC), Day
- Lowest ceiling: none

## 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 19890428010569A](https://openairdocs.org/incident/19890428010569A), Apr 28, 1989: Hynes B2, Herkimer, NY, Destroyed, 1 fatal. Engine failed shortly after departing private pad. Crashed in trees. Oil pressure relief valve spring broke.

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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