# NTSB NYC87FA114: Bell 47G, N13766, Wassaic, NY, March 19, 1987

- Type: NTSB accident investigation
- Classification: Accident · Fatal · Field investigation · Final report
- Date: March 19, 1987, 16:00 local (21:00 UTC)
- Place: Wassaic, NY
- Coordinates: 41.780059, -73.540885 (estimated)
- Nearby events: https://openairdocs.org/map.md?lat=41.7801&lon=-73.5409&mi=10
- Phase of flight: [Enroute](https://openairdocs.org/ntsb-phases/400) (OpenAirDocs' grouping)
- Highest injury: Fatal
- Injuries: 2 fatal
- Status: Completed, report October 6, 1988
- Report: Approved by Office Director
- NTSB case key (mKey): 30490
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=NYC87FA114
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/30490/pdf
- Page: https://openairdocs.org/ntsb/NYC87FA114

## 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 system,main rotor hub grip(sleeve) - failure,total (cause)
  - aircraft preflight - inadequate, pilot in command (contributing factor)
  - rotor system,main rotor blade - separation (cause)
  - maintenance,annual inspection - not performed, company maintenance personnel (contributing factor)
  - rotor system,main rotor blade - previous damage
  - maintenance,major repair - improper, company maintenance personnel (contributing factor)
- Loss of control - in flight, cruise - normal
- In flight collision with terrain/water, descent - uncontrolled
  - terrain condition - high obstruction(s)

## Analysis

THE BELL 47G HELICOPTER WAS ON A AERIAL SURVEY OF BURIED TELEPHONE CABLE WHEN THE RED MAIN ROTOR BLADE SEPARATED FROM THE BLADE GRIPS IN FLIGHT. THE MAIN ROTOR HUB WITH THE MAIN ROTOR BLADE SEPARATED FROM THE TRANSMISSION AND THE HELICOPTER CRASHED. NO EVIDENCE WAS FOUND TO INDICATE THAT THIS ACCIDENT INVOLVED A BLADE STRIKE. EXAMINATION OF THE FAILED MAIN ROTOR BLADE DISCLOSED THAT THE BLADE HAD RECEIVED A BLADE STRIKE SOME YEARS BEFORE, WAS REPAIRED AND RETURNED TO SERVICE. THERE WAS A LARGE GAP NEAR THE BLADE GRIPS THAT HAD BEEN FILLED WITH EPOXY. BOTH OF THESE REPAIRS WERE DETERMINED TO NOT BE IN COMPLIANCE WITH THE BELL 47 MAINTENANCE AND OVERHAUL MANUAL.

## Aircraft

- Registration: [N13766](https://openairdocs.org/deregistered/N13766-2015-04-30), registration cancelled 2015-04-30, S/N 1228, built 1958 (OpenAirDocs)
- Reported make and model: BELL 47G
- Registry model: [Bell 47G](https://openairdocs.org/model/bell-47g) (registry code 1181002) (OpenAirDocs)
- Registry engine: [Amateur-built UNKNOWN ENG](https://openairdocs.org/engine/amateur-built-unknown-eng) (registry code 99999) (OpenAirDocs)
- Category: Helicopter
- Serial number: 1228
- Airframe hours: 4395
- Engines: FRANKLIN 6V335-A 210 horsepower reciprocating
- Damage: Destroyed
- Flight: Aerial observation, Part 91
- Registered owner: New Hartford Helicopter Sev.
- Airworthiness certificate: Standard, Normal
- Last inspection: Unknown, March 7, 1987, 20 hours before
- Departed: 7B2, NORTHAMPTON, MA

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 37; commercial; medical: class 2, valid medical--no waivers/lim.; seat: left; toxicology performed; flight hours: 4,700 total

## Weather

- Conditions: Visual (VMC), Day
- Visibility: 20 statute miles
- Temperature: -0 °F, dew point -0 °F

## 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 19870319021489A](https://openairdocs.org/incident/19870319021489A), Mar 19, 1987: Bell 47G, Wassaic, NY, Destroyed, 2 fatal. Crashed during aerial survey. One main rotor blade 225 feet from wreckage. Tip weight missing. Prior blade repair.

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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