# NTSB NYC89DNE01: Bell 47D1, N163B, Russell, MA, December 2, 1988

- Type: NTSB accident investigation
- Classification: Accident · Fatal · Final report
- Date: December 2, 1988, 10:15 local (15:15 UTC)
- Place: Russell, MA
- Location: 42.2039° N, 72.8619° W: Placed by OpenAirDocs: center of Russell, MA, within about 6 miles (OpenAirDocs)
- Nearby events: https://openairdocs.org/map.md?lat=42.2039&lon=-72.8619&mi=10
- Phase of flight: [Enroute](https://openairdocs.org/ntsb-phases/400) (OpenAirDocs' grouping)
- Highest injury: Fatal
- Injuries: 1 fatal
- Status: Completed, report June 11, 1990
- Report: Approved by Office Director
- NTSB case key (mKey): 36247
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=NYC89DNE01
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/36247/pdf
- Page: https://openairdocs.org/ntsb/NYC89DNE01

## Probable cause

A PILOT INDUCED LOW ROTOR RPM CONDITION, FOLLOWED BY BLADE FLAPPING AS THE MAIN ROTOR BLADE CONTACTED THE TAIL OF THE HELICOPTER.

## Sequence of events

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

- Loss of control - in flight, cruise
  - rotorcraft flight controls - improper use of, pilot in command (cause)
  - rotor rpm - not maintained, pilot in command (cause)
  - aircraft handling - not possible, pilot in command
- In flight collision with terrain/water, descent - uncontrolled
  - terrain condition - high vegetation

## Analysis

THE BELL 47D1 WAS ON A SOLO X-COUNTRY FLIGHT WITH A COMMERCIAL RATED (NON-ROTORCRAFT RATED) PILOT WHO WAS WORKING ON HIS ROTORCRAFT RATING. THE HELICOPTER CRASHED IN A WOODED AREA WITH DEBRIS SPREAD ALONG THE FLIGHT PATH FOR OVER 1/4 MILE. POST CRASH EXAMINATION SHOWED THAT ONE STABILIZER BAR WAS MISSING FROM THE ROTOR HEAD AND HAD FAILED OPPOSITE THE DIRECTION OF ROTATION. THE STABILIZER BAR WAS NOT RECOVERED. THERE WAS EVIDENCE OF BLADE FLAPPING AND LOW ROTOR RPM CONDITIONS. NO EVIDENCE OF A FAILURE ON THE FLIGHT CONTROL SYSTEM, OTHER THAN THE MISSING STABILIZER CONTROL BAR WAS FOUND. NO EVIDENCE OF A ENGINE FAILURE WAS NOTED, ALTHOUGH CONDITIONS WERE PRESENT FOR THE FORMATION OF CARBURETOR ICE.

## Aircraft

- Registration: [N163B](https://openairdocs.org/deregistered/N163B-1992-02-25), registration cancelled 1992-02-25, S/N 17 (OpenAirDocs)
- Reported make and model: BELL 47D1
- Registry model: [Bell 47D1](https://openairdocs.org/model/bell-47d1) (registry code 1180802) (OpenAirDocs)
- Category: Helicopter
- Serial number: 17
- Engines: FRANKLIN 6V-335-A 200 horsepower reciprocating
- Damage: Destroyed
- Flight: Instructional, Part 91
- Registered owner: Associated Air Services, Inc.
- Airworthiness certificate: Standard, Normal
- Last inspection: 100 hour, November 18, 1988, 12 hours before
- Departed: BAF, WESTFIELD, MA
- Destination: GBR, GRT. BARRINGTON, MA
- Airport: Unknown

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 46; commercial, flight instructor; airplane ratings: single-engine sea, single-engine land, multi-engine land; instrument ratings: airplane; medical: class 2, valid medical--no waivers/lim.; seat: left; toxicology performed; flight hours: 1,218 total, 42 in this make and model, 21 in the last 90 days, 9 in the last 30 days

## Weather

- Conditions: Day
- Wind: 300° at 13 knots
- Visibility: 35 statute miles
- Lowest ceiling: 3,000 ft unknown
- Temperature: 32 °F, dew point 18 °F
- Altimeter: 30.00 inHg
- Observed at: BAF, 8 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 19881202052349A](https://openairdocs.org/incident/19881202052349A), Dec 2, 1988: Bell 47D1, Russell, MA, Destroyed, 1 fatal. Indicates student got too slow in flight. Mast bumping. Blade flapping. Rotor speed decay. Carb icing possibility.

## Other investigations on N163B (4)

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 FTW76FPG68](https://openairdocs.org/ntsb/FTW76FPG68), Jun 17, 1976: Bell 47B (N163B), Ravenden, AR, substantial damage
- [NTSB FTW74DPG10](https://openairdocs.org/ntsb/FTW74DPG10), Aug 9, 1973: Bell 47G (N163B), Black Rock, AR, substantial damage
- [NTSB MKC69F0060](https://openairdocs.org/ntsb/MKC69F0060), Jun 25, 1968: Bell 47G (N163B), Garden City, KS, substantial damage
- [NTSB MKC68A0038](https://openairdocs.org/ntsb/MKC68A0038), Jun 25, 1967: Bell 47G (N163B), Creston, IA, substantial damage

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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