NYC85LA005

NTSB accident investigation · Bell 47G3-B1 · Moultonboro, NH · October 7, 1984

Accident · No injuriesLimited investigationFinal report

Date: October 7, 1984, 17:55 local (21:55 UTC)
Place: Moultonboro, NH
Injuries: 3 uninjured
Damage: Substantial damage
Phase of flight: Enroute
Aircraft: N401GCBell 47G3-B1
Weather: Visual (VMC) · Day
Status: Completed
Report: Approved by Office Director
FAA report: 19841007076179A
Case key: 35629

From the NTSB’s public API. By law, NTSB reports can’t be used as evidence in lawsuits over the accident.

On this page

Sequence of events

NTSB’s coding before 2008: each occurrence and phase of flight, and the causes and factors under it. The codes are defined in NTSB’s coding manual.

Loss of engine power(total) - mech failure/malfClimb

Engine assembly,valve,intake - disabledCause

Forced landingDescent - emergency

Autorotation - performedPilot in command

In flight collision with terrain/waterLanding

Terrain condition - mountainous/hillyFactor

Terrain condition - high vegetationFactor

Object - tree(s)Factor

Analysis

Acft was climbing through a mountain saddle when the engine began to backfire and lose power. Plt entered autorotation & settled into trees on autorotative flare. Engine inspection revealed #3 cylinder intake valve springs broken.

Aircraft

Registration: N401GC
Reported as: Bell 47G3-B1
Category: Helicopter
Serial number: 3568
Airframe hours: 5,822
Engine: Lycoming VO-435-A1F, 270 horsepower, reciprocating
Damage: Substantial damage
Flight: Part 135
Registered owner: Vermont Travelers, Inc.
Airworthiness certificate: Standard, Utility; Standard, Normal
Last inspection: 100 hour · February 27, 1984 · 89 hours before
Departed: HN08 · Moultonboro, VT
Airport: Moultonboro

N401GCRegistration cancelled Apr 4, 1990 · Bell TH-13TS/N 3568 Airframe modelBell TH-13T

Matched to the registry by N-number and the event date; the registry’s history has gaps, so older matches can be wrong. Compare the reported make and model.

Flight crew

As NTSB recorded them. NTSB leaves out names.

Role: Pilot
Age: 44
Certificate: Commercial
Instrument ratings: Helicopter
Medical: Valid Medical--no waivers/lim.
Seat: Left
Flight hours: 2,229 total · 295 in this make and model · 1,996 as pilot in command · 245 in the last 90 days · 6 in the last 24 hours

Weather

Conditions: Visual (VMC) · Day
Visibility: 12 statute miles
Lowest ceiling: None
Temperature: 52 °F

FAA reports on this event · 1

The FAA’s own accident and incident reports, matched to the aircraft by N-number and date.

Accident 19841007076179ABell TH13T · Moultonboro, NHSettled into trees after power loss during cruise flight. Intake valve springs broken, spark plug electrodes worn.Oct 7, 1984 · N401GC · Substantial damage