LAX94LA200

NTSB accident investigation · Bell 47G-3B-1 · Yuma, AZ · April 17, 1994

Accident · No injuriesLimited investigationFinal report
Date
April 16, 1994, 20:00 local (Apr 17, 1994, 03:00 UTC)
Place
Yuma, AZ
Injuries
1 uninjured
Damage
Substantial damage
Phase of flight
Maneuvering
Aircraft
N304JPBell 47G-3B-1
Weather
Visual (VMC) · Dusk
Status
Completed · report November 14, 1994
Report
Approved by Office Director
FAA report
19940416009079A
Case key
28727

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

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Probable cause

an uncommanded engine deceleration to idle due to the improper installation of the throttle arm on the carburetor shaft.

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/malfManeuvering - aerial application
Throttle/power lever,bellcrank - separationCause
Maintenance,installation - improperOther maintenance personnelCause
Forced landingDescent - emergency
Hard landingLanding - flare/touchdown

Analysis

The pilot reported that the helicopter had completed a swath run and was pulling up to clear a line of trees when the engine decelerated to idle. The pilot entered an autorotation and landed hard, damaging the skids and the fuselage. Postaccident inspection of the engine revealed that the throttle arm had come off the carburetor throttle body shaft. The operator stated that the arm and shaft were new components, installed on February 24, 1994, by a contract mechanic. The operator also stated that an 'excessive amount (about 2 inches) of safety wire was on the arm, which allowed the arm to slip off the shaft.'

Factual narrative

On April 16, 1994, at 2000 mountain standard time, a Bell 47G-3B- 1 helicopter, N304JP, landed hard following a loss of engine power while engaged in aerial application operations near Yuma, Arizona. The helicopter was owned and operated by Sundown Helicopters, Inc., of Yuma, Arizona, under the provisions of 14 CFR Part 137 of the Federal Aviation Regulations. Visual meteorological conditions prevailed at the time and no flight plan was filed for the operation. The aircraft incurred substantial damage. The certificated commercial pilot, the sole occupant, was not injured. The flight originated from the field to be sprayed about 1915 hours on the day of the accident.

The operator and pilot reported that the helicopter had completed a swath run and was pulling up to clear a line of trees when the engine decelerated to idle. The pilot entered an autorotation and landed hard, damaging the skids and the fuselage.

Postaccident inspection of the engine revealed that the throttle arm had come off the carburetor throttle body shaft. The operator stated that the arm and shaft were new components, installed on February 24, 1994, by a contract mechanic. The operator also stated that an "excessive amount (about 2 inches) of safety wire was on the arm, which allowed the arm to slip off the shaft."

Aircraft

Registration
N304JP
Reported as
Bell 47G-3B-1
Category
Helicopter
Serial number
3598
Airframe hours
15,222
Engine
Lycoming V0-435-AIF, 260 horsepower, reciprocating
Damage
Substantial damage
Flight
Aerial application · Part 137
Operator
Sundown Helicopters, Inc.
Registered owner
Sundown Helicopters, Inc.
Airworthiness certificate
Special, Restricted (Special)
Last inspection
100 hour · April 4, 1994 · 23 hours before

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
47
Certificates
Flight instructor, Commercial
Airplane ratings
Single-engine land
Instrument ratings
Airplane, Helicopter
Medical
Class 2, Valid Medical--w/ waivers/lim
Seat
Left
Flight hours
15,163 total · 6,500 in this make and model · 14,637 as pilot in command · 167 in the last 90 days · 46 in the last 30 days · 3 in the last 24 hours

Weather

Conditions
Visual (VMC) · Dusk
Wind
320° at 2 knots
Visibility
40 statute miles
Lowest ceiling
None
Temperature
72 °F

FAA reports on this event · 1

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