CHI93LA320

NTSB accident investigation · Bell 47-G5 · Schaumburg, IL · August 12, 1993

Accident · Minor injuriesLimited investigationFinal report
Date
August 12, 1993, 12:30 local (17:30 UTC)
Place
Schaumburg, IL
Injuries
1 minor
Damage
Substantial damage
Phase of flight
Landing
Aircraft
N1347XBell 47-G5
Weather
Visual (VMC) · Day
Status
Completed · report August 17, 1994
Report
Approved by Office Director
FAA report
19930812029229A
Case key
9279

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

the pilot's improper autorotation techniques.

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.

Hard landingLanding - flare/touchdown
Precautionary landing - performedPilot in command
Autorotation - improperPilot in commandCause

Analysis

The aerial application helicopter took off with full fuel (55 gal.), and a full spray load (50 gal.). Witnesses reported the helicopter used the entire runway to get airborne. The helicopter was leveled off at 500 feet agl. The pilot stated he heard a loud bang and felt vibrations shortly after level off. He entered an autorotation. He said he flared the helicopter at 50 feet, but could not slow the rate of descent. The helicopter made a hard landing in a residential area. Post-landing investigation of the helicopter flight controls revealed no malfunction. A test run of the engine was performed without any problems.

Factual narrative

On August 12, 1993, at 1230 central daylight time, a Bell 47-G5 helicopter, N1347X, operated by Clarke Environmental Mosquito Control, Inc., Roselle, Illinois, sustained substantial damage from a hard autorotative landing near Schaumburg, Illinois. The commercial pilot received minor injuries. The aerial application flight originated at the Schaumburg Air Park at 1225. No flight plan was filed, and visual meteorological conditions prevailed at the time.

The helicopter was serviced at the Schaumburg Air Park before takeoff. The load was 50 gallons of spray mixture, and 55 gallons of fuel. Witnesses at the airport said the helicopter used the entire runway to become airborne.

The pilot reported he leveled off at 500 feet above ground level. After levelling off he heard a loud bang behind him, and the helicopter began to vibrate. The pilot said he entered an autorotation and picked out a landing site to his right. He flared the helicopter at 50 feet, and stated he felt no response when he raised the collective. The helicopter landed hard.

The helicopter was examined by an FAA Airworthiness Inspector. The inspector reported the flight control system was functional. The engine was examined, and a functional test run was performed. The inspector noted no problems with the engine.

Aircraft

Registration
N1347X
Reported as
Bell 47-G5
Category
Helicopter
Serial number
47-65
Engine
Lycoming VO-435-B1A, 260 horsepower, reciprocating
Damage
Substantial damage
Flight
Aerial application · Part 137
Registered owner
Clarke Mosquito Control
Airworthiness certificate
Standard, Normal
Last inspection
Annual · July 29, 1993 · 11 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
40
Certificate
Commercial
Instrument ratings
Helicopter
Medical
Class 2, Valid Medical--no waivers/lim.
Seat
Left
Flight hours
1,800 total · 250 in this make and model · 1,600 as pilot in command · 200 in the last 90 days · 50 in the last 30 days · 5 in the last 24 hours

Weather

Conditions
Visual (VMC) · Day
Wind
200° at 6 knots
Visibility
4 statute miles
Lowest ceiling
5,000 ft broken
Temperature
79 °F, dew point 72 °F
Altimeter
29.00 inHg
Observed at
ORD, 9 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.