DFW05LA190

NTSB accident investigation · Bell 47G-4A · Black Oak, AR · July 15, 2005

Accident · No injuriesLimited investigationFinal report
Date
July 15, 2005, 13:45 local (18:45 UTC)
Place
Black Oak, AR
Injuries
1 uninjured
Damage
Substantial damage
Phase of flight
Maneuvering
Aircraft
N4087LBell 47G-4A
Weather
Visual (VMC) · Day
Status
Completed · report October 27, 2005
Report
Approved by Office Director
Parties
Federal Aviation Administration
FAA report
20050715016059A
Case key
62050

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 loss of engine power for undetermined reasons. A contributing factor was the lack of suitable terrain for the forced landing.

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 powerManeuvering - aerial application
Reason for occurrence undeterminedCause
Forced landingDescent - emergency
Loss of control - in flightDescent - uncontrolled
In flight collision with terrain/waterDescent - uncontrolled
Terrain condition - crop
Terrain condition - none suitableFactor

Analysis

The 10,370-hour commercial pilot was spraying the south end of a cotton field on a easterly heading at approximately 10 feet above the ground, when he heard the "engine [make] a surge in power." The pilot then scanned his engine instruments to see if he was having a problem, and all instrument indications were normal. The pilot then increased collective pitch after the helicopter began to lose altitude; however, the helicopter could not gain altitude. The helicopter impacted the ground in a level attitude, bounced into the air and began turning to the left. The pilot added left cyclic and thought he had the helicopter under control, when the left spray boom hit the cotton plants and started pulling the helicopter into the cotton. The helicopter subsequently "snapped" to the right and "started to tumble." The helicopter impacted terrain and came to rest on its right side. The reason for the reported engine power surge could not be determined.

Factual narrative

On July 15, 2005, approximately 1345 central daylight time, a single-engine Bell 47G-4A turbine powered helicopter, N4087L, was substantially damaged when it impacted terrain while maneuvering near Black Oak, Arkansas. The commercial pilot, sole occupant of the helicopter, was not injured. The helicopter was registered to and operated by Custom Air LLC, of Louisville, Mississippi. Visual meteorological conditions prevailed, and a flight plan was not filed for the 14 Code of Federal Regulations Part 137 aerial application flight. The local flight originated from a private heliport near Manila, Arkansas, approximately 1330.

The 10,370-hour pilot reported in the Pilot/Operator Aircraft Accident Report (NTSB Form 6120.1/2) that he was spraying the south end of a cotton field on a easterly heading. While spraying at approximately 10 feet above the ground, he reported hearing, the "engine [make] a surge in power." The pilot then scanned his engine instruments to see if he was having a problem; however, all instrument indications were normal.

The pilot added, he increased collective pitch when the helicopter began to lose altitude; however, the helicopter "could not gain altitude." The helicopter impacted the ground in a level attitude, bounced into the air and began turning to the left. The pilot then added left cyclic and thought he had the helicopter under control, when "the left spray boom hit the cotton [plants] and started pulling [the helicopter] into the cotton." The helicopter subsequently "snapped" to the right and "started to tumble." The helicopter impacted terrain and came to rest on its right side

Examination of the helicopter by the pilot revealed that the tail boom was severed, the main rotor blades were damaged, and both landing skids separated from the airframe.

The reason for the reported engine power surge could not be determined.

At 1353, the automated observing system at the Blytheville Municipal Airport, near Blytheville, Arkansas, located approximately 23 miles west of the accident site reported wind from 330 degrees at 8 knots, visibility 10 statute miles, few clouds at 4,100 feet, scattered clouds at 4,800 feet, and a broken cloud layer at 6,000 feet, temperature 81 degrees Fahrenheit, dew point 72 degrees Fahrenheit, and a barometric pressure of 29.91 inches of Mercury.

Aircraft

Registration
N4087L
Reported as
Bell 47G-4A
Category
Helicopter
Serial number
7698
Airframe hours
8,388
Engine
Allison T-63, 317 horsepower, turbo shaft
Damage
Substantial damage
Flight
Aerial application · Part 137
Operator
Custom Air LLC
Registered owner
Custom Air LLC
Airworthiness certificate
Special, Restricted (Special)
Last inspection
100 hour · July 1, 2005 · 26 hours before
Departed
Manilla, AR
Destination
Black Oak, AR

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
57
Injuries
None
Certificate
Commercial
Airplane ratings
Single-engine land
Medical
Class 2, With waivers/limitations
Last flight review
February 1, 2004
Seat
Left
Flight hours
10,370 total · 2,068 in this make and model · 10,264 as pilot in command

Weather

Conditions
Visual (VMC) · Day
Wind
330° at 8 knots
Visibility
10 statute miles
Lowest ceiling
6,000 ft broken
Temperature
81 °F, dew point 72 °F
Altimeter
29.90 inHg
Observed at
KHKA, 23 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.