MIA96LA210

NTSB accident investigation · Bell 47G-4A · Adel, GA · August 11, 1996

Accident · FatalLimited investigationFinal report
Date
August 11, 1996, 11:15 local (15:15 UTC)
Place
Adel, GA
Injuries
1 fatal, 1 serious; on the ground: 1 serious
Damage
Destroyed
Phase of flight
Maneuvering
Aircraft
N9472GBell 47G-4A
Weather
Visual (VMC) · Day
Status
Completed · report February 5, 1998
Report
Approved by Office Director
FAA report
19960811022109A
Case key
38072

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

On this page

Probable cause

the pilot's misjudgment of clearance between the helicopter and the antenna. A factor relating to the accident was the pilot's use of a drug (medication) that had sedative effects.

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.

In flight collision with objectHover - out of ground effect
Object - antenna
Clearance - misjudgedPilot in commandCause
Impairment(drugs)Pilot in commandFactor
Procedures/directives - not followedPilot in command
Lack of certificationPilot in command
Maintenance,recordkeeping - improperPilot in command
In flight collision with terrain/waterDescent - uncontrolled

Analysis

The pilot was hovering the helicopter above a radio tower as a worker was attaching a 50 foot line from the helicopter to an antenna on the tower. As the helicopter maneuvered above the tower, it settled, and the main rotor blades collided with the antenna and mounting pole. The main rotor separated from the helicopter, and the helicopter descended uncontrolled until ground impact. The worker's left ankle was broken when the helicopter hit the antenna. The winds were reported to be steady at about 15 mph with no gusts. Toxicology tests of specimens from the pilot showed 0.214 mcg/ml diphenhydramine in blood, 0.597 mcg/ml diphenhydramine in liver fluid, and diphenhydramine was detected in his urine. Diphenhydramine is an antihistamine with sedative effects. FAA records showed the helicopter operator held a Title 14 CFR Part 137 Aerial Application Certificate, but there was no record that the operator held a 14 CFR Part 133 External Load Certificate. Also, the logbook showed no record of an FAA Form 337, Major Repair and Alteration, for installation of the external load hook, which reportedly had been installed by the pilot about a week before the accident.

Factual narrative

On August 11, 1996, about 1115 eastern daylight time, a Bell 47G-4A, N9472G, registered to Coker Helicopter, Inc., collided with a television antenna near Adel, Georgia, while workers were attempting to hook an external line to the antenna to remove it from the tower. Visual meteorological conditions prevailed at the time. No flight plan was filed for the Title 14 CFR Part 91 external lift flight. The helicopter was destroyed and the commercial-rated pilot was fatally injured. One worker on the tower received serious injuries and one worker was not injured. The flight originated from the base of the tower a few minutes before the accident.

A worker who was located on the tower stated he and another worker had been lifted to the top of the tower by a 50-foot line connected to the bottom of the helicopter. They had partially unbolted the antenna at the top of the tower. The other worker was on the antenna and was attempting to connect the 50-foot line from the helicopter to the antenna, so it could be lifted from the tower. This worker had the line wrapped around the antenna. As the helicopter maneuvered above the tower, it settled down and the main rotor blades collided with the antenna and mounting pole. The main rotor separated from the helicopter and it descended uncontrolled until ground impact. The other worker's left ankle was broken when the helicopter hit the antenna. The winds were blowing steady at about 15 mph at the time of the accident and there were no gusts.

Postmortem examination of the pilot was performed by Dr. Carol A. Terry, Georgia Division of Forensic Sciences, Decatur, Georgia. The cause of death was attributed to multiple blunt force injuries. No findings which could be considered causal to the accident were reported.

Postmortem toxicology tests on specimens obtained from the pilot were performed by Georgia Division of Forensic Sciences and Dr. Dennis V. Canfield, Manager FAA Toxicology Laboratory, Oklahoma City, Oklahoma. The tests were negative for carbon monoxide, ethanol alcohol, basic, acidic, and neutral drugs. The tests were positive for .241 ug/ml Diphenhydramine in blood, .597 ug/ml Diphenhydramine in liver fluid, and a detection of Diphenhydramine in urine See attached toxicology reports.

The Physicians' Desk Reference (PDR) identifies Diphenhydramine as an antihistamine drug. The PDR states patients taking Diphenhydramine should be advised that this drug may cause drowsiness and has an additive effect with alcohol. Patients should be warned about engaging in activities requiring mental alertness such as driving a car or operating appliances, machinery, ect. See attached pages from the PDR.

Federal Aviation Administration records shows the helicopter operator, Coker Helicopter, Inc., holds a Title 14 CFR Part 137 Aerial Application certificate. There was no record that the operator held a 14 CFR Part 133 External Load certificate. Additionally, aircraft logbook records showed no FAA Form 337, Major Repair and Alteration, for installation of the external load hook, which was reported by the pilot's family to have been installed by the pilot a week before the accident.

Aircraft

Registration
N9472G
Reported as
Bell 47G-4A
Category
Helicopter
Serial number
7519
Airframe hours
11,900
Engine
Allison 250-C20, 317 horsepower, turbo shaft
Damage
Destroyed
Fire
On-Ground
Flight
Part 91
Registered owner
Coker Helicopter, Inc.
Airworthiness certificate
Special, Restricted (Special)
Last inspection
100 hour · March 15, 1996

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
42
Certificate
Commercial
Airplane ratings
Single-engine land
Medical
Class 2, Valid Medical--w/ waivers/lim
Seat
Left
Toxicology
Performed
Flight hours
9,600 total · 9,500 in this make and model

Weather

Conditions
Visual (VMC) · Day
Wind
160° at 15 knots
Visibility
6 statute miles
Lowest ceiling
6,000 ft broken
Temperature
84 °F, dew point 79 °F
Altimeter
30.00 inHg
Observed at
VLD, 25 nm away

Docket · 7

The files NTSB released with the investigation on March 31, 1997, on NTSB’s docket system: statements, records, photos and specialists’ reports. 1.7 MB in all.

FAA reports on this event · 1

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