Aircraft Accident/Incident Report

Delaplaine, Arkansas 72425
Tuesady, June 2, 1998 18:15 CDT

NTSB Narrative Summary Released at Completion of Accident

The helicopter was traveling in an easterly direction at an airspeed of 60 knots, while maintaining a constant 5 foot clearance over the rice field, when the transmission failed. The pilot turned the helicopter to the right to avoid a tall tree, as he simultaneously initiated a forced landing. During the touchdown on soft ground, both skids and the collapsed and the tailboom was severed by the main rotor blades. According to the maintenance records, the main transmission (part number 23700-9, serial number 617), which has a recommended TBO of 1,200 hours, had accumulated 1,048 hours since its last overhaul in 1993. According to the manufacturer, the 23700-9 transmissions are subject to a recurring inspection of the oil filter every 50 flight hours in accordance with Airworthiness Directive 81-17-03. According to the maintenance logbooks, the last compliance with AD 81-17-03 was 340 hours prior to the accident, on March 26, 1996. Examination of the transmission by the manufacturer's representative revealed a massive failure of the first stage planetary gear system due to lack of lubrication.

NTSB Probable Cause Narrative

The failure of maintenance personnel to comply with and airworthiness directive, which resulted in failure of the planetary gear due to lack of lubrication. A contributing factors was the lack of suitable terrain for the pilot to execute a forced landing.

Event Information

Type of Event Accident
Event Date 6/2/1998
Event Day of the Week Tuesday
Time of Event 1815
Event Time Zone Central Daylight Time
Event City DELAPLAINE
Event State ARKANSAS
Event Country --
Zipcode of the event site 72425
Event Date Year 1998
Event Date Month 6
MidAir Collision Indicator No
On Ground Collision occurred ? No
Event Location Latitude
Event Location Longitude
Event Location Airport
Event Location Nearest Airport ID
Indicates whether the acc/inc occurred off or on an airport Off Airport/Airstrip
Distance from airport in statute miles --
Degrees magnetic from airport --
Airport Elevation --
Weather Briefing Completeness Unknown
Investigator's weather source Weather Observation Facility
Time of the weather observation 1756 Central Daylight Time
Direction of event from weather observation facility (degrees) 225
Weather Observation Facility ID ARG
Elevation of weather observation facility 273
Distance of event from weather observation facility (units?) 12
Time Zone of the weather observation CDT
Lighting Conditions Day
Lowest Ceiling Height 0
Lowest Non-Ceiling Height 0
Sky/Lowest/Cloud Conditions Clear
Sky Condition for Lowest Ceiling None
Visibility Runway Visual Range (Feet) 0
Visibility Runway Visual Value (Statute Miles) 0
Visibility (Statute Miles) 10
Air Temperature at event time (in degrees celsius) 36
Dew Point at event time (in degress fahrenheit) 19
Wind Direction (degrees magnetic) 210
Variable Wind Indicator Unknown
Wind Speed (knots) 13
Wind Velocity Indicator Unknown
Wind Gust Indicator Not Gusting
Wind Gust (knots) 0
Altimeter Setting at event time (in. Hg) 29
Density Altitude (feet) 2650
Intensity of Precipitation Unknown
METAR weather report --
Event Highest Injury None
On Ground, Fatal Injuries 0
On Ground, Minor Injuries 0
On Ground, Serious Injuries 0
Injury Total Fatal --
Injury Total Minor --
Injury Total None 1
Injury Total Serious --
Injury Total All --
Investigating Agency NTSB
NTSB Docket Number (internal use) 738
NTSB Notification Source --
NTSB Notification Date Jun 3 1998 12:00AM
NTSB Notification Time 935
Fiche Number and/or location -used to find docket information IMAGE
Date of most recent change to record Dec 11 2000 11:32AM
User who most recently changed record dbo
Basic weather conditions Visual Meteorological Cond
FAA District Office --

Aircraft Involved

Aircraft #1

Aircraft Registration Number N4028T
NTSB Number FTW98LA253
Missing Aircraft Indicator N
Federal Aviation Reg. Part Part 137: Agricultural
Type of Flight Plan filed None
Flight plan Was Activated? --
Damage Substantial
Aircraft Fire None
Aircraft Explosion None
Aircraft Manufacturer's Full Name Hiller
Aircraft Model UH-12E
Aircraft Series Identifier UH-12E
Aircraft Serial Number 5097
Certified Max Gross Weight 3200
Aircraft Category Helicopter
Aircraft Registration Class U.S. Registered/U.S. Soil
Aircraft is a homebuilt? No
Flight Crew Seats --
Cabin Crew Seats --
Passenger Seats --
Total number of seats on the aircraft 3
Number of Engines 1
Fixed gear or retractable gear Fixed
Aircraft, Type of Last Inspection 100 Hour
Date of Last Inspection May 24 1998 12:00AM
Airframe hours since last inspection 25
Airframe Hours 2961
ELT Installed No
ELT Activated Unknown
ELT Aided Location of Event Site Unknown
ELT Type --
Aircraft Owner Name FRANK AND JUDY WILSON
Aircraft Owner Street Address P.O. BOX 862
Aircraft Owner City WALNUT RIDGE
Aircraft Owner State AR
Aircraft Owner Country
Aircraft Owner Zipcode 72476
Operator is an individual? --
Operator Name
Operator Same as Owner? Yes
Operator Is Doing Business As --
Operator Address Same as Owner? Yes
Operator Street Address
Operator City
Operator State
Operator Country
Operator Zip code
Operator Code ZHBG
Owner has at least one certificate Yes - certificate holder
Other Operator of large aircraft? No
Certified for Part 133 or 137 Operation Agriculture
Operator Certificate Number --
Indicates whether an air carrier operation was scheduled or not Unknown
Indicates Domestic or International Flight Unknown
Operator carrying Pax/Cargo/Mail Unknown
Type of Flying (Per_Bus / Primary) Aerial Application
Second Pilot on Board No
Departure Point Same as Event Yes
Departure Airport Code
Departure City
Departure State
Departure Country
Departure Time 1810
Departure Time Zone CDT
Destination Same as Local Flt dest & departure same, accident can occur anywhere
Destination Airport Code
Destination City
Destination State
Destination Country
Specific Phase of Flight Maneuvering
Report sent to ICAO? --
Evacuation occurred --
Date of most recent change to record Jan 2 2001 10:34AM
User who most recently changed record dbo
Since inspection or accident --
Event Location Runway Number and Location 0
Runway Length --
Runway Width --
Sight Seeing flight No
Air Medical Flight No
Medical Flight --