Wilhelms Airport
Aircraft Accident/Incident Report

Helena, Montana 59604
Saturday, April 17, 1993 17:30 MDT

NTSB Narrative Summary Released at Completion of Accident

THE PILOT FLEW A VFR TRAFFIC PATTERN FOR LANDING AT A FAMILIAR GRAVEL AIRSTRIP. THE ACFT STRUCK ELECTRICAL WIRES NEAR THE END OF THE STRIP DURING THE FINAL APPROACH, AND IMPACTED THE GROUND IN AN UNCONTROLLED DESCENT.

NTSB Probable Cause Narrative

THE INADEQUATE LOOKOUT BY THE PIC AND HIS FAILURE TO MAINTAIN CLEARANCE FROM ELECTRICAL WIRES. A FACTOR RELATING TO THE ACCIDENT WAS THE PRESENCE OF ELECTRICAL WIRES NEAR THE APPROACH END OF THE AIRSTRIP.

Event Information

Type of Event Accident
Event Date 4/17/1993
Event Day of the Week Saturday
Time of Event 1730
Event Time Zone Mountain Daylight Time
Event City HELENA
Event State MONTANA
Event Country --
Zipcode of the event site 59604
Event Date Year 1993
Event Date Month 4
MidAir Collision Indicator No
On Ground Collision occurred ? No
Event Location Latitude
Event Location Longitude
Event Location Airport WILHELMS
Event Location Nearest Airport ID NONE
Indicates whether the acc/inc occurred off or on an airport On Airport
Distance from airport in statute miles --
Degrees magnetic from airport --
Airport Elevation 4000
Weather Briefing Completeness Unknown
Investigator's weather source Weather Observation Facility
Time of the weather observation 1746 Mountain Daylight Time
Direction of event from weather observation facility (degrees) 135
Weather Observation Facility ID HLN
Elevation of weather observation facility 3873
Distance of event from weather observation facility (units?) 7
Time Zone of the weather observation MDT
Lighting Conditions Day
Lowest Ceiling Height 7500
Lowest Non-Ceiling Height 7500
Sky/Lowest/Cloud Conditions Unknown
Sky Condition for Lowest Ceiling Broken
Visibility Runway Visual Range (Feet) 0
Visibility Runway Visual Value (Statute Miles) 0
Visibility (Statute Miles) 40
Air Temperature at event time (in degrees celsius) 14
Dew Point at event time (in degress fahrenheit) -1
Wind Direction (degrees magnetic) 130
Variable Wind Indicator Unknown
Wind Speed (knots) 4
Wind Velocity Indicator Unknown
Wind Gust Indicator Unknown
Wind Gust (knots) 0
Altimeter Setting at event time (in. Hg) 29
Density Altitude (feet) 4160
Intensity of Precipitation Unknown
METAR weather report --
Event Highest Injury Minor
On Ground, Fatal Injuries 0
On Ground, Minor Injuries 0
On Ground, Serious Injuries 0
Injury Total Fatal --
Injury Total Minor 1
Injury Total None 1
Injury Total Serious --
Injury Total All 1
Investigating Agency NTSB
NTSB Docket Number (internal use) 425
NTSB Notification Source --
NTSB Notification Date Apr 17 1993 12:00AM
NTSB Notification Time 1710
Fiche Number and/or location -used to find docket information 51615
Date of most recent change to record Dec 11 2000 1:15PM
User who most recently changed record dbo
Basic weather conditions Visual Meteorological Cond
FAA District Office --

Aircraft Involved

Aircraft #1

Aircraft Registration Number N94142
NTSB Number SEA93LA098
Missing Aircraft Indicator N
Federal Aviation Reg. Part Part 91: General Aviation
Type of Flight Plan filed None
Flight plan Was Activated? --
Damage Destroyed
Aircraft Fire None
Aircraft Explosion None
Aircraft Manufacturer's Full Name Ercoupe (Eng & Research Corp.)
Aircraft Model 415-C
Aircraft Series Identifier 415-C
Aircraft Serial Number 1465
Certified Max Gross Weight 1260
Aircraft Category Airplane
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 2
Number of Engines 1
Fixed gear or retractable gear Fixed
Aircraft, Type of Last Inspection Annual
Date of Last Inspection Sep 14 1993 12:00AM
Airframe hours since last inspection --
Airframe Hours 1794
ELT Installed Yes
ELT Activated Unknown
ELT Aided Location of Event Site No
ELT Type --
Aircraft Owner Name WILHELM, CLAYTON D.
Aircraft Owner Street Address P.O. BOX 4474
Aircraft Owner City HELENA
Aircraft Owner State MT
Aircraft Owner Country
Aircraft Owner Zipcode 59604
Operator is an individual? --
Operator Name WILHELM, CLAYTON D.
Operator Same as Owner? Yes
Operator Is Doing Business As --
Operator Address Same as Owner? No
Operator Street Address P.O. BOX 4474
Operator City HELENA
Operator State MT
Operator Country
Operator Zip code 59604
Operator Code
Owner has at least one certificate None
Other Operator of large aircraft? No
Certified for Part 133 or 137 Operation Unknown
Operator Certificate Number --
Indicates whether an air carrier operation was scheduled or not --
Indicates Domestic or International Flight --
Operator carrying Pax/Cargo/Mail --
Type of Flying (Per_Bus / Primary) Personal
Second Pilot on Board No
Departure Point Same as Event Yes
Departure Airport Code
Departure City
Departure State
Departure Country
Departure Time 1630
Departure Time Zone MDT
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 Approach
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 36
Runway Length 5280
Runway Width 40
Sight Seeing flight No
Air Medical Flight No
Medical Flight --