Aircraft Accident/Incident Report

Trinity Lake, Alaska
Tuesady, April 11, 1989 17:30 AKD

NTSB Narrative Summary Released at Completion of Accident

THE PILOT WAS ATTEMPTING A LATE AFTERNOON LANDING AT AN OFF AIRPORT LANDING SITE ON A SNOW COVERED LAKE. SHORTLY AFTER TOUCH DOWN, THE RIGHT MAIN LANDING GEAR SKI BECAME DETACHED FROM THE GEAR LEG. THE GEAR LEG WENT THROUGH THE SNOW AND INTO THE ICE BELOW, COLLAPSING THE RIGHT MAIN GEAR IN THE PROCESS. THE PILOT REPORTED THAT THE SNOW CONDITIONS WERE EXTREMELY WET, AND THAT DURING THE LANDING ROLL THE RIGHT MAIN SKI BECAME MIRED IN THE HEAVY SNOW, ULTIMATELY CAUSING THE SKI ATTACHMENT BOLTS TO FAIL AND ALLOWING THE GEAR LEG TO STRIKE THE ICE.

NTSB Probable Cause Narrative

THE PILOT'S SELECTION OF UNSUITABLE TERRAIN ON WHICH TO LAND.

Event Information

Type of Event Accident
Event Date 4/11/1989
Event Day of the Week Tuesday
Time of Event 1730
Event Time Zone --
Event City TRINITY LAKE
Event State ALASKA
Event Country --
Zipcode of the event site
Event Date Year 1989
Event Date Month 4
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 0
Degrees magnetic from airport 0
Airport Elevation 850
Weather Briefing Completeness Not pertinent
Investigator's weather source Pilot
Time of the weather observation 0
Direction of event from weather observation facility (degrees) 0
Weather Observation Facility ID
Elevation of weather observation facility 0
Distance of event from weather observation facility (units?) 0
Time Zone of the weather observation
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) 60
Air Temperature at event time (in degrees celsius) 4
Dew Point at event time (in degress fahrenheit) --
Wind Direction (degrees magnetic) 360
Variable Wind Indicator Unknown
Wind Speed (knots) 5
Wind Velocity Indicator Unknown
Wind Gust Indicator Not Gusting
Wind Gust (knots) 0
Altimeter Setting at event time (in. Hg) --
Density Altitude (feet) --
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 2
Injury Total Serious --
Injury Total All --
Investigating Agency NTSB
NTSB Docket Number (internal use) 62
NTSB Notification Source --
NTSB Notification Date --
NTSB Notification Time 0
Fiche Number and/or location -used to find docket information 38039
Date of most recent change to record Mar 17 2006 2:54PM
User who most recently changed record NTSB\ZUZL
Basic weather conditions Visual Meteorological Cond
FAA District Office --

Aircraft Involved

Aircraft #1

Aircraft Registration Number N9850X
NTSB Number ANC89LA058
Missing Aircraft Indicator N
Federal Aviation Reg. Part Part 91: General Aviation
Type of Flight Plan filed None
Flight plan Was Activated? --
Damage Substantial
Aircraft Fire None
Aircraft Explosion None
Aircraft Manufacturer's Full Name CESSNA
Aircraft Model 185
Aircraft Series Identifier 185
Aircraft Serial Number 1850050
Certified Max Gross Weight 3350
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 4
Number of Engines 1
Fixed gear or retractable gear Fixed
Aircraft, Type of Last Inspection Annual
Date of Last Inspection Jun 13 1988 12:00AM
Airframe hours since last inspection 97
Airframe Hours 3881
ELT Installed Yes
ELT Activated No
ELT Aided Location of Event Site No
ELT Type --
Aircraft Owner Name COSTLEY, DONALD E.
Aircraft Owner Street Address 6425 TOLHURST CT.
Aircraft Owner City ANCHORAGE
Aircraft Owner State AK
Aircraft Owner Country
Aircraft Owner Zipcode 99504
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
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 No
Departure Airport Code LHD
Departure City ANCHORAGE
Departure State AK
Departure Country
Departure Time 1700
Departure Time Zone ADT
Destination Same as Local Flt crash at destination city
Destination Airport Code
Destination City
Destination State
Destination Country
Specific Phase of Flight Landing
Report sent to ICAO? --
Evacuation occurred --
Date of most recent change to record Jan 2 2001 10:35AM
User who most recently changed record dbo
Since inspection or accident --
Event Location Runway Number and Location 0
Runway Length 0
Runway Width 0
Sight Seeing flight No
Air Medical Flight No
Medical Flight --