Aircraft Accident/Incident Report

Fort Yukon, Alaska 99740
Tuesady, September 1, 1992 17:42 AKD

NTSB Narrative Summary Released at Completion of Accident

THE PILOT LOADED THE 2 PASSENGERS AND GEAR IN THE AIRPLANE TO THE EXTENT THAT IT TOOK SUCCESSIVE ATTEMPTS TO CLOSE THE DOOR DUE TO THE GEAR WHICH 'FILLED UP THE AIRPLANE TO THE ROOF.' THE REAR PAX HAD TO LAY ON TOP OF MEAT AND CAMP SUPPLIES WITH 2 DOGS IN HIS LAP. THE AIRPLANE WAS ESTIMATED TO BE 772 LBS OVER MAX GROSS WEIGHT AT TAKEOFF. AFTER TAKEOFF THE AIRPLANE CLIMBED SLOWLY FOR APRX 55 MIN AT TAKEOFF POWER. A 'SLEDGEHAMMER' SOUND PRECEDED THE APPEARANCE OF OIL FLOWING INTO THE CABIN AREA. NO REDUCTION OF POWER WAS OBSERVED. THE OIL PRESSURE BEGAN DROPPING RAPIDLY, AND THE PILOT MADE A PRECAUTIONARY LANDING ON A BEACH. THE AIRPLANE NOSED OVER IN GRASS. ENGINE TEARDOWN EXAMINATION REVEALED THAT THE #6 CYLINDER HAD FAILED THROUGH THE HEAD-TO-BARREL THREADED JOINT. METALLURGICAL EXAMINATION REVEALED THAT THE FAILURE WAS THE RESULT OF FATIGUE CRACKING IN THE CYLINDER HEAD CASTING. THIS TYPE OF FAILURE OCCURS WHEN THE CYLINDER IS OPERATED AT ELEVATED TEMPERATURES (ABOVE MAXIMUM ALLOWABLE) FOR A CONSIDERABLE PERIOD OF TIME.

NTSB Probable Cause Narrative

FATIGUE FAILURE OF AN ENGINE CYLINDER PRECIPITATED BY THE PILOT-IN-COMMAND INTENTIONALLY EXCEEDING THE ENGINE PERFORMANCE RATINGS IN ORDER TO SUSTAIN FLIGHT IN THE GROSSLY OVERWEIGHT CONDITION. A FACTOR CONTRIBUTING TO THE ACCIDENT WAS THE HIGH GRASS. A FACTOR CONTRIBUTING TO THE SEVERITY OF THE PASSENGER'S INJURY WAS THE UNSECURED CARGO.

Event Information

Type of Event Accident
Event Date 9/1/1992
Event Day of the Week Tuesday
Time of Event 1742
Event Time Zone --
Event City FORT YUKON
Event State ALASKA
Event Country --
Zipcode of the event site 99740
Event Date Year 1992
Event Date Month 9
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 --
Weather Briefing Completeness Unknown
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 7000
Lowest Non-Ceiling Height 0
Sky/Lowest/Cloud Conditions Unknown
Sky Condition for Lowest Ceiling Overcast
Visibility Runway Visual Range (Feet) 0
Visibility Runway Visual Value (Statute Miles) 0
Visibility (Statute Miles) 50
Air Temperature at event time (in degrees celsius) 10
Dew Point at event time (in degress fahrenheit) -18
Wind Direction (degrees magnetic) 0
Variable Wind Indicator Variable
Wind Speed (knots) 0
Wind Velocity Indicator Light and Variable
Wind Gust Indicator Unknown
Wind Gust (knots) 0
Altimeter Setting at event time (in. Hg) --
Density Altitude (feet) 0
Intensity of Precipitation Unknown
METAR weather report --
Event Highest Injury Serious
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 1
Injury Total All 2
Investigating Agency NTSB
NTSB Docket Number (internal use) 536
NTSB Notification Source --
NTSB Notification Date Sep 1 1992 12:00AM
NTSB Notification Time 1814
Fiche Number and/or location -used to find docket information 47861
Date of most recent change to record Dec 11 2000 3:17PM
User who most recently changed record dbo
Basic weather conditions Visual Meteorological Cond
FAA District Office --

Aircraft Involved

Aircraft #1

Aircraft Registration Number N8070Z
NTSB Number ANC92LA152
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 206
Aircraft Series Identifier 206
Aircraft Serial Number U206-0470
Certified Max Gross Weight 3600
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 Jan 2 2000 12:00AM
Airframe hours since last inspection 35
Airframe Hours --
ELT Installed Yes
ELT Activated Yes
ELT Aided Location of Event Site Yes
ELT Type --
Aircraft Owner Name LARRY R. RIVERS
Aircraft Owner Street Address BOX 507
Aircraft Owner City TALKEETNA
Aircraft Owner State AK
Aircraft Owner Country
Aircraft Owner Zipcode 99676
Operator is an individual? --
Operator Name LARRY R. RIVERS
Operator Same as Owner? Yes
Operator Is Doing Business As --
Operator Address Same as Owner? Yes
Operator Street Address BOX 507
Operator City TALKEETNA
Operator State AK
Operator Country
Operator Zip code 99676
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) Business
Second Pilot on Board Unknown
Departure Point Same as Event No
Departure Airport Code
Departure City RED SHEEP CREEK
Departure State AK
Departure Country
Departure Time 1435
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 Dec 11 2000 3:17PM
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 --