- Date
- September 1, 1992, 17:42 local (Sep 2, 1992, 01:42 UTC)
- Place
- Fort Yukon, AK
- Injuries
- 1 serious, 1 minor, 1 uninjured
- Damage
- Substantial damage
- Phase of flight
- Enroute
- Aircraft
- N8070ZCessna 206
- Weather
- Visual (VMC) · Day
- Status
- Completed · report December 16, 1993
- Report
- Approved by Office Director
- NTSB office
- Alaska Regional Office
- FAA report
- 19920901035009A
- Case key
- 5796
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
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.
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.
Analysis
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.
Aircraft
- Registration
- N8070Z
- Reported as
- Cessna 206
- Category
- Airplane
- Serial number
- U206-0470
- Engine
- Continental IO-520A, 285 horsepower, reciprocating
- Damage
- Substantial damage
- Flight
- Business · Part 91
- Operator
- Larry R. Rivers
- Registered owner
- Larry R. Rivers
- Airworthiness certificate
- Standard, Normal
- Last inspection
- Annual · January 2, 2000 · 35 hours before
- Departed
- Red Sheep Creek, AK
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
- 44
- Certificate
- Private
- Airplane ratings
- Single-engine sea, Single-engine land
- Medical
- Class 2, Valid Medical--no waivers/lim.
- Flight hours
- 4,900 total · 720 in this make and model · 4,830 as pilot in command · 155 in the last 90 days · 148 in the last 30 days · 5 in the last 24 hours
Weather
- Conditions
- Visual (VMC) · Day
- Visibility
- 50 statute miles
- Lowest ceiling
- 7,000 ft overcast
- Temperature
- 50 °F, dew point -0 °F
FAA reports on this event · 1
The FAA’s own accident and incident reports, matched to the aircraft by N-number and date.
Other investigations on N8070Z · 1
Matched to the same aircraft by N-number and date.