Aircraft Accident/Incident Report

Akiachak, Alaska 99551
Saturday, July 11, 2009 13:00 AKD

NTSB Narrative Summary Released at Completion of Accident

The airline transport pilot was on a Title 14, CFR Part 135 passenger flight. The pilot said during cruise flight he heard a loud bang, and the engine started running rough. He said he diverted to the nearest airport, but the engine quit completely, and he was unable to reach the runway. The airplane subsequently collided with terrain, sustaining substantial damage to both wings and the fuselage. An examination of the engine revealed that a locking screw had backed out of one of the anti-vibration counterweights on the crankshaft, scoring the interior back surface of the engine case. The unsecured counterweight then moved from its position in the crankshaft, and was likely struck by the engine's master rod, which shattered the weight, and liberated it from its normal location. The liberated counterweight was struck by internal moving parts, creating several component failures, and ultimately an engine seizure.

NTSB Probable Cause Narrative

The loss of engine power due to the failure of a crankshaft component, resulting in an off-airport landing.

Event Information

Type of Event Accident
Event Date 7/11/2009
Event Day of the Week Saturday
Time of Event 1300
Event Time Zone --
Event City Akiachak
Event State ALASKA
Event Country --
Zipcode of the event site 99551
Event Date Year 2009
Event Date Month 7
MidAir Collision Indicator No
On Ground Collision occurred ? No
Event Location Latitude 605421N
Event Location Longitude 1612535W
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 --
Investigator's weather source Pilot
Time of the weather observation
Direction of event from weather observation facility (degrees) --
Weather Observation Facility ID --
Elevation of weather observation facility --
Distance of event from weather observation facility (units?) --
Time Zone of the weather observation --
Lighting Conditions Day
Lowest Ceiling Height --
Lowest Non-Ceiling Height --
Sky/Lowest/Cloud Conditions Clear
Sky Condition for Lowest Ceiling None
Visibility Runway Visual Range (Feet) --
Visibility Runway Visual Value (Statute Miles) --
Visibility (Statute Miles) 40
Air Temperature at event time (in degrees celsius) 16
Dew Point at event time (in degress fahrenheit) --
Wind Direction (degrees magnetic) --
Variable Wind Indicator --
Wind Speed (knots) --
Wind Velocity Indicator Calm
Wind Gust Indicator --
Wind Gust (knots) --
Altimeter Setting at event time (in. Hg) --
Density Altitude (feet) --
Intensity of Precipitation --
METAR weather report --
Event Highest Injury None
On Ground, Fatal Injuries --
On Ground, Minor Injuries --
On Ground, Serious Injuries --
Injury Total Fatal --
Injury Total Minor --
Injury Total None 2
Injury Total Serious --
Injury Total All --
Investigating Agency NTSB
NTSB Docket Number (internal use) 26739
NTSB Notification Source FAA Anchorage, ROC
NTSB Notification Date --
NTSB Notification Time --
Fiche Number and/or location -used to find docket information --
Date of most recent change to record Apr 16 2010 4:07PM
User who most recently changed record johb
Basic weather conditions Visual Meteorological Cond
FAA District Office --

Aircraft Involved

Aircraft #1

Aircraft Registration Number N225BL
NTSB Number ANC09LA065
Missing Aircraft Indicator --
Federal Aviation Reg. Part Part 135: Air Taxi & Commuter
Type of Flight Plan filed Company VFR
Flight plan Was Activated? Yes
Damage Substantial
Aircraft Fire None
Aircraft Explosion None
Aircraft Manufacturer's Full Name NOORDUYN
Aircraft Model UC-64A
Aircraft Series Identifier --
Aircraft Serial Number 542
Certified Max Gross Weight 7540
Aircraft Category Airplane
Aircraft Registration Class --
Aircraft is a homebuilt? No
Flight Crew Seats --
Cabin Crew Seats --
Passenger Seats --
Total number of seats on the aircraft 9
Number of Engines 1
Fixed gear or retractable gear Fixed
Aircraft, Type of Last Inspection 100 Hour
Date of Last Inspection May 6 2009 12:00AM
Airframe hours since last inspection 20
Airframe Hours 15729
ELT Installed Yes
ELT Activated No
ELT Aided Location of Event Site No
ELT Type C91-A
Aircraft Owner Name RENFRO MICHAEL W
Aircraft Owner Street Address --
Aircraft Owner City BETHEL
Aircraft Owner State AK
Aircraft Owner Country USA
Aircraft Owner Zipcode 99559-0872
Operator is an individual? No
Operator Name RENFRO MICHAEL W
Operator Same as Owner? Yes
Operator Is Doing Business As --
Operator Address Same as Owner? Yes
Operator Street Address --
Operator City BETHEL
Operator State AK
Operator Country USA
Operator Zip code 99559-0872
Operator Code R59C
Owner has at least one certificate Yes - certificate holder
Other Operator of large aircraft? No
Certified for Part 133 or 137 Operation --
Operator Certificate Number R59C987K
Indicates whether an air carrier operation was scheduled or not Non-scheduled
Indicates Domestic or International Flight Domestic
Operator carrying Pax/Cargo/Mail Passenger Only
Type of Flying (Per_Bus / Primary) --
Second Pilot on Board No
Departure Point Same as Event No
Departure Airport Code PABE
Departure City Bethel
Departure State AK
Departure Country USA
Departure Time 1200
Departure Time Zone AST
Destination Same as Local Flt --
Destination Airport Code TLT
Destination City Tuluksak
Destination State AK
Destination Country USA
Specific Phase of Flight --
Report sent to ICAO? --
Evacuation occurred --
Date of most recent change to record Mar 26 2010 7:43PM
User who most recently changed record stam
Since inspection or accident Time of Accident
Event Location Runway Number and Location N/A
Runway Length --
Runway Width --
Sight Seeing flight No
Air Medical Flight No
Medical Flight --