Individually Owned: 150,657
Corporate Owned: 137,281
Aircraft Accident/Incident Report
Quinhagak, Alaska 99559
Thursday, May 17, 2001 21:00 AKD
NTSB Narrative Summary Released at Completion of Accident
The certificated commercial pilot reported that during a flight earlier on the day of the incident, he had difficulty controlling the propeller rpm, so he elected to make a precautionary landing. The pilot related that after a mechanic replaced the propeller governor, the airplane's engine and governor appeared to be operating normally, so they began their flight back to the operator's base. He said that about 10 minutes after departure, while in cruise, level flight, he noted a light sheen of oil forming on the windshield, and he elected to make a precautionary landing on a remote beach. As he retarded the throttle to start the descent, the propeller rpm increased for about 20 seconds, followed by the propeller detaching from the engine. He said that he was able to glide the airplane to the beach, and land without further incident. The airplane was equipped with a Teledyne Continental Motors (TCM) IO-520-F engine. The propeller and engine crankshaft flange were eventually recovered, and sent to the NTSB metallurgical laboratory for examination. A Safety Board metallurgist examined the fractured crankshaft flange, and reported that his initial visual examination revealed a fatigue fracture, originating from a heat check site. A postincident investigation revealed that the engine crankshaft had been replaced by TCM, 94.3 hours before the crankshaft separation. An engine log book notation, entered by TCM, indicated that the reason for removal was: "...for compliance with CSB 99-3A." According to a representative from TCM's in-house analytical laboratory the crankshaft was a remanufactured part that reportedly was ground undersize, and re-nitrided at TCM. In the presence of an NTSB Investigator, the engine was disassembled. The investigator noted a significant amount of heat discoloration, with modest circumferential scoring of two forward most bearings, just aft of the fractured propeller shaft, indicating a localized loss of lubrication. He added that the oil transfer collar assembly was fractured in one location.
NTSB Probable Cause Narrative
An in-flight fracture of the engine crankshaft during descent, precipitated by restricted oil flow through an internal engine oil passage/port.
Event Information
| Type of Event | Incident |
| Event Date | 5/17/2001 |
| Event Day of the Week | Thursday |
| Time of Event | 2100 |
| Event Time Zone | -- |
| Event City | Quinhagak |
| Event State | ALASKA |
| Event Country | -- |
| Zipcode of the event site | 99559 |
| Event Date Year | 2001 |
| Event Date Month | 5 |
| MidAir Collision Indicator | No |
| On Ground Collision occurred ? | No |
| Event Location Latitude | 594100N |
| Event Location Longitude | 1615300W |
| 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 | Not pertinent |
| 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 | 6000 |
| Sky/Lowest/Cloud Conditions | Scattered |
| Sky Condition for Lowest Ceiling | None |
| Visibility Runway Visual Range (Feet) | -- |
| Visibility Runway Visual Value (Statute Miles) | -- |
| Visibility (Statute Miles) | 50 |
| Air Temperature at event time (in degrees celsius) | 12 |
| Dew Point at event time (in degress fahrenheit) | -- |
| Wind Direction (degrees magnetic) | -- |
| Variable Wind Indicator | Variable |
| Wind Speed (knots) | 10 |
| Wind Velocity Indicator | -- |
| Wind Gust Indicator | Not Gusting |
| 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) | 11387 |
| NTSB Notification Source | -- |
| NTSB Notification Date | May 17 2001 12:00AM |
| NTSB Notification Time | 2115 |
| Fiche Number and/or location -used to find docket information | IMAGE |
| Date of most recent change to record | Feb 20 2002 1:46PM |
| User who most recently changed record | NTSB\MONR |
| Basic weather conditions | Visual Meteorological Cond |
| FAA District Office | Anchorage FSDO |
Aircraft Involved |
|
|---|---|
Aircraft #1 |
|
| Aircraft Registration Number | N917AC |
| NTSB Number | ANC01IA058 |
| Missing Aircraft Indicator | -- |
| Federal Aviation Reg. Part | Part 91: General Aviation |
| Type of Flight Plan filed | Company VFR |
| Flight plan Was Activated? | Yes |
| Damage | Minor |
| Aircraft Fire | None |
| Aircraft Explosion | None |
| Aircraft Manufacturer's Full Name | Cessna |
| Aircraft Model | 207 |
| Aircraft Series Identifier | -- |
| Aircraft Serial Number | 20700517 |
| Certified Max Gross Weight | 3800 |
| 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 | 6 |
| Number of Engines | 1 |
| Fixed gear or retractable gear | Fixed |
| Aircraft, Type of Last Inspection | 100 Hour |
| Date of Last Inspection | Apr 2 2001 12:00AM |
| Airframe hours since last inspection | 45 |
| Airframe Hours | 6615 |
| ELT Installed | No |
| ELT Activated | No |
| ELT Aided Location of Event Site | No |
| ELT Type | -- |
| Aircraft Owner Name | Arctic Circle Air Service, Inc. |
| Aircraft Owner Street Address | P.O.Box 60049 |
| Aircraft Owner City | Fairbanks |
| Aircraft Owner State | AK |
| Aircraft Owner Country | USA |
| Aircraft Owner Zipcode | 99706 |
| Operator is an individual? | No |
| 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 | ACSA |
| Owner has at least one certificate | -- |
| Other Operator of large aircraft? | -- |
| Certified for Part 133 or 137 Operation | -- |
| 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) | Positioning |
| Second Pilot on Board | No |
| Departure Point Same as Event | No |
| Departure Airport Code | PTU |
| Departure City | PLATINUM |
| Departure State | AK |
| Departure Country | USA |
| Departure Time | 2045 |
| Departure Time Zone | ADT |
| Destination Same as Local Flt | -- |
| Destination Airport Code | BET |
| Destination City | BETHEL |
| Destination State | AK |
| Destination Country | USA |
| Specific Phase of Flight | Cruise - normal |
| Report sent to ICAO? | No |
| Evacuation occurred | No |
| Date of most recent change to record | Jan 29 2002 5:33PM |
| User who most recently changed record | STAM |
| Since inspection or accident | Time of Accident |
| Event Location Runway Number and Location | -- |
| Runway Length | -- |
| Runway Width | -- |
| Sight Seeing flight | No |
| Air Medical Flight | No |
| Medical Flight | -- |