Individually Owned: 150,657
Corporate Owned: 137,281
San Luis County Airport
Aircraft Accident/Incident Report
San Luis Obispo, California 93401
Thursday, January 20, 2011 13:17 PST
NTSB Narrative Summary Released at Completion of Accident
The pilot reported that, while on approach to the runway, the vacuum pump failed, then the engine lost power. The pilot initiated a forced landing to a field, and the airplane impacted multiple metal poles. Postaccident examination of the engine revealed that the left magneto drive gear and the left idler gear shaft were separated from their mount. Both of the attachment bolts for the left idler gear shaft were separated from the crankcase, and their respective bolt bores were elongated. One of the attachment bolts for the left idler gear shaft was fractured, and metallurgical examination revealed that the fracture surface was consistent with fatigue. Metallurgical analysis determined that the fatigue was due to a lack of sufficient preload on the bolts. Maintenance records showed that the last logged maintenance activity in which the bolts could have been manipulated was performed about 20 years before the accident. The engine had accumulated about 1,400 operating hours since that time.
NTSB Probable Cause Narrative
The loss of engine power due to the fatigue fracture of one attachment bolt for the left idler gear shaft, which resulted from an insufficient preload on both attachment bolts.
Event Information
| Type of Event | Accident |
| Event Date | 1/20/2011 |
| Event Day of the Week | Thursday |
| Time of Event | 1317 |
| Event Time Zone | Pacific Standard Time |
| Event City | San Luis Obispo |
| Event State | CALIFORNIA |
| Event Country | -- |
| Zipcode of the event site | 93401 |
| Event Date Year | 2011 |
| Event Date Month | 1 |
| MidAir Collision Indicator | No |
| On Ground Collision occurred ? | No |
| Event Location Latitude | 351414N |
| Event Location Longitude | 1203033W |
| Event Location Airport | San Luis County Airport |
| Event Location Nearest Airport ID | SBP |
| Indicates whether the acc/inc occurred off or on an airport | Off Airport/Airstrip |
| Distance from airport in statute miles | 1 |
| Degrees magnetic from airport | -- |
| Airport Elevation | 212 |
| Weather Briefing Completeness | -- |
| Investigator's weather source | Weather Observation Facility |
| Time of the weather observation | 1256 Pacific Standard Time |
| Direction of event from weather observation facility (degrees) | 290 |
| Weather Observation Facility ID | SBP |
| Elevation of weather observation facility | 212 |
| Distance of event from weather observation facility (units?) | 1 |
| Time Zone of the weather observation | PST |
| 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) | 10 |
| Air Temperature at event time (in degrees celsius) | 22 |
| Dew Point at event time (in degress fahrenheit) | 7 |
| Wind Direction (degrees magnetic) | -- |
| Variable Wind Indicator | Variable |
| Wind Speed (knots) | 4 |
| Wind Velocity Indicator | -- |
| Wind Gust Indicator | Not Gusting |
| Wind Gust (knots) | -- |
| Altimeter Setting at event time (in. Hg) | 30.08 |
| 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 | 1 |
| Injury Total Serious | -- |
| Injury Total All | -- |
| Investigating Agency | NTSB |
| NTSB Docket Number (internal use) | 29329 |
| NTSB Notification Source | FAA Operations Center |
| NTSB Notification Date | -- |
| NTSB Notification Time | -- |
| Fiche Number and/or location -used to find docket information | -- |
| Date of most recent change to record | Nov 28 2011 4:40PM |
| User who most recently changed record | stam |
| Basic weather conditions | Visual Meteorological Cond |
| FAA District Office | -- |
Aircraft Involved |
|
|---|---|
Aircraft #1 |
|
| Aircraft Registration Number | N8608W |
| NTSB Number | WPR11LA102 |
| Missing Aircraft Indicator | -- |
| 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 | PIPER |
| Aircraft Model | PA-28-235 |
| Aircraft Series Identifier | -- |
| Aircraft Serial Number | 28-10124 |
| Certified Max Gross Weight | 2900 |
| 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 | 4 |
| Number of Engines | 1 |
| Fixed gear or retractable gear | Retractable |
| Aircraft, Type of Last Inspection | Annual |
| Date of Last Inspection | Mar 23 2010 12:00AM |
| Airframe hours since last inspection | 46 |
| Airframe Hours | 3505 |
| ELT Installed | Yes |
| ELT Activated | No |
| ELT Aided Location of Event Site | No |
| ELT Type | Unknown |
| Aircraft Owner Name | ELLIOTT CLIFFORD R TRUSTEE |
| Aircraft Owner Street Address | -- |
| Aircraft Owner City | SAN LUIS OBISPO |
| Aircraft Owner State | CA |
| Aircraft Owner Country | USA |
| Aircraft Owner Zipcode | 93401-8257 |
| Operator is an individual? | No |
| Operator Name | ELLIOTT CLIFFORD R TRUSTEE |
| Operator Same as Owner? | Yes |
| Operator Is Doing Business As | -- |
| Operator Address Same as Owner? | Yes |
| Operator Street Address | -- |
| Operator City | SAN LUIS OBISPO |
| Operator State | CA |
| Operator Country | USA |
| Operator Zip code | 93401-8257 |
| Operator Code | -- |
| Owner has at least one certificate | None |
| Other Operator of large aircraft? | No |
| 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) | Personal |
| Second Pilot on Board | No |
| Departure Point Same as Event | Yes |
| Departure Airport Code | SBP |
| Departure City | San Luis Obispo |
| Departure State | CA |
| Departure Country | USA |
| Departure Time | 1130 |
| Departure Time Zone | PST |
| Destination Same as Local Flt | dest & departure same, accident can occur anywhere |
| Destination Airport Code | SBP |
| Destination City | San Luis Obispo |
| Destination State | CA |
| Destination Country | USA |
| Specific Phase of Flight | -- |
| Report sent to ICAO? | -- |
| Evacuation occurred | -- |
| Date of most recent change to record | Nov 28 2011 4:31PM |
| User who most recently changed record | stam |
| Since inspection or accident | Last Inspection |
| Event Location Runway Number and Location | N/A |
| Runway Length | -- |
| Runway Width | -- |
| Sight Seeing flight | No |
| Air Medical Flight | No |
| Medical Flight | -- |