Individually Owned: 150,657
Corporate Owned: 137,281
Riverside Municipal Airport
Aircraft Accident/Incident Report
Riverside, California 92504
Thursday, July 5, 2001 17:01 PDT
NTSB Narrative Summary Released at Completion of Accident
The helicopter experienced a rough running engine on short final approach and entered an autorotation, but made a hard landing and sustained substantial damage. The crankshaft failed as the result of fatigue cracking initiated by surface damage and localized overheating. The crankshaft was reportedly overhauled 165 hours prior to the failure. Optical examinations of the fracture faces found beach marks and crack arrest lines indicative of fatigue cracking though the majority of the crank cheek. Further examinations established that the fatigue initiated at two origins on the aft radius surface of the No. 3 main bearing journal about halfway between the journal and cheek surfaces. An oil stain covered the aft radius and cleaning revealed wide spread surface damage to the radius. The presence of an oil stain on top of the damage indicates that the damage occurred either during the overhaul or soon there after and was not a result of the failure. The damage extended from the journal surface up to the level of the origin area and completely around the journal. The surface damage consisted of circumferential scoring, intermittent tearing, and material flow. The radius also had a slight bronze hue. Further cleaning and inspections found similar damage and coloration on the forward radius of the No. 3 main bearing but no damage to other journal radii. The direct visual examination of the No. 3 main bearing journal surface showed heavy circumferential scoring and roughening but no visual indications of overheating. The majority of the other journals, both rod and main, also displayed similar scoring but to lesser degrees. Measurements established that the diameters of all main bearing journals were between 2.238 and 2.240 inches. All rod journals measured 1.927 inches in diameter. Conversations with a distributor for new Franklin engines indicated that standard bearing sizes for 6A-335 engines are 2.250 to 2.249 inches for mains and 1.9375 to 1.9365 inches for rods. Bearings for 0.010- and 0.020-inch undersize journals are available for both the main and rod journals. The measurements on the fractured crankshaft are consistent with 0.010 inch under size journals for both the mains and rods. The presence of a white layer along with the undersized journals does indicate that the crankshaft had been renitrided at some point in time. The Franklin 6V-335 was originally certificated in 1956. The type certificate is now held by iyPZL-RzeszowlÈ (PZL) of Poland.
NTSB Probable Cause Narrative
The engine crankshaft's failure as the result of fatigue cracking initiated by surface damage and localized overheating due to the installation at overhaul of incorrectly sized bearings.
Event Information
| Type of Event | Accident |
| Event Date | 7/5/2001 |
| Event Day of the Week | Thursday |
| Time of Event | 1701 |
| Event Time Zone | Pacific Daylight Time |
| Event City | RIVERSIDE |
| Event State | CALIFORNIA |
| Event Country | -- |
| Zipcode of the event site | 92504 |
| Event Date Year | 2001 |
| Event Date Month | 7 |
| MidAir Collision Indicator | No |
| On Ground Collision occurred ? | No |
| Event Location Latitude | 335700N |
| Event Location Longitude | 1172700W |
| Event Location Airport | RIVERSIDE MUNICIPAL |
| Event Location Nearest Airport ID | RAL |
| Indicates whether the acc/inc occurred off or on an airport | On Airport |
| Distance from airport in statute miles | 0 |
| Degrees magnetic from airport | -- |
| Airport Elevation | 818 |
| Weather Briefing Completeness | Not pertinent |
| Investigator's weather source | Weather Observation Facility |
| Time of the weather observation | 1653 Pacific Daylight Time |
| Direction of event from weather observation facility (degrees) | -- |
| Weather Observation Facility ID | RAL |
| Elevation of weather observation facility | 818 |
| Distance of event from weather observation facility (units?) | 0 |
| Time Zone of the weather observation | PDT |
| Lighting Conditions | Day |
| Lowest Ceiling Height | 20000 |
| Lowest Non-Ceiling Height | -- |
| Sky/Lowest/Cloud Conditions | Clear |
| Sky Condition for Lowest Ceiling | Broken |
| Visibility Runway Visual Range (Feet) | -- |
| Visibility Runway Visual Value (Statute Miles) | -- |
| Visibility (Statute Miles) | 8 |
| Air Temperature at event time (in degrees celsius) | 33 |
| Dew Point at event time (in degress fahrenheit) | 18 |
| Wind Direction (degrees magnetic) | -- |
| Variable Wind Indicator | Variable |
| Wind Speed (knots) | 3 |
| Wind Velocity Indicator | -- |
| Wind Gust Indicator | Gusting |
| Wind Gust (knots) | 0 |
| Altimeter Setting at event time (in. Hg) | 29.85 |
| 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) | 14618 |
| NTSB Notification Source | FAA |
| NTSB Notification Date | Jul 5 2001 12:00AM |
| NTSB Notification Time | 1715 |
| Fiche Number and/or location -used to find docket information | DMS |
| Date of most recent change to record | Dec 30 2003 8:55AM |
| User who most recently changed record | NTSB\JOHB |
| Basic weather conditions | Visual Meteorological Cond |
| FAA District Office | WP-RAL-FSDO |
Aircraft Involved |
|
|---|---|
Aircraft #1 |
|
| Aircraft Registration Number | N64580 |
| NTSB Number | LAX01FA236 |
| Missing Aircraft Indicator | -- |
| Federal Aviation Reg. Part | Part 91: General Aviation |
| Type of Flight Plan filed | None |
| Flight plan Was Activated? | No |
| Damage | Substantial |
| Aircraft Fire | None |
| Aircraft Explosion | None |
| Aircraft Manufacturer's Full Name | Bell |
| Aircraft Model | 47D-1 |
| Aircraft Series Identifier | -- |
| Aircraft Serial Number | TWH-9 |
| Certified Max Gross Weight | 2350 |
| Aircraft Category | Helicopter |
| 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 | Jun 13 2001 12:00AM |
| Airframe hours since last inspection | 67 |
| Airframe Hours | 5283 |
| ELT Installed | No |
| ELT Activated | No |
| ELT Aided Location of Event Site | No |
| ELT Type | -- |
| Aircraft Owner Name | Michael Zemlock |
| Aircraft Owner Street Address | -- |
| Aircraft Owner City | Chino |
| Aircraft Owner State | CA |
| Aircraft Owner Country | USA |
| Aircraft Owner Zipcode | 91710 |
| 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 | -- |
| Owner has at least one certificate | None |
| 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) | Personal |
| Second Pilot on Board | Yes |
| Departure Point Same as Event | No |
| Departure Airport Code | CNO |
| Departure City | CHINO |
| Departure State | CA |
| Departure Country | USA |
| Departure Time | 1630 |
| Departure Time Zone | PDT |
| Destination Same as Local Flt | crash at destination city |
| Destination Airport Code | RAL |
| Destination City | RIVERSIDE |
| Destination State | CA |
| Destination Country | USA |
| Specific Phase of Flight | Landing |
| Report sent to ICAO? | Yes |
| Evacuation occurred | No |
| Date of most recent change to record | Oct 30 2003 6:28PM |
| User who most recently changed record | COOS |
| Since inspection or accident | Time of Accident |
| Event Location Runway Number and Location | 16 |
| Runway Length | 2851 |
| Runway Width | 48 |
| Sight Seeing flight | No |
| Air Medical Flight | No |
| Medical Flight | -- |