Individually Owned: 150,657
Corporate Owned: 137,281
Bradley Sky Ranch Airport
Aircraft Accident/Incident Report
North Pole, Alaska 99705
Thursday, May 16, 2002 10:20 AKD
NTSB Narrative Summary Released at Completion of Accident
The right main landing gear leg separated from the airplane while landing on a gravel airstrip, which resulted in substantial damage to the airframe. The main landing gear had recently been rebuilt, and this was the second landing since the work was completed. The gear leg had been secured to the airplane with an AN7-20A bolt and an MS21044C stainless steel nut. The bolt, which remained attached to the separated gear leg was bent and the threads were damaged. The MS21044C nut had fractured, and was found in the right main landing gear bulkhead assembly. Examination of the nut determined it fractured due to circumferential overstress tension. The airplane manufacturer's parts catalog specifies a AN365-720C steel nut to secure the main landing gear legs. The military standard, under which the original AN365 nut was manufactured, requires any substitute nut to be of like material, plating, and thread size, and specifically excludes the substitution of the MS21044C nut in lieu of the AN365-720C nut. The proper substitute for the AN365-720C is the MS21044N, which is an all steel nut. However, the rated tensile strength of the AN365, MS21044C and MS21044N series nuts are all 125 ksi. Examination of the bolt revealed sheared threads adjacent to the bolt grip, indicating that the nut was intact on the bolt when the bolt/nut combination was loaded to failure. The bending deformation of the bolt indicated a side load was present during the failure. This side load could have resulted from a hard landing with the airplane moving sideways or improper reinstallation of the landing gear may have allowed normal landings to introduce side loads.
NTSB Probable Cause Narrative
The separation of the right main landing gear from the airplane during landing. A factor associated with the accident is the unapproved hardware used to attach the main landing gear.
Event Information
| Type of Event | Accident |
| Event Date | 5/16/2002 |
| Event Day of the Week | Thursday |
| Time of Event | 1020 |
| Event Time Zone | -- |
| Event City | North Pole |
| Event State | ALASKA |
| Event Country | -- |
| Zipcode of the event site | 99705 |
| Event Date Year | 2002 |
| Event Date Month | 5 |
| MidAir Collision Indicator | No |
| On Ground Collision occurred ? | No |
| Event Location Latitude | 644533N |
| Event Location Longitude | 1472316W |
| Event Location Airport | Bradley Sky Ranch |
| Event Location Nearest Airport ID | 95Z |
| Indicates whether the acc/inc occurred off or on an airport | On Airport |
| Distance from airport in statute miles | -- |
| Degrees magnetic from airport | -- |
| Airport Elevation | 483 |
| Weather Briefing Completeness | Unknown |
| 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) | 10 |
| Air Temperature at event time (in degrees celsius) | 21 |
| 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 | Not Gusting |
| Wind Gust (knots) | -- |
| Altimeter Setting at event time (in. Hg) | 29.91 |
| 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) | 14111 |
| NTSB Notification Source | FAA Fairbanks FSDO-1 |
| NTSB Notification Date | May 16 2002 12:00AM |
| NTSB Notification Time | 1039 |
| Fiche Number and/or location -used to find docket information | DMS |
| Date of most recent change to record | Nov 25 2003 11:36AM |
| User who most recently changed record | NTSB\MONR |
| Basic weather conditions | Visual Meteorological Cond |
| FAA District Office | Fairbanks FSDO-01 |
Aircraft Involved |
|
|---|---|
Aircraft #1 |
|
| Aircraft Registration Number | N4669C |
| NTSB Number | ANC02LA034 |
| Missing Aircraft Indicator | -- |
| Federal Aviation Reg. Part | Part 91: General Aviation |
| Type of Flight Plan filed | Unknown |
| Flight plan Was Activated? | No |
| Damage | Substantial |
| Aircraft Fire | None |
| Aircraft Explosion | None |
| Aircraft Manufacturer's Full Name | Cessna |
| Aircraft Model | 170B |
| Aircraft Series Identifier | -- |
| Aircraft Serial Number | 25613 |
| Certified Max Gross Weight | 2200 |
| 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 | 4 |
| Number of Engines | 1 |
| Fixed gear or retractable gear | Fixed |
| Aircraft, Type of Last Inspection | Annual |
| Date of Last Inspection | May 10 2002 12:00AM |
| Airframe hours since last inspection | 1 |
| Airframe Hours | 1262 |
| ELT Installed | Yes |
| ELT Activated | No |
| ELT Aided Location of Event Site | No |
| ELT Type | -- |
| Aircraft Owner Name | Kent E. Owen |
| Aircraft Owner Street Address | -- |
| Aircraft Owner City | North Pole |
| Aircraft Owner State | AK |
| Aircraft Owner Country | USA |
| Aircraft Owner Zipcode | 99711 |
| 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 | No |
| Departure Point Same as Event | No |
| Departure Airport Code | PAFA |
| Departure City | Fairbanks |
| Departure State | AK |
| Departure Country | USA |
| Departure Time | 931 |
| Departure Time Zone | ADT |
| Destination Same as Local Flt | crash at destination city |
| Destination Airport Code | 95Z |
| Destination City | North Pole |
| Destination State | AK |
| Destination Country | USA |
| Specific Phase of Flight | Landing - flare/touchdown |
| Report sent to ICAO? | No |
| Evacuation occurred | No |
| Date of most recent change to record | Aug 11 2003 6:52PM |
| User who most recently changed record | PETL |
| Since inspection or accident | Time of Accident |
| Event Location Runway Number and Location | 33 |
| Runway Length | 4093 |
| Runway Width | 80 |
| Sight Seeing flight | No |
| Air Medical Flight | No |
| Medical Flight | -- |