Individually Owned: 150,657
Corporate Owned: 137,281
Tok Junction Airport
Aircraft Accident/Incident Report
Tok, Alaska 99505
Thursday, August 8, 2013 14:30 AKD
NTSB Narrative Summary Released at Completion of Accident
The pilot had just completed a water drop with a long-line and water bucket when he noticed a degradation of the helicopter’s directional control. He returned to the airport, released the bucket, and attempted a “stuck-pedal” run-on landing. During the attempted landing, the helicopter began to drift left toward trees. Unable to maintain directional control, the pilot initiated a go-around, and the main rotor blades then struck the treetops. After realigning with the runway, he executed a “slow-speed” run-on landing to a gravel area adjacent to the runway. During touchdown, the helicopter bounced multiple times, and it then came to rest upright. The helicopter sustained substantial damage to the fuselage, vertical fin, and tail rotor blades.
A postaccident examination of the tail rotor assembly revealed that the tail rotor crosshead bearing’s split inner ring’s inboard shoulder was spalled and completely worn away, which allowed the outboard set of bearing balls to run over the pitch change rod’s seating flange for the split inner ring’s inboard shoulder. The pitch change rod was then free to migrate outboard, and it machined a hole through the end of the crosshead. The movement of the pitch change rod decreased the effectiveness of the left antitorque pedal and increased the effectiveness of the right antitorque pedal.
NTSB Probable Cause Narrative
The failure of the tail rotor crosshead bearing, which resulted in a loss of tail rotor control.
Event Information
| Type of Event | Accident |
| Event Date | 8/8/2013 |
| Event Day of the Week | Thursday |
| Time of Event | 1430 |
| Event Time Zone | -- |
| Event City | Tok |
| Event State | ALASKA |
| Event Country | -- |
| Zipcode of the event site | 99505 |
| Event Date Year | 2013 |
| Event Date Month | 8 |
| MidAir Collision Indicator | No |
| On Ground Collision occurred ? | No |
| Event Location Latitude | 631928N |
| Event Location Longitude | 1425708W |
| Event Location Airport | Tok Junction |
| Event Location Nearest Airport ID | PFTO |
| 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 | 1639 |
| Weather Briefing Completeness | -- |
| Investigator's weather source | Weather Observation Facility |
| Time of the weather observation | 1453 AKD |
| Direction of event from weather observation facility (degrees) | 128 |
| Weather Observation Facility ID | PAOR |
| Elevation of weather observation facility | 1720 |
| Distance of event from weather observation facility (units?) | 36 |
| Time Zone of the weather observation | AKD |
| Lighting Conditions | Day |
| Lowest Ceiling Height | 11000 |
| Lowest Non-Ceiling Height | 5500 |
| Sky/Lowest/Cloud Conditions | Few |
| Sky Condition for Lowest Ceiling | Broken |
| 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) | 7 |
| Wind Direction (degrees magnetic) | 120 |
| Variable Wind Indicator | Wind direction could be determined |
| Wind Speed (knots) | 6 |
| Wind Velocity Indicator | -- |
| Wind Gust Indicator | Not Gusting |
| Wind Gust (knots) | -- |
| Altimeter Setting at event time (in. Hg) | 29.76 |
| 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) | 32877 |
| NTSB Notification Source | Alaskan FAA Regional Operation |
| NTSB Notification Date | -- |
| NTSB Notification Time | -- |
| Fiche Number and/or location -used to find docket information | -- |
| Date of most recent change to record | May 30 2014 8:09PM |
| User who most recently changed record | stam |
| Basic weather conditions | Visual Meteorological Cond |
| FAA District Office | -- |
Aircraft Involved |
|
|---|---|
Aircraft #1 |
|
| Aircraft Registration Number | N70NW |
| NTSB Number | ANC13TA076 |
| Missing Aircraft Indicator | -- |
| Federal Aviation Reg. Part | Part 133: Rotorcraft Ext. Load |
| 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 | BELL |
| Aircraft Model | UH-1B |
| Aircraft Series Identifier | -- |
| Aircraft Serial Number | 60-3568 |
| Certified Max Gross Weight | 8500 |
| Aircraft Category | Helicopter |
| Aircraft Registration Class | -- |
| 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 | Jul 27 2013 12:00AM |
| Airframe hours since last inspection | -- |
| Airframe Hours | 11144 |
| ELT Installed | Yes |
| ELT Activated | No |
| ELT Aided Location of Event Site | Unknown |
| ELT Type | C126 |
| Aircraft Owner Name | NORTHERN PIONEER HELICOPTERS LLC |
| Aircraft Owner Street Address | -- |
| Aircraft Owner City | BIG LAKE |
| Aircraft Owner State | AK |
| Aircraft Owner Country | USA |
| Aircraft Owner Zipcode | 99652-0670 |
| Operator is an individual? | No |
| Operator Name | NORTHERN PIONEER HELICOPTERS LLC |
| Operator Same as Owner? | Yes |
| Operator Is Doing Business As | -- |
| Operator Address Same as Owner? | Yes |
| Operator Street Address | -- |
| Operator City | BIG LAKE |
| Operator State | AK |
| Operator Country | USA |
| Operator Zip code | 99652-0670 |
| Operator Code | -- |
| Owner has at least one certificate | Yes - certificate holder |
| 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) | External Load |
| Second Pilot on Board | No |
| Departure Point Same as Event | Yes |
| Departure Airport Code | PFTO |
| Departure City | Tok |
| Departure State | AK |
| Departure Country | USA |
| Departure Time | 1340 |
| Departure Time Zone | AKD |
| Destination Same as Local Flt | crash at destination city |
| Destination Airport Code | PFTO |
| Destination City | Tok |
| Destination State | AK |
| Destination Country | USA |
| Specific Phase of Flight | -- |
| Report sent to ICAO? | -- |
| Evacuation occurred | -- |
| Date of most recent change to record | May 30 2014 8:10PM |
| User who most recently changed record | stam |
| Since inspection or accident | Time of Accident |
| Event Location Runway Number and Location | 25 |
| Runway Length | 2509 |
| Runway Width | 50 |
| Sight Seeing flight | No |
| Air Medical Flight | No |
| Medical Flight | -- |