Individually Owned: 150,657
Corporate Owned: 137,281
Aircraft Accident/Incident Report
Skwentna, Alaska 99667
Saturday, July 25, 1998 14:00 AKD
NTSB Narrative Summary Released at Completion of Accident
The certificated commercial helicopter pilot was conducting a salmon survey for the State of Alaska, Department of Fish & Game. This operation required him to hover the helicopter over the stream while the passenger, a wildlife biologist employed by the State of Alaska, noted the number of fish. The pilot stated that while in a hover above the stream, he felt a slight vibration followed by a partial loss of engine power. He said that while hover taxiing the helicopter to a suitable landing area, the engine continued to lose power, and he was forced to make a downwind autorotation. He said that as the helicopter touched down, the main rotor blades flexed downward, and struck the tail boom. The helicopter's tail boom, and tail rotor gearbox sustained substantial damage. The operator reported that during a postaccident inspection of the engine, a fractured intake manifold flange was discovered on the number three cylinder assembly.
NTSB Probable Cause Narrative
A loss of engine power due to a fractured number three cylinder intake manifold flange, and the pilot's inability to maintain the proper rate of descent during the autorotation flare. A contributing factor associated with the accident was the downwind (tailwind) landing condition.
Event Information
| Type of Event | Accident |
| Event Date | 7/25/1998 |
| Event Day of the Week | Saturday |
| Time of Event | 1400 |
| Event Time Zone | -- |
| Event City | SKWENTNA |
| Event State | ALASKA |
| Event Country | -- |
| Zipcode of the event site | 99667 |
| Event Date Year | 1998 |
| Event Date Month | 7 |
| MidAir Collision Indicator | No |
| On Ground Collision occurred ? | No |
| Event Location Latitude | |
| Event Location Longitude | |
| 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 | Unknown |
| Investigator's weather source | Pilot |
| Time of the weather observation | 0 |
| Direction of event from weather observation facility (degrees) | 0 |
| Weather Observation Facility ID | |
| Elevation of weather observation facility | 0 |
| Distance of event from weather observation facility (units?) | 0 |
| Time Zone of the weather observation | |
| Lighting Conditions | Day |
| Lowest Ceiling Height | 1500 |
| Lowest Non-Ceiling Height | 0 |
| Sky/Lowest/Cloud Conditions | Unknown |
| Sky Condition for Lowest Ceiling | Overcast |
| Visibility Runway Visual Range (Feet) | 0 |
| Visibility Runway Visual Value (Statute Miles) | 0 |
| Visibility (Statute Miles) | 7 |
| Air Temperature at event time (in degrees celsius) | 13 |
| Dew Point at event time (in degress fahrenheit) | -- |
| Wind Direction (degrees magnetic) | 120 |
| Variable Wind Indicator | Unknown |
| Wind Speed (knots) | 10 |
| Wind Velocity Indicator | Unknown |
| Wind Gust Indicator | Unknown |
| Wind Gust (knots) | 15 |
| Altimeter Setting at event time (in. Hg) | -- |
| Density Altitude (feet) | -- |
| Intensity of Precipitation | Light |
| METAR weather report | -- |
| Event Highest Injury | None |
| On Ground, Fatal Injuries | 0 |
| On Ground, Minor Injuries | 0 |
| On Ground, Serious Injuries | 0 |
| Injury Total Fatal | -- |
| Injury Total Minor | -- |
| Injury Total None | 2 |
| Injury Total Serious | -- |
| Injury Total All | -- |
| Investigating Agency | NTSB |
| NTSB Docket Number (internal use) | 876 |
| NTSB Notification Source | -- |
| NTSB Notification Date | Jul 25 1998 12:00AM |
| NTSB Notification Time | 1638 |
| Fiche Number and/or location -used to find docket information | IMAGE |
| Date of most recent change to record | Dec 11 2000 11:35AM |
| User who most recently changed record | dbo |
| Basic weather conditions | Visual Meteorological Cond |
| FAA District Office | -- |
Aircraft Involved |
|
|---|---|
Aircraft #1 |
|
| Aircraft Registration Number | N8622U |
| NTSB Number | ANC98LA109 |
| Missing Aircraft Indicator | N |
| Federal Aviation Reg. Part | Part 135: Air Taxi & Commuter |
| Type of Flight Plan filed | Company VFR |
| Flight plan Was Activated? | -- |
| Damage | Substantial |
| Aircraft Fire | None |
| Aircraft Explosion | None |
| Aircraft Manufacturer's Full Name | Enstrom |
| Aircraft Model | F-28F |
| Aircraft Series Identifier | F-28F |
| Aircraft Serial Number | 721 |
| Certified Max Gross Weight | 2600 |
| 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 | 3 |
| Number of Engines | 1 |
| Fixed gear or retractable gear | Fixed |
| Aircraft, Type of Last Inspection | Annual |
| Date of Last Inspection | Feb 28 1998 12:00AM |
| Airframe hours since last inspection | 74 |
| Airframe Hours | 1280 |
| ELT Installed | Yes |
| ELT Activated | Yes |
| ELT Aided Location of Event Site | No |
| ELT Type | -- |
| Aircraft Owner Name | MARK E. MILLER |
| Aircraft Owner Street Address | P.O. BOX 190043 |
| Aircraft Owner City | ANCHORAGE |
| Aircraft Owner State | AK |
| Aircraft Owner Country | |
| Aircraft Owner Zipcode | 99515 |
| Operator is an individual? | -- |
| 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 | EMVC |
| Owner has at least one certificate | Yes - certificate holder |
| Other Operator of large aircraft? | No |
| Certified for Part 133 or 137 Operation | Unknown |
| Operator Certificate Number | -- |
| Indicates whether an air carrier operation was scheduled or not | Non-scheduled |
| Indicates Domestic or International Flight | Domestic |
| Operator carrying Pax/Cargo/Mail | Passenger Only |
| Type of Flying (Per_Bus / Primary) | Unknown |
| Second Pilot on Board | No |
| Departure Point Same as Event | Yes |
| Departure Airport Code | SKW |
| Departure City | |
| Departure State | AK |
| Departure Country | |
| Departure Time | 1245 |
| Departure Time Zone | ADT |
| Destination Same as Local Flt | dest & departure same, accident can occur anywhere |
| Destination Airport Code | |
| Destination City | |
| Destination State | |
| Destination Country | |
| Specific Phase of Flight | Hover |
| Report sent to ICAO? | -- |
| Evacuation occurred | -- |
| Date of most recent change to record | Jan 2 2001 10:34AM |
| User who most recently changed record | dbo |
| Since inspection or accident | -- |
| Event Location Runway Number and Location | 0 |
| Runway Length | -- |
| Runway Width | -- |
| Sight Seeing flight | No |
| Air Medical Flight | No |
| Medical Flight | -- |