Individually Owned: 150,657
Corporate Owned: 137,281
Aircraft Accident/Incident Report
Talkeetna, Alaska 99676
Monday, March 7, 2005 11:00 AST
NTSB Narrative Summary Released at Completion of Accident
The airline transport pilot was conducting a mountain sightseeing flight with three passengers under Title 14, CFR Part 135. The pilot said the flight was at 11,000 feet msl and encountering some turbulence, when the airplane started to shake violently. He said he could not control the airplane, and stopped the engine in case it was creating the problem. The shaking continued until he slowed the airplane to 80 mph. He restarted the engine, and landed safely. An examination of the airplane revealed that both wings were structurally damaged. Prior to the event, the pilot had been taking a digital video with audio through the window of the airplane. The recording shows the airplane in a wings level attitude in VFR conditions. When dropped to the floor after the initiation of the event, the camera continued to record. The audio recording revealed a vibration for about 3 to 7 seconds in the 8.2 to 8.4 Hz range, which is in the appropriate range for the wing bending/torsional first mode of vibration. Nothing on the visual or audio recording indicated the airplane was being flown outside its normal operating envelope. The airplane was examined by aerospace engineers from the Anchorage FAA Aircraft Certification Office. Damage signatures indicated that the rear spars of both wings oscillated up and down with significant amplitude at span station 92.5. The bushing holes in the rear spar attachment fittings were elongated, and the right aileron and rudder were severely under-balanced. The engineers were not able to ascertain if the aileron cable tension was adjusted properly prior to the event. In 1980, prompted by flutter events, the manufacturer produced Service Bulletin 2/29, relating aileron/wing flutter to more than one of the following four conditions: ailerons not balanced; aileron cables in the wing slack; deterioration in the stiffness of the aileron mounting structure in the fuselage; and/or the airplane being flown outside the limits of the flight manual. On February 20, 1980, in response to the manufacturer's service bulletin, the FAA issued Airworthiness Directive AD 80-24-02, which required inspections of the airplane's wings, spars, and aileron cable tension and balance, based on service time and part numbers.
NTSB Probable Cause Narrative
Aerodynamic flutter of the ailerons during normal cruise flight due to their improper maintenance/balancing, which resulted in structural damage to the airplane's wings.
Event Information
| Type of Event | Accident |
| Event Date | 3/7/2005 |
| Event Day of the Week | Monday |
| Time of Event | 1100 |
| Event Time Zone | Atlantic Standard Time |
| Event City | Talkeetna |
| Event State | ALASKA |
| Event Country | -- |
| Zipcode of the event site | 99676 |
| Event Date Year | 2005 |
| Event Date Month | 3 |
| MidAir Collision Indicator | No |
| On Ground Collision occurred ? | No |
| Event Location Latitude | 631730N |
| Event Location Longitude | 1500530W |
| 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 | -- |
| 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) | -7 |
| Dew Point at event time (in degress fahrenheit) | -- |
| Wind Direction (degrees magnetic) | -- |
| Variable Wind Indicator | -- |
| Wind Speed (knots) | -- |
| Wind Velocity Indicator | -- |
| Wind Gust Indicator | Unknown |
| Wind Gust (knots) | -- |
| Altimeter Setting at event time (in. Hg) | -- |
| 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 | 4 |
| Injury Total Serious | -- |
| Injury Total All | -- |
| Investigating Agency | NTSB |
| NTSB Docket Number (internal use) | 19785 |
| NTSB Notification Source | Pilot |
| NTSB Notification Date | Mar 7 2005 12:00AM |
| NTSB Notification Time | 1400 |
| Fiche Number and/or location -used to find docket information | DMS |
| Date of most recent change to record | Jun 28 2006 1:30PM |
| User who most recently changed record | NTSB\JOHB |
| Basic weather conditions | Visual Meteorological Cond |
| FAA District Office | Anchorage, FSDO-03 |
Aircraft Involved |
|
|---|---|
Aircraft #1 |
|
| Aircraft Registration Number | N3307S |
| NTSB Number | ANC05LA046 |
| Missing Aircraft Indicator | -- |
| 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 | de Havilland |
| Aircraft Model | DHC-2 |
| Aircraft Series Identifier | -- |
| Aircraft Serial Number | 1092 |
| Certified Max Gross Weight | 5115 |
| 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 | 7 |
| Number of Engines | 1 |
| Fixed gear or retractable gear | Fixed |
| Aircraft, Type of Last Inspection | 100 Hour |
| Date of Last Inspection | -- |
| Airframe hours since last inspection | -- |
| Airframe Hours | 9768 |
| ELT Installed | Yes |
| ELT Activated | No |
| ELT Aided Location of Event Site | No |
| ELT Type | -- |
| Aircraft Owner Name | James J. Trumbull |
| Aircraft Owner Street Address | -- |
| Aircraft Owner City | Denali Park |
| Aircraft Owner State | AK |
| Aircraft Owner Country | USA |
| Aircraft Owner Zipcode | 99755 |
| Operator is an individual? | No |
| Operator Name | Fly Denali, Inc. |
| Operator Same as Owner? | No |
| Operator Is Doing Business As | -- |
| Operator Address Same as Owner? | No |
| Operator Street Address | -- |
| Operator City | Talkeetna |
| Operator State | AK |
| Operator Country | USA |
| Operator Zip code | 99676 |
| Operator Code | A3WC |
| Owner has at least one certificate | -- |
| 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 | Non-scheduled |
| Indicates Domestic or International Flight | Domestic |
| Operator carrying Pax/Cargo/Mail | Passenger Only |
| Type of Flying (Per_Bus / Primary) | -- |
| Second Pilot on Board | No |
| Departure Point Same as Event | No |
| Departure Airport Code | TKA |
| Departure City | Talkeetna |
| Departure State | AK |
| Departure Country | USA |
| Departure Time | 1130 |
| Departure Time Zone | AST |
| 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 | Cruise - normal |
| Report sent to ICAO? | Yes |
| Evacuation occurred | No |
| Date of most recent change to record | Apr 5 2006 3:26PM |
| User who most recently changed record | STAM |
| Since inspection or accident | Last Inspection |
| Event Location Runway Number and Location | NA |
| Runway Length | -- |
| Runway Width | -- |
| Sight Seeing flight | Yes |
| Air Medical Flight | No |
| Medical Flight | -- |