Narrative:
A DHC-3T Texas Turbine Otter, experienced an anomalous in-flight vibration during cruise flight in the vicinity of Skwentna, Alaska. The airline transport pilot was not injured, and the airplane sustained substantial damage to the right elevator. Instrument meteorological conditions prevailed in the area. The flight departed Anchorage, Alaska about 1200, enroute to an off-airport landing strip near Big River, Alaska.
According to the pilot, during cruise flight, while applying back pressure to the control yoke, a vibration was felt. The pilot immediately reduced power and executed a precautionary landing. After landing, the pilot examined the airplane and found that the skin on the right elevator servo tab was fractured and separated from the hinge, and spar structures inside the right elevator were cracked.
The elevator skin, elevator servo skin and hinge were retained for further examination.
This same aircraft, N3125N, was involved in an accident on 30 May 2014, when during cruise flight, the airplane vibrated and subsequently pitched nose-down. After landing it was found that the skin on the right elevator servo tab was separated from the hinge, and spar structures inside the right elevator were cracked.
PROBABLE CAUSE: "The flutter failure of the right elevator servo tab due to the improper fabrication of the servo tab and maintenance personnels subsequent failure to detect anomalies with the servo tab."
Elevator issue
Forced landing on runway
| Status: | Accident investigation report completed and information captured |
| Date: | Thursday 4 June 2015 |
| Time: | 12:30 |
| Type: |  de Havilland Canada DHC-3T Texas Turbine Otter |
| Operator: | Alaska Air Taxi |
| Registration: | N3125N |
| MSN: | 394 |
| First flight: | 1960 |
| Engines: | 1 Garrett TPE331 |
| Crew: | Fatalities: 0 / Occupants: 1 |
| Passengers: | Fatalities: 0 / Occupants: 0 |
| Total: | Fatalities: 0 / Occupants: 1 |
| Aircraft damage: | Substantial |
| Location: | near Skwentna, AK ( United States of America)
|
| Phase: | En route (ENR) |
| Nature: | Cargo |
| Departure airport: | Anchorage-Ted Stevens International Airport, AK (ANC/PANC), United States of America |
| ? |
A DHC-3T Texas Turbine Otter, experienced an anomalous in-flight vibration during cruise flight in the vicinity of Skwentna, Alaska. The airline transport pilot was not injured, and the airplane sustained substantial damage to the right elevator. Instrument meteorological conditions prevailed in the area. The flight departed Anchorage, Alaska about 1200, enroute to an off-airport landing strip near Big River, Alaska.
According to the pilot, during cruise flight, while applying back pressure to the control yoke, a vibration was felt. The pilot immediately reduced power and executed a precautionary landing. After landing, the pilot examined the airplane and found that the skin on the right elevator servo tab was fractured and separated from the hinge, and spar structures inside the right elevator were cracked.
The elevator skin, elevator servo skin and hinge were retained for further examination.
This same aircraft, N3125N, was involved in an accident on 30 May 2014, when during cruise flight, the airplane vibrated and subsequently pitched nose-down. After landing it was found that the skin on the right elevator servo tab was separated from the hinge, and spar structures inside the right elevator were cracked.
Probable Cause:
PROBABLE CAUSE: "The flutter failure of the right elevator servo tab due to the improper fabrication of the servo tab and maintenance personnels subsequent failure to detect anomalies with the servo tab."
Classification:
Elevator issue
Forced landing on runway
Sources:
» NTSBPhotos
This information is not presented as the Flight Safety Foundation or the Aviation Safety Network’s opinion as to the cause of the accident. It is preliminary and is based on the facts as they are known at this time.
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