ASN Wikibase Occurrence # 214678
This information is added by users of ASN. Neither ASN nor the Flight Safety Foundation are responsible for the completeness or correctness of this information.
If you feel this information is incomplete or incorrect, you can submit corrected information.
| Date: | Saturday 25 August 2018 |
| Time: | 15:45 |
| Type: |  Bell 212 |
| Owner/operator: | Roberts Aircraft Company opb Trans Aero Limited |
| Registration: | N512TA |
| MSN: | 30863 |
| Year of manufacture: | 1977 |
| Total airframe hrs: | 6530 hours |
| Engine model: | Pratt & Whitney PT-6T-3B |
| Fatalities: | Fatalities: 0 / Occupants: 1 |
| Aircraft damage: | Substantial |
| Category: | Accident |
| Location: | Dardanelle, CA -
 United States of America
|
| Phase: | Approach |
| Nature: | Fire fighting |
| Departure airport: | Bald Mountain Helibase, CA |
| Donnell Fire, CA | |
| Investigating agency: | NTSB |
| Confidence Rating: |  Accident investigation report completed and information captured |
On August 25, 2018, about 1600 Pacific daylight time, a Bell 212 helicopter, N512TA, impacted terrain about a one-half mile north of Dardanelle, California. The airline transport pilot received serious injuries. The helicopter sustained substantial damage to the top of the fuselage, the main rotor blades and the tail rotor ninety-degree gearbox. The helicopter was registered to Roberts Aircraft Company and operated by Trans Aero Limited of Cheyenne, Wyoming, as a public aircraft external load flight. Visual meteorological conditions prevailed along the route of flight about the time of the accident and no flight plan had been filed. The local flight originated from a staging area near Bald Mountain, California about 1445.
The pilot was conducting water bucket operations when he heard a one-per-revolution whispering sound emanating from the helicopter. He elected to return to the helibase and accepted the Air Attack controller’s offer to escort him back. While en route to the helibase, at an airspeed about 60 knots, the whispering sound evolved into a vibration that progressively worsened. The pilot then elected to land as soon as possible at a nearby location. Upon arrival to the precautionary landing site, the vibration momentarily stopped and was followed by a loud bang, an aggressive vertical vibration, and a loss of control. The helicopter impacted steep mountainous terrain and rolled once onto its left side. The occupants of the escort helicopter observed the accident helicopter nose over about 20° to 30°, followed by a 360° flat turn before it impacted the terrain.
Examination of the wreckage revealed that multiple components of the main rotor control system had failed along with a span-wise failure of one of the main rotor blades. The drive link associated with the failed rotor blade had failed in overload at its lower lug and swashplate trunnion bearing. The outer race of the trunnion bearing exhibited brinelling consistent with axial movement of the inner section of the bearing. The inner section of the trunnion bearing separated from the rotating swashplate along with the lower lug of the drive link.
Gouges and impact marks found on the arms of the non-rotating swashplate were likely made from the lower lug of the drive link as the inner section of the trunnion bearing began to pull out of the outer race. Contact of the lower lug with one of the arms of the non-rotating swashplate likely resulted in the overload failure of the drive link. These liberated components were not recovered.
The in-flight failure of the swashplate drive link resulted in the loss of control of the associated main rotor blade. The uncontrolled blade, free to move out of track with the other controlled blade, resulted in at least a partial loss of control of the main rotor system. The associated vibrations from the out-of-track rotors likely resulted in the failure of the swashplate support and the total loss of control of the helicopter
Probable Cause: An in-flight failure of the trunnion bearing and subsequent failure of the drive link and swashplate support, which resulted in the loss of helicopter control.
Accident investigation:
 |
|
Sources:
https://www.mymotherlode.com/news/local/397511/donnell-fire-helicopter-makes-a-crash-landing.html
https://www.uniondemocrat.com/localnews/6478754-151/feds-investigate-downed-35-million-helicopter-contracted-to
https://fireaviation.com/2018/08/28/a-few-more-details-available-about-the-helicopter-accident-at-donnell-fire-in-california/
NTSB
https://registry.faa.gov/aircraftinquiry/NNum_Results.aspx?NNumbertxt=512TA%20
http://m.aerialvisuals.ca/AirframeDossier.php?Serial=174313
Location
Images:
Photo: NTSB
Revision history:
| Date/time | Contributor | Updates |
|---|---|---|
| 26-Aug-2018 06:56 | gerard57 | Added |
| 26-Aug-2018 09:16 | Aerossurance | Updated [Time, Operator, Location, Source, Embed code, Narrative] |
| 27-Aug-2018 22:10 | Geno | Updated [Aircraft type, Registration, Cn, Operator, Location, Source, Embed code] |
| 28-Aug-2018 20:11 | Aerossurance | Updated [Aircraft type, Registration, Cn, Operator, Source, Narrative] |
| 30-Aug-2018 19:09 | Geno | Updated [Registration, Cn, Source] |
| 14-Oct-2018 08:12 | Aerossurance | Updated [Source] |
| 14-Oct-2018 08:16 | Aerossurance | Updated [Departure airport, Source] |
| 14-Oct-2018 08:17 | Aerossurance | Updated [Narrative] |
| 14-Oct-2018 08:18 | Aerossurance | Updated [Narrative] |
| 14-Oct-2018 15:35 | Aerossurance | Updated [Source] |
| 28-Sep-2022 08:12 | Aerossurance | Updated [Source] |
| 05-Oct-2022 21:20 | Captain Adam | Updated [Time, Operator, Location, Phase, Departure airport, Destination airport, Source, Embed code, Narrative, Accident report, Photo] |
Corrections or additions? ... Edit this accident description
The Aviation Safety Network is an exclusive service provided by:
Quick Links:
| ASN Home | Send Correction / Feedback |
| FSF Home | Disclaimer | Copyright |
| Contact Us | Privacy Policy |
| Press / Media |
CONNECT WITH US:
©2024 Flight Safety Foundation