ASN Wikibase Occurrence # 211448
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| Date: | Friday 25 May 2018 |
| Time: | 09:47 LT |
| Type: |  Bell UH-1H |
| Owner/operator: | Northwest Helicopters I Inc |
| Registration: | N111DR |
| MSN: | 64-13699 |
| Year of manufacture: | 1996 |
| Total airframe hrs: | 21244 hours |
| Engine model: | Lycoming T53-L-13 |
| Fatalities: | Fatalities: 0 / Occupants: 2 |
| Aircraft damage: | Substantial |
| Category: | Accident |
| Location: | Olympia Regional Airport, WA -
 United States of America
|
| Phase: | Take off |
| Nature: | Test |
| Departure airport: | Olympia, WA (0WN4) |
| Olympia, WA (0WN4) | |
| Investigating agency: | NTSB |
| Confidence Rating: |  Accident investigation report completed and information captured |
The purpose of the maintenance test flight was for a track and balance of the tail rotor and main rotor blades. The pilot reported that during his preflight check and walkaround, everything looked fine with no anomalies noted. After becoming airborne and performing a hover check, the pilot proceeded to transition to forward flight, when he experienced a loss of tail rotor thrust. This led to a near-vertical rotating descent and hard landing, which resulted in substantial damage to the tailboom and lower fuselage.
On on-site examination found that both pitch change link bolts and the tail rotor pitch change horn were only finger tight and found no evidence of cotter pin installation. One of the two crosshead bolts found in the debris field showed thread wear damage but was observed to be relatively complete.
The accident could have been prevented if, during the rigging process of the tail rotor assembly, the crosshead bolts and the tail rotor pitch change bolts had been properly torqued and cotter pins had been installed. Additionally, had company quality control personnel identified the improper installation of the tail rotor assembly before certifying the helicopter for flight, or had the pilot detected the missing cotter pins during his preflight inspection, the anomalies could have been corrected.
Probable Cause: A loss of tail rotor thrust due to the improper installation of the tail rotor assembly by maintenance personnel resulted in the pilot's inability to maintain control of the helicopter as he began transition into forward flight from a hover, which resulted in a hard landing. Contributing to the accident was the failure of company quality control personnel to identify the improper installation of the tail rotor assembly before certifying the helicopter for flight, and the pilot's inadequate preflight inspection.
Accident investigation:
 |
|
Sources:
NTSB WPR18LA147
FAA register: http://registry.faa.gov/aircraftinquiry/NNum_Results.aspx?NNumbertxt=111DR
History of this aircraft
Other occurrences involving this aircraft
| 24 July 1998 | N83NW | Northwest Helicopters, Inc. | 0 | Libby, MT | |
sub |
Location
Media:
Two injured in Bell UH-1H helicopter crash at Olympia airport, WA, USA. The helicopter from NW Helicopters had just taken off on a test flight when it experienced a mechanical issue.https://t.co/WP6WcMFOBr pic.twitter.com/eOwbRHxU5P
— Planes Of Legend (@PlanesOfLegend) 26 mai 2018
Revision history:
| Date/time | Contributor | Updates |
|---|---|---|
| 25-May-2018 18:39 | Aerossurance | Added |
| 25-May-2018 18:40 | Aerossurance | Updated [Phase] |
| 25-May-2018 18:40 | Aerossurance | Updated [Narrative] |
| 25-May-2018 18:42 | Aerossurance | Updated [Operator, Total occupants, Source, Narrative] |
| 25-May-2018 18:47 | Aerossurance | Updated [Aircraft type, Registration, Source, Damage, Narrative] |
| 25-May-2018 18:52 | Aerossurance | Updated [Aircraft type, Registration, Cn, Source] |
| 25-May-2018 18:53 | Aerossurance | Updated [Narrative] |
| 26-May-2018 04:52 | Iceman 29 | Updated [Cn, Embed code] |
| 26-May-2018 15:53 | Aerossurance | Updated [Source, Embed code] |
| 09-Jul-2022 06:36 | ASN Update Bot | Updated [Time, Operator, Other fatalities, Departure airport, Destination airport, Source, Narrative, Category, Accident report] |
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