ASN Wikibase Occurrence # 222755
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Date: | Friday 8 March 2019 |
Time: | 08:05 LT |
Type: | Bell UH-1B Iroquois |
Owner/operator: | Iron Eagle Helicopter Inc |
Registration: | N64RA |
MSN: | 65-12854 |
Year of manufacture: | 1965 |
Total airframe hrs: | 15834 hours |
Engine model: | Honeywell T-53-L13 |
Fatalities: | Fatalities: 1 / Occupants: 1 |
Aircraft damage: | Destroyed |
Category: | Accident |
Location: | Olympic Peninsula, WA -
United States of America
|
Phase: | Manoeuvring (airshow, firefighting, ag.ops.) |
Nature: | Cargo |
Departure airport: | Forks, WA |
Destination airport: | Forks, WA |
Investigating agency: | NTSB |
Confidence Rating: | Accident investigation report completed and information captured |
Narrative:The pilot departed on his first external load flight of the day; shortly thereafter, employees heard a mayday call over the company radio. The helicopter was found inverted in the designated logging area, with the cargo line attached to the cargo hook and the grapple attached to a log. Examination of the airframe and cargo hook revealed no anomalies or mechanical failures that would have precluded normal operation.
Examination of the engine revealed that the gas generator first stage sealing disk had fractured and separated into three major pieces. Multiple internal components of the engine were subsequently damaged as a result, including all four turbine rotors and nozzles. An examination of the first stage sealing disk revealed fracture features consistent with low cycle fatigue.
The overhauled engine was installed into the accident helicopter about 8 months before the accident. The sealing disk was installed into the engine at the time of overhaul and had previously accrued 1,067.3 hours and 2,134.6 cycles.
The operator had not kept an accurate documentation of engine cycles, and it was unknown who was responsible for documenting the engine cycles into the daily flight logs. A review of maintenance records and the helicopter's electronic cycle counter revealed that the sealing disk had exceeded the published life limit of 6,900 cycles. The last documented cycle value was 9,023.13. The cycle counter had recorded 12,023.19 cycles.
Following the sealing disk separation, and subsequent internal damage, the engine lost all power, necessitating a forced landing via autorotation. Due to the low altitude and densely tree covered terrain, it is unlikely that the pilot had reaction time to release the load which became entangled in the trees as he was attempting autorotation.
Probable Cause: A total loss of engine power due to the failure of the gas generator sealing disk as a result of the operator's exceedance of the sealing disk life limits at too low an altitude for the pilot to accomplish a successful autorotation which resulted in the collision with terrain.
Accident investigation:
|
| |
Investigating agency: | NTSB |
Report number: | WPR19FA091 |
Status: | Investigation completed |
Duration: | 2 years 1 month |
Download report: | Final report |
|
Sources:
NTSB WPR19FA091
FAA register:
https://registry.faa.gov/aircraftinquiry/NNum_Results.aspx?NNumbertxt=64RA Location
Media:
Revision history:
Date/time | Contributor | Updates |
09-Mar-2019 08:30 |
gerard57 |
Added |
09-Mar-2019 08:42 |
gerard57 |
Updated [Aircraft type] |
09-Mar-2019 10:11 |
Captain Adam |
Updated [Source, Narrative] |
09-Mar-2019 10:37 |
Aerossurance |
Updated [Time, Location, Source, Embed code, Narrative] |
09-Mar-2019 12:01 |
RobertMB |
Updated [Aircraft type, Registration, Cn, Operator, Source, Embed code, Narrative] |
09-Mar-2019 13:43 |
Captain Adam |
Updated [Narrative] |
09-Mar-2019 14:00 |
Aerossurance |
Updated [Aircraft type, Narrative] |
09-Mar-2019 20:43 |
A.J.Scholten |
Updated [Source] |
09-Mar-2019 21:02 |
Anon. |
Updated [Source] |
02-Feb-2021 10:50 |
Aerossurance |
Updated [Source, Embed code, Narrative] |
26-Jun-2021 11:14 |
Aerossurance |
Updated [Source, Embed code] |
08-Jul-2022 18:31 |
ASN Update Bot |
Updated [Time, Cn, Other fatalities, Nature, Departure airport, Destination airport, Source, Embed code, Narrative, Category, Accident report] |
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