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Date: | Sunday 11 July 2021 |
Time: | 20:04 |
Type: | Bell 412HP |
Owner/operator: | Rotorsun opf Gobierno de Aragón |
Registration: | EC-MTS |
MSN: | 36050 |
Year of manufacture: | 1992 |
Total airframe hrs: | 12463 hours |
Engine model: | Pratt Whitney PT6T-3DF |
Fatalities: | Fatalities: 0 / Occupants: 2 |
Other fatalities: | 0 |
Aircraft damage: | Substantial |
Category: | Accident |
Location: | Ejea de los Caballeros -
Spain
|
Phase: | Manoeuvring (airshow, firefighting, ag.ops.) |
Nature: | Fire fighting |
Departure airport: | Ejea de los Caballeros |
Destination airport: | |
Investigating agency: | CIAIAC |
Confidence Rating: | Accident investigation report completed and information captured |
Narrative:The Bell 412 helicopter, registration EC-MTS, which was at its usual base at Ejea de los Caballeros (Zaragoza), was mobilised to assist in extinguishing a fire that had broken out at a landfill site near the same town.
The helicopter took off from the base with a total of 12 people on board, 10 brigade members and 2 pilots. It left the brigade in the northern area of the fire and proceeded to the Estanca el Gancho reservoir, to the south of the municipality of Ejea de los Caballeros, to load water.
The crew proceeded to carry out the water loading and release test, during which there were warnings of over-torque and low main rotor revolutions. After releasing the water, the warnings disappeared and the crew managed to lift the helicopter a few metres above the reservoir. Immediately afterwards, the low main rotor speed warning reappeared and the helicopter began to descend, finally impacting the water.
The helicopter floated for a few seconds, but then flipped over on its left side. The two pilots exited the aircraft under their own power without damage or injury.
Causes/contributing factors
The cause of the accident was an in-flight loss of control of the helicopter following the disconnection of the main driveshaft from the combining gearbox due to a loss of integrity in the six threaded joints that held them together. This, in turn, occurred because at least one of them had been operating without a self-locking nut, and the remainder were in a deteriorated state due to loss of tightening torque.
The following main driveshaft maintenance instructions and practices are considered possible contributing factors to the accident:
• The reuse of threaded joint elements.
• The lack of a tare torque check, as a requirement for the reuse of the nuts, in the maintenance procedure.
• The operator's tare torque verification practices.
Accident investigation:
|
| |
Investigating agency: | CIAIAC |
Report number: | A-031/2021 |
Status: | Investigation completed |
Duration: | 2 years and 6 months |
Download report: | Final report |
|
Sources:
https://www.elperiodicodearagon.com/aragon/2021/07/11/helicoptero-cae-agua-cinco-villas-54916097.html https://twitter.com/aaffaragon/status/1412518916858040327/photo/2 https://www.mitma.es/organos-colegiados/ciaiac/investigacion/2021/a-031-2021
History of this aircraft
ex D-HAJO, C-GIHK, VT-HGG, B-66188, VH-CFT
Location
Media:
Revision history:
Date/time | Contributor | Updates |
12-Jul-2021 05:43 |
harro |
Added |
12-Jul-2021 05:45 |
harro |
Updated [Location, Narrative, Category] |
12-Jul-2021 05:46 |
harro |
Updated [Date, Embed code] |
12-Jul-2021 05:51 |
harro |
Updated [Time, Aircraft type, Registration, Cn, Operator, Total occupants, Source, Embed code, Narrative] |
12-Jul-2021 07:43 |
Aerossurance |
Updated [Embed code, Narrative] |
12-Jul-2021 14:49 |
Aerossurance |
Updated [Operator, Embed code] |
13-Jul-2021 06:35 |
harro |
Updated [Narrative] |
23-Jul-2021 17:21 |
harro |
Updated [Time, Departure airport, Source, Damage, Narrative] |
23-Jul-2021 17:21 |
harro |
Updated |
03-Feb-2024 07:49 |
harro |
Updated [Other fatalities, Embed code, Narrative, Category, Accident report] |
03-Feb-2024 07:49 |
harro |
Updated [Other fatalities] |
03-Feb-2024 07:54 |
harro |
Updated [Other fatalities] |
03-Feb-2024 07:55 |
harro |
Updated [Other fatalities] |
03-Feb-2024 08:00 |
harro |
Updated [Other fatalities] |
03-Feb-2024 08:02 |
harro |
Updated [Other fatalities] |
03-Feb-2024 08:03 |
harro |
Updated [Other fatalities] |
03-Feb-2024 08:05 |
harro |
Updated [Other fatalities] |
03-Feb-2024 08:10 |
harro |
Updated [Other fatalities] |
03-Feb-2024 08:39 |
harro |
Updated [Other fatalities] |