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| Date: | Saturday 20 January 2024 |
| Time: | 11:19 UTC |
| Type: |  Eurocopter EC 135T2+ |
| Owner/operator: | Air-Glaciers SA |
| Registration: | HB-ZUI |
| MSN: | 1173 |
| Engine model: | Turbomeca Arrius 2B2 |
| Fatalities: | Fatalities: 0 / Occupants: 3 |
| Other fatalities: | 0 |
| Aircraft damage: | Minor |
| Category: | Serious incident |
| Location: | Rougemont (VD) -
 Switzerland
|
| Phase: | En route |
| Nature: | Ambulance |
| Departure airport: | Saanen Airfield (LSGK) |
| Avoriaz | |
| Investigating agency: | STSB |
| Confidence Rating: |  Accident investigation report completed and information captured |
The HEMS EC 135T2+ force landed following an engine failure.
STSB Conclusions:
The serious incident in which a turboshaft engine unexpectedly shut down during the continuous climb phase was due to fatigue failure of the driving gear in the accessory gearbox. The driving gear failed as a result of a fatigue crack that originated at the root of a tooth, most likely caused during manufacturing or by a one-time overload during engine start-up. However, an overload during start-up seems unlikely, as it would have been noticed by the crew.
The two other engines potentially concerned were identified and examined by the manufacturer. They showed no defects, which makes it possible to consider this an isolated case.
Accident investigation:
 |
|
Sources:
STSB
Revision history:
| Date/time | Contributor | Updates |
|---|---|---|
| 29-Sep-2025 09:04 | ASN | Added |
| 29-Sep-2025 09:05 | ASN | Updated [Total occupants, Location, ] |
| 29-Sep-2025 10:28 | RobertMB | Updated [Aircraft type, Operator, Narrative, ] |
| 29-Sep-2025 10:51 | Captain Adam | Updated [Date, Operator, Narrative, ] |
| 30-Sep-2025 08:46 | Aerossurance | Updated [Aircraft type, Narrative, ] |
Corrections or additions? ... Edit this accident description
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