Accident Eurocopter AS 350B2 Ecureuil ZK-HYO, 16 Aug 2014
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ASN Wikibase Occurrence # 168780
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Time:c. 12:20 LT
Type:Silhouette image of generic AS50 model; specific model in this crash may look slightly different    
Eurocopter AS 350B2 Ecureuil
Owner/operator:The Helicopter Line
Registration: ZK-HYO
MSN: 3885
Fatalities:Fatalities: 1 / Occupants: 7
Other fatalities:0
Aircraft damage: Substantial
Location:Mt Alta, Wanaka, Otago -   New Zealand
Phase: Landing
Nature:Passenger - Non-Scheduled/charter/Air Taxi
Departure airport:
Destination airport:Mount Alta
Investigating agency: TAIC New Zealand
Confidence Rating: Accident investigation report completed and information captured
On Saturday 16 August 2014, the weather was fine and clear with light variable winds in the Mount Aspiring National Park area. The Helicopter Line was using several AS350-B2 (Squirrel) helicopters to ferry heli-ski groups to the top of various ski runs in the area.
One of the helicopters was on its fourth heli-ski flight for the morning, ferrying a group of five skiers and their ski guide to a ridgeline close to the summit of Mount Alta. On the approach to the landing site the helicopter began to descend below the pilot’s intended angle of approach. The pilot discontinued the approach by turning the helicopter away from the ridgeline and down the mountain. However, the pilot was unable to avoid the terrain and the helicopter struck the steep, snow-clad slope heavily and rolled 300 metres down the mountain.
The cabin structure broke apart and five of the seven occupants were ejected from the helicopter as it rolled down the mountain. Two passengers remained strapped to their seats. One of the passengers was trapped under the helicopter and died from his injuries. The remaining six occupants received moderate to serious injuries. The helicopter was destroyed.

TAIC findings (see complete report below):
5. Findings
5.1. The helicopter struck the face of the mountain heavily in a nose-down attitude with a high rate of descent.
5.2. The engine was almost certainly operating normally and delivering a high level of power when the accident occurred.
5.3. The helicopter was loaded by an estimated 30 kilograms above the maximum permitted weight of 2,250 kilograms, with its longitudinal centre of gravity an estimated up to 3.0 centimetres forward of the maximum permissible limit when the accident occurred.
5.4. The helicopter’s weight and the altitude at which it was being flown meant that it was operating at or close to the performance limit for an out-ground-effect hover. It is likely that the initial sink on the landing approach was a result of the helicopter moving into an out-of- ground-effect hover as the airspeed reduced.
5.5. It is unlikely that vortex ring state was a significant factor contributing to the accident. However, it could not be ruled out that the helicopter was affected to some degree by vortex ring state at some stage as the pilot carried out his escape manoeuvre.
5.6. The use of standard loading plans for Squirrel helicopters fitted with dual front seats was inappropriate, in that it was possible for pilots and ground staff to follow the plans and operate the helicopters outside their permissible limits.
5.7. The use of standard loading configurations that use standard passenger weights should not be permitted when aircraft are fully loaded and operating close to permissible limits.
5.8. The operator’s policies and procedures for training its pilots were broadly comparable to those of other New Zealand operators and to those of heli-ski operators in Canada.
5.9. The pilot was trained in accordance with the operator’s training standards and was experienced in heli-ski operations.
5.10. There are indications that a culture exists among some helicopter pilots in New Zealand of operating their aircraft beyond the published and placarded limits. Such a culture adversely affects the safety performance of the helicopter sector.
5.11. It is very likely that several of the passengers’ seatbelts were not securely adjusted. If seatbelts are loosely fitting, occupants are more likely to be ejected from an aircraft and the seatbelts are more prone to inadvertently release during an accident.

The Commission made three recommendations to the Director of Civil Aviation to address the safety issues.

The key lessons arising from this inquiry are:
● flying in mountainous terrain places additional demands on a pilot’s skills and an aircraft’s performance. Both could be at or near the limits of their capabilities. Operators need to ensure that their safety management systems address the additional risks associated with flying in such an environment
● the use of ‘standard’ or ‘assessed’ passenger weights is not a licence to exceed an aircraft’s permissible weight and balance parameters. Any aircraft being operated outside the permissible range will have a higher risk of having an accident, particularly when being operated near the margins of aircraft performance capability
● it is important for operators to keep comprehensive, formal records of all pilot training. Historical training records provide the basis for ongoing performance monitoring and professional development, particularly given natural attrition as safety and training managers move through the industry
● seatbelts are only effective in preventing or minimising injury if they are fastened and properly adjusted. Aircraft operators must ensure that passengers and crew fasten their seatbelts and adjust them to fit tightly across their hips
● vortex ring state is a known hazard for helicopters. To avoid the hazard, pilots must:
a. remain alert to the conditions conducive to the formation of vortex ring state
b. closely monitor the airspeed and rate of descent during the final approach
c. initiate recovery action at the first indication that they may be approaching vortex ring state.

Sources: (inquest)

Dec 2017 TAIC final report :

Accident investigation:
Investigating agency: TAIC New Zealand
Status: Investigation completed
Duration: 3 years and 2 months
Download report: Final report
Other occurrences involving this aircraft

22 Feb 2009 N353P PHI Inc 0 Cave Creek, Maricopa County, Arizona sub
Hard landing.


Revision history:

16-Aug-2014 03:05 angels one five Added
16-Aug-2014 05:24 Geno Updated [Aircraft type, Operator, Total fatalities, Source, Narrative]
16-Aug-2014 10:55 Aerossurance Updated [Nature, Narrative]
17-Aug-2014 20:28 Aerossurance Updated [Aircraft type, Source]
19-Aug-2014 19:21 Aerossurance Updated [Registration, Cn, Phase, Destination airport, Source, Narrative]
25-Aug-2014 17:44 Anon. Updated [Cn]
09-Sep-2014 15:21 Aerossurance Updated [Source]
22-Apr-2016 19:17 Aerossurance Updated [Source]
07-Dec-2017 08:02 Iceman 29 Updated [Source, Embed code, Narrative]
07-Dec-2017 20:22 harro Updated [Operator, Nature, Embed code, Narrative]
07-Dec-2017 22:28 Aerossurance Updated [Time, Aircraft type, Source, Narrative]
30-Jun-2020 12:23 Aerossurance Updated [Source]
02-Feb-2022 05:03 Ron Averes Updated [Location]

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