What happened
On 18 November 2016, a Robinson R44 helicopter, registered VH-HHZ, was operating to support fire-fighting personnel near Sleisbeck, Northern Territory.
At about 1600 Central Standard Time (CST), the pilot conducted an approach to a landing site they had already landed at twice that day. The landing site was a flat rocky surface, but one side had a slight downwards slope. The pilot confirmed the wind direction from smoke nearby and approached the landing site into wind. As the pilot lowered the collective[1] and the helicopter’s skids touched down, the helicopter started to slide to the right. The pilot attempted to correct the sideways movement, but the main rotor blade struck a rock, and the helicopter started vibrating. The pilot rolled off the throttle and applied right pedal, but the helicopter rotated to the left and the horizontal stabiliser struck a rock. The helicopter sustained substantial damage (Figure 1). The pilot and two passengers were not injured.
Figure 1: Accident site showing damage to VH-HHZ
Source: Helicopter operator
Findings
These findings should not be read as apportioning blame or liability to any particular organisation or individual.
- The helicopter landed on a portion of rock, which had a slight downwards slope. The actions taken by the pilot, when the helicopter started to slide, did not prevent the main rotor blades and the horizontal stabiliser from striking a rock.
Safety action
Whether or not the ATSB identifies safety issues in the course of an investigation, relevant organisations may proactively initiate safety action in order to reduce their safety risk. The ATSB has been advised of the following safety action in response to this occurrence.
Helicopter operator
As a result of this occurrence, the helicopter operator has advised the ATSB that they are taking the following safety actions:
The company issued a notice to flight crew emphasising the importance of conducting a thorough aerial assessment before committing to landing at any remote location including confined areas.
The company also reminded pilots that in hot humid conditions, fatigue can occur a lot sooner that during the cooler months. They should make every effort to remain hydrated and inform the chief pilot immediately if they feel adversely affected.
Safety message
Civil Aviation Advisory Publication 92-2(2), Guidelines for the establishment and operation of onshore Helicopter Landing Sites, sets out factors that may be used to assess the suitability of a site for helicopters to land and take off. The guidelines include the recommendation that helicopter operators conduct thorough risk and hazard assessments for a basic helicopter landing site and implement controls to manage identified hazards.
Aviation Short Investigations Bulletin - Issue 57
Purpose of safety investigationsThe objective of a safety investigation is to enhance transport safety. This is done through:
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