Aviation safety investigations & reports

In-flight break-up involving a Robinson R44, VH-ZNZ, 41 km NW Mossman, Qld, on 18 November 2016

Investigation number:
AO-2016-156
Status: Completed
Investigation completed
Phase: Final report: Dissemination Read more information on this investigation phase

Final Report

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What happened

On 18 November 2016, at about 1244 Eastern Standard Time, a Robinson R44 II helicopter, registered VH-ZNZ, broke-up in the Mount Windsor National Park, about 41 km north-west of Mossman, Queensland. The helicopter was on a charter flight with one pilot and one passenger on board. Following impact with the ground, the passenger was fatally injured and the pilot was seriously injured. The helicopter was destroyed.

What the ATSB found

The ATSB found that one of the main rotor blades struck and separated a section of the tailcone of the helicopter from the airframe, which resulted in a near vertical descent of the helicopter main body through the forest canopy. The wreckage indicated there was low engine power and rotor speed at the time of the strike, which was likely the result of a main rotor blade stall event. The ATSB was unable to determine what precipitated the blade stall event.

The ATSB also found that the helicopter was likely operating in at least moderate turbulent flight conditions, which were not forecast. The turbulence was associated with a wind strength of 15‑25 kt in undulating terrain at a high density altitude (reduction in ambient air density). The Pilot Operating Handbook did not prohibit flight in either the forecast or actual conditions, but the presence of moderate turbulence potentially placed the helicopter in an environment for which it had not been flight tested.

Safety message

This accident highlighted the importance of impact-activated emergency locator transmitters. The activation of the transmitter on impact was the trigger to start the search and rescue operation, and recover the pilot, who may otherwise have not survived. ATSB research report AR-2012-128 provides guidance to owners and operators on how they can maximise the reliability and effectiveness of emergency locator transmitters.

Although it could not be determined if the wind and associated turbulence contributed to the accident, it is important for pilots to consider the effect of the terrain on the weather forecast, which could result in their helicopter not achieving its predicted performance.

Download final report
[Download  PDF: 2.76MB]
 
 
 

The occurrence

Context

Safety analysis

Findings

Pilot and aircraft details

Sources and submissions

Appendices

Terminology used in this report

General details
Date: 18 November 2016   Investigation status: Completed  
Time: 1244 AEST   Investigation level: Defined - click for an explanation of investigation levels  
Location   (show map): Mount Windsor National Park, 41 km NW Mossman   Investigation phase: Final report: Dissemination  
State: Queensland   Occurrence type: In-flight break-up  
Release date: 05 March 2019   Occurrence category: Accident  
Report status: Final   Highest injury level: Fatal  

Aircraft details

Aircraft details
Aircraft manufacturer Robinson Helicopter Co  
Aircraft model R44 II  
Aircraft registration VH-ZNZ  
Serial number 11954  
Operator Stock-Air Heliworks  
Type of operation Charter  
Sector Helicopter  
Damage to aircraft Destroyed  
Departure point Mossman, Qld  
Destination Mount Windsor National Park, Qld  
Last update 05 March 2019