The Transport Accident Investigation Commission added two new significant items to its Watchlist of most pressing concerns on 27 October 2016.
One involves the popular Robinson helicopter and the other safety issues for pedestrians and vehicles using railway level crossings. The latter is an emerging issue, especially in Auckland.
It has also updated three existing Watchlist items covering recreational boat users; technologies to track and locate aircraft, ships, boats and rail vehicles; and substance abuse in the transport sector.
There are around 300 Robinson helicopters registered in New Zealand comprising around 40% of the total helicopter fleet.
Since 1996, the Commission and the Civil Aviation Authority (CAA) have investigated 14 “mast bumping” accidents involving Robinson helicopters, costing the lives of 18 people.
Mast bump is contact between an inner part of a main rotor blade or a rotor hub and the main rotor drive shaft or “mast”. The outcome is usually catastrophic.
“We understand what mast bumping is, but it is often difficult to determine exactly what happened to cause the mast bump,” said Commissioner and spokesperson Stephen Davies Howard.
“We know the condition results when Low-G occurs – a bit like when you leave your stomach behind when going over a hump on a country road – or from an inappropriate control input. Low-G can be caused by turbulence, but it is not normally a condition that causes concern beyond discomfort,” said Commissioner Davies Howard.
“However, it can lead to mast bumping which too often has fatal consequences in Robinson helicopters with their rotor head design.”
The Commission had also identified that the rate of Robinson helicopter in-flight break-ups accidents in New Zealand had not been significantly reduced by the adoption of US Federal Aviation Administration measures intended to help prevent such accidents.
“We also found that the format of the Robinson flight manuals and terminology did not draw enough attention to safety critical instructions and conditions that could result in serious injury or death.
“Four of our earlier recommendations made as a result of Robinson mast bump accidents have yet to be actioned. We therefore remain concerned that there is a real risk that we will see more of this type of accident.”
The second new Watchlist item concerns the safety for pedestrians and vehicles using level crossings.
The systems designed to reduce the risk at rail crossings were not keeping pace with change. These included change in vehicles, trains and passenger numbers; changes in rail infrastructure; pedestrian behaviours; and also ambiguities in who was responsible for the interface between road and rail.
“For instance, in early 2015 the Commission opened an inquiry into a pedestrian killed at the Morningside station in Auckland. The design of the pedestrian ‘maze’ at the time was constructed to force pedestrians to face in the direction of the approaching train before they turned to cross the tracks.
“However, with increasing rail traffic, signalling changes were made to allow trains to run in both directions with the result that trains could approach from behind pedestrians so defeating the maze design.”
The Commission had also investigated several accidents where road-legal vehicles had become stuck on rail level crossings or had been too long to clear a rail level crossing and then stop, as required, at an adjacent road intersection.
“We found there is no routine procedure for measuring the profile or vertical alignment of the road at rail level crossings, which means there could be other level crossings in New Zealand on which low-slung but road-legal vehicles could become stuck,” said Commissioner Davies Howard.
The Commission has also updated its Watchlist concerning the need for recreational boat skippers to demonstrate their knowledge before taking to the water; further changes needed in the area of substance abuse; and also the need for transport regulators to do more to encourage and where reasonable, require air, rail and marine vehicle operators to use available tracking and location technologies.
The Commission’s prime role is to determine the circumstances and causes of accidents and incidents to help ensure that such accidents will not be repeated in the future.It can only make recommendations. It is up to the regulators, operators, the Government and the people involved in transport every day to embrace them or not.
The Watchlist highlights the Commission’s most pressing concerns. The list may contain transport-related items that represent high social, economic or environmental risk. It may highlight systemic issues affecting transport safety, or it may be an issue that policy makers, regulators or operators have been slow to act upon.