The New Zealand Transport Accident Investigation Commission (TAIC) has added Robinson helicopters to its Watchlist of most pressing concerns. There are around 300 Robinson helicopters registered in New Zealand comprising around 40 percent 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,” said Howard. “Low-G can be caused by turbulence, but it is not normally a condition that causes concern beyond discomfort.
“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 U.S. 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.”
Louisa Patterson, CEO of Over The Top Helicopters, has issued the following statement in response to the TAIC adding Robinson helicopters to its Watchlist of most pressing concerns:
“This is a moment of importance for worldwide aviation. I applaud the Transport Accident Investigation Commission for its warning and courage.
“TAIC is so concerned about Robinson helicopters in New Zealand that it has taken the unprecedented step of exposing the Robinson on its Watchlist. This Safety Commission has recognized the characteristics of the Robinson main rotor system — that it is prone to mast bumping and in-flight break-ups.
“I have suffered the ultimate loss and I don’t want others to suffer. Anyone who reads the many reports and does basic research will appreciate the safety risk worldwide.
“It is now over to the regulators and the politicians to promptly take action with courage before greater loss results — to families and the economy. Any aircraft that is prone to unknown, in-flight break-ups, killing people, should not be allowed to operate in New Zealand conditions, particularly for commercial activities like tourism, where the public have a trust in safety systems and certifications.
“The Aviation Safety Network database shows that globally in the last 21 months there have been 78 Robinson accidents in the R44 model resulting in 44 fatalities. Of these, 31 occurrences are unexplained in-flight break-ups, resulting in 64 percent of the deaths.
“This demonstrates that Robinson helicopters have a disproportional accident and kill rate around the world, not just in New Zealand. Our Transport Accident Investigation Commission is to be commended for showing leadership and I hope other countries heed the warnings and take action also.”
Full details of the Watchlist can be found online.
It would be nice to actually see the numbers based on flight hours and flight type compared to other two bladed helicopters in the region. This story looks bad, but it leaves anyone with a working brain wondering. Is there really a problem or is it that there are so many more of these cheaper Robinson helicopters, flying so many more hours and more hazardously than other two bladed similar helicopters? This article just scares people without good research to back it up. You have to know and respect the limits of the aircraft you fly. Are the majority of these flights sight seeing or risky people with little skill helicopter hunting in the unforgiving mountain environment with an overloaded helicopter?