posted November 19, 2020

In September 2005, the first International Helicopter Safety Symposium was staged in Montréal Canada, for the purpose of considering additional safety measures which might be adopted by the helicopter industry. All major stakeholders were in attendance, including professional associations from five continents and 13 countries, maintenance organizations, manufacturers, operators, accident investigators, and regulatory agencies.

The event was hosted by the American Helicopter Society (AHS) and the Helicopter Association International (HAI), and as a direct result of the gathering, the International Helicopter Safety Team (IHST) was formed. The mandate to the IHST was to develop a safety program which could be used to continuously advance the safety progress of the helicopter industry in reducing accidents. What eventually came from that symposium and others which followed, were some data-driven helicopter safety tips, recommendations for better helicopter training, and identifying the need for universal usage of safety features like the helicopter safety belt.

Engine failures

The International Helicopter Safety Team reviewed a full 50 years of data which was available, in order to determine the most common causes of helicopter accidents, and this review was intended to provide the foundation for its recommendations on how to improve safety measures. Interestingly, one of the most obvious potential causes of failure was found to be one of the lowest statistically-occurring causes, that of engine failure. After reviewing all available data, it was found that engine failure was the cause of only 6.4% of all helicopter accidents during the five decades of data. This is probably since technology for engine manufacturing was fairly mature, as opposed to other components of helicopters, and the maintenance procedures used.

Non-engine failures

This category of accidents refers to mechanical failures of any kind on helicopters other than those occurring to the engines. Since helicopters were newer in design than commercial airplanes, and many of the parts used in the manufacture of helicopters were much newer than well-developed engines of the time, a larger number of accidents were caused by non-engine components. It was found that 11.6% of helicopter accidents were attributable to non-engine failures. Although this is nearly twice the figure of engine failures, it should be remembered that this is a very broad category which takes in literally every other part used in the manufacture of a helicopter.

Maintenance issues

During the study, it was found that about 8.7% of all helicopter accidents were caused by maintenance issues. This means that either proper maintenance was not performed on a regular basis, or that improper maintenance was performed, and the helicopter was not truly prepared for safe operation. At least some of the maintenance issues were known to be due to the fact that in the early days of helicopter operation, proper maintenance procedures were not clearly identified.

Pilot error

For the purposes of the study, helicopter accidents which were due to pilot error were lumped together with all other unknown causes, and this category was by far the largest at 73.2%. Part of the reason that there were so many unknown causes was the fact that for much of the period studied, there simply were not good on-board recording devices in use. The black box devices famously used by modern aircraft were not available in the earlier days of helicopter operation, so when some accidents occurred the cause could never be determined, and the cause was simply labeled as unknown. However, it is likely that a good many of these unknown causes were in fact due to pilot error. 

Where we’re at today with safety 

One of the recommendations resulting from the massive study conducted by the IHST was that all helicopters should be equipped with cockpit information recorders (CIR’s), so that all relevant data could be collected and analyzed. An annual safety review is now conducted by the IHST, using information supplied by more than 40 regional teams around the globe, all of which recognize the need for constant analysis of accident causes. All of this has resulted in a tremendous reduction in the frequency of helicopter accidents, with the following areas specifically identified as being worthy of greater future attention:

• greater usage of on-board Safety Management Systems
• adoption of wire-strike prevention systems
• when needed, usage of night vision technology
• universal adoption of Flight Data Monitoring
• mandatory usage of helicopter safety belts
• Health & Usage Monitoring system implementations
• recurring helicopter training for pilots and maintenance personnel
• stricter application of manufacturer’s maintenance specifications