News: Blogs

9 October 2018


Blogs: HeliOffshore’s System Reliability & Resilience Workstream is Driving a Cultural Change in How We See the Safety and Resilience of the Human-Machine System

by Scott Carmichael

If there is a single concept that drives and inspires the work of HeliOffshore’s Safety Reliability & Resilience (SR&R) Workstream it is the firm conviction that we need to treat the machine and the human being as one safety system. By taking this holistic approach to enhancing the safety of offshore helicopter operations that we will get, in the first instance, short- to medium-term improvements and then, in the longer term, a profound cultural change in how we think about and manage the safety and resilience of the human-machine system.

In temporal terms, there are two aspects to this approach: looking at accidents and events that have happened in the past and how we can avoid these happening again; and, also, trying to identify and stop the safety threats and risks that we don’t yet know about. We have to focus on the things that keep happening, while at the same time being increasingly conscious of the things that haven’t happened yet. 

It’s an approach inspired by the work of statistician Abraham Wald, who was employed by Britain’s Royal Air Force during World War Two to devise plans for better protecting aircraft from enemy bullets. It wasn’t practical to armour-plate entire aircraft and the air force’s conventional thinking had been to examine aircraft returning from raids for bullet holes and then add armour to aircraft in these places. However, Wald turned this thinking on its head by pointing out that the aircraft that had NOT made it back from their missions had likely been downed by bullets hitting other parts of the airframe—on the basis that the returning aircraft had survived whatever bullets had impacted them. In Wald’s view, the air force needed to add armour to the places on the returning aircraft that had NOT been hit by bullets.

 This preventative approach has inspired our four core SR&R projects: 

  • • Joint Reliability Study
  • • Return to Base Rates
  • • Maintenance Errors
  • • Human Hazard Analysis

The first three of these projects are based on thorough analysis of what has already happened. The fourth—Human Hazard Analysis—is essentially looking for what hasn’t yet happened and trying to deduce what could make it happen and how that can be stopped. It also provides a way to test the results from the first three projects.

When a manufacturer designs an aircraft they carry out a system safety assessment to identify criticality on the basis of the potential severity of the failure of components and systems in terms of how catastrophic this would be. In response to this assessment, aircraft designers create maintenance tasks in order to ensure that these components and systems stay safe. Essentially, a maintenance task exists to provide a continuing level of safety and so there has to be 100% confidence each task can be completed without themselves being subject to an error or safety issue. This is critical because, ultimately, a maintenance task is barrier between normal operations and a disaster. The realisation that the maintenance engineers themselves can make mistakes has prompted us to develop and implement barriers to support them in their work as a last line of defence.

There are two dimensions to HeliOffshore’s Human Hazard Analysis project.

Firstly, we’re looking at helicopters currently in service and conducting analysis of maintenance tasks associated with these that should generate some short- to medium-term safety improvements. These actions might include, for example, the introduction of better tools, improved procedures, more focused training and the redesign and modification of some components and systems.

To achieve this, HeliOffshore has launched a series of Human Hazard Analysis workshops that allow engineers from operators and aircraft manufacturers to collaborate closely. In our first workshop involving HeliOne and Airbus we were able to identify 99 items for potential improvement and Airbus is now prioritising these with a view to make improvements to the design and/or maintenance process. The proposed changes included changes to documentation, additional tooling for engineers and possible modifications to the aircraft. Airbus have expanded their maintenance human factors approach, to include the human hazard philosophy at the core. They have started generating their own internal initiatives to explore new techniques, including virtual reality simulations of maintenance tasks to find improved, human friendly design and processes. 

Secondly, in a more forward-looking approach, our hope is that manufacturers will use the knowledge gained from Human Hazard Analysis to improve the design of next generation aircraft so that they are less susceptible to errors that can occur in maintenance, and less vulnerable to their impact. Similarly, operators and their maintenance organizations can learn their own lessons, prompting them to take actions such as arranging more focused training and qualifications, as well asking for improved support from manufacturers. In May, Leonardo Helicopters enlisted HeliOffshore experts Dr Hazel Courtney and Dr Simon Gill to conduct a Human Hazard Analysis process to support the design of a new service bulletin.

HeliOffshore’s Joint Reliability Study looks squarely at the performance of the machine (i.e. the aircraft and its key systems, including engines). Not every aspect of reliability has a direct impact on safety, but by taking a total system approach we can better identify the areas where poor reliability may negatively impact on the industry’s safety performance. This will allow the operators and manufacturers to consider an additional element when priortising reliability improvement projects.

By gathering reliability data from across the global offshore helicopter fleet, we have a far better opportunity to identify the things that are most commonly going wrong, as well as looking at what maintenance tasks are associated with these and—by extension—what level of safety risk is introduced by having to do these repeatedly and potentially introducing further errors to the system. This collaborative approach is helping us to point manufacturers to the reliability issues that most need to be resolved to strengthen safety performance, and it is more efficient for them if the operators are collectively requesting that the same items be prioritized.

We’re also taking more of a ‘big picture’ look at Maintenance Errors that get recorded by operators under their Safety Management Systems. Again, by looking at these across the global fleet, we get a singular view of maintenance error trends that guide us to where the remedial action is needed and can have the greatest positive impact on overall safety performance. 

In the first instance, our approach to collecting maintenance error data is to assess the outcomes of the errors such as cowlings left unsecured or maintenance over-flys (in which aircraft exceed limits between maintenance).

At this point, we are not trying to collect data with a view to identifying underlying cognitive causes, slips, lapses or omissions, but rather to simply understand the effect the of maintenance error. Our thinking is that this approach will allow us to quickly identify and separate errors that are common and related to specific helicopter designs and those that are related to maintenance operations. We will be looking for trends in these errors. 

In a second phase, we will establish teams of volunteers from HeliOffshore member companies represented on the Technical Steering Group that oversees our System Reliability & Resilience workstream to do more in depth studies. Their goal will be to understand the underlying causal factors for the errors and so determine the actions we can take collectively to reduce repeat occurrences.

From observing the collected data we will also try to accelerate implementation of successful techniques and practices used in the industry to identify errors. This will also increase the amount of information we can share within the industry.

For manufacturers and regulators this approach yields a far more complete picture of error trends and causes than they would otherwise get from mandatory occurrence reports alone. By sharing data in this way we stand to get a complete breakdown of the types of errors commonly associated with individual aircraft types. We should also get better at detecting errors as the process makes it clearer what to look for and how.

One of the first sets of data to be harvested from the new HeliOffshore Safety Intelligence Programme is Return to Base data from aircraft currently accounting for just over 60 percent of our members’ combined offshore fleet. This is a very specific and significant set of reliability data highlighting technical defects that resulted in flight crew having to change their flight plan and return to base prematurely. 

While the decision to return to base is perfectly sound from a safety point of view, we want to be able to reduce the exposure of crews to increased workload that could increase the risk of errors being made. Any deviation from a flight plan has the potential to introduce a new set of safety challenges to an operation. These events also can erode the confidence of passengers in the safety of offshore helicopter transportation.

By conducting a detailed analysis of RTB data from across the fleet, we can better understand what factors are causing these incidents. Through working with the aircraft manufacturers, we should be able to remedy the most common causes of RTB events and, in the process, improve overall reliability and yielding a welcome in the cost efficiency of operations.

Together, these four System Reliability & Resilience projects address different parts of HeliOffshore’s Safety Performance Model and they will definitely yield some specific short-term improvements. In the longer term, the projects are taking the industry on a journey of continuing improvement. Ultimately, we want to achieve a process as part of our HeliOffshore Safety Intelligence Programme through which we can systematically collect data for maintenance errors, joint reliability and return to base events. Then we will be well placed to identify all these occurrences that pose the biggest threat to safety and to deploy the most effective actions in the frontline to mitigate these risks. 

Scott Carmichael is HeliOffshore’s Systems Reliability & Resilience Project Manager.