The core mission of airlines is to promote safety, and psychological knowledge can assist us in making this process smoother. Here, we summarize some particularly important segments in promoting safety work, understanding how we got here, and the key concepts in promoting safety work. Generally speaking, these are also the things new colleagues entering the airline industry need to know during their initial safety training.
Current Status: Continuous Improvement in Civil Aviation Safety, Yet Not Zero
To understand the safety performance of the aviation industry, the world’s leading aircraft manufacturers Boeing and Airbus release statistics related to aviation safety annually. The graph we refer to is Airbus’ statistics from 2022, covering the period from 1958 to 2021, which shows the proportion of accidents causing complete aircraft damage (Hull Loss) and fatalities. The vertical axis represents the number of such incidents occurring per million flight departures. Overall, we can draw two conclusions:
- Positive Statement: The proportion of accidents causing complete aircraft damage and fatalities continues to decrease. There has been significant progress in flight safety over the past fifty years.
- Negative Statement: No matter how much it improves, it can only approach zero, and significant accidents still occur. This indicates that there is still room for improvement in safety.
We like to see the safety standards of civil aviation continue to improve, but as safety incidents continue to occur, we will never be fully satisfied. The concept of continuous improvement is very important for safety management, and it can even be said to be the only method for safety. Whether these operational environment hazards ultimately lead to major incidents depends on a probability; the fact that nothing happened today does not mean it won’t happen tomorrow. Therefore, only by continuously eliminating hazards and implementing effective risk mitigation measures can we potentially reduce the likelihood of future incidents.
Evolution of Safety Management Perspectives: Technical, Human, Organizational to Systemic Views
So how did the people in the past manage to reduce incidents to their current levels? The reduction of international civil aviation incidents certainly wasn’t achieved overnight. The focus of safety management has gone through various stages, influenced by technological advancement, attribution of incident investigations, and shifts in economic and safety perspectives. According to the ICAO Safety Management Manual, safety perspectives have at least gone through four stages: technical, human factors, organizational factors, and systemic views.
Technical Factors Era
Before the 1970s, the focus of the aviation industry when dealing with safety incidents mostly revolved around technical factors. For instance, issues such as a malfunctioning engine, landing gear failure, or hydraulic oil leak, which could prevent a flight from landing smoothly. Compared to now, early aircraft may have had poor quality or design due to technological limitations, leading to serious incidents. Over time, with technological advancements and improved product designs, the quality of machinery has enhanced.
However, as long as machines are involved, malfunctions may occur. Technically, components failing on an aircraft is nothing new, and the frequency of such issues increases with aircraft age. The real reason why technical factors rarely lead to significant incidents lies in the backup concept and procedure design. Important systems on an aircraft generally have more than two backups, and procedures like the Minimum Equipment List (MEL) specify which components can malfunction without affecting the aircraft’s airworthiness and how long a malfunction can be left unaddressed. These procedures effectively prevent technical factors from culminating in major incidents.
Human Factors Era
Starting in the 1970s, the safety perspective gradually shifted away from purely mechanical factors to the role of human factors. The Tenerife air disaster in March 1977 marked a significant turning point from focusing on mechanical factors to human factors.
Tenerife Air Disaster (1977/3/21)
Tenerife is a small island off the coast of North Africa. Two Boeing 747 aircraft (KLM Flight 4805 and Pan Am Flight 1736) were diverted to Tenerife airport due to a terrorist bomb attack at their original destination, Las Palmas airport. After Las Palmas was cleared and reopened, the control tower instructed KLM to use the runway as a taxiway, taxi to the end of the runway for a 360-degree turn, and wait for takeoff. At the same time, Pan Am followed KLM using the runway as a taxiway, exiting the runway via taxiway C3. Due to poor visibility, prolonged waiting times approaching crew time limits, and other factors, the KLM crew commenced takeoff without permission, colliding with the still-taxiing Pan Am aircraft on the runway. The disaster resulted in the death of 583 passengers and crew members from both planes.
The significance of the Tenerife incident is that two of the most technologically advanced aircraft of the time resulted in such a catastrophic accident, indicating that mechanical factors alone could not explain what happened. Since then, human factors have become central to safety management, with a focus on perception, attention, memory, decision-making, and other aspects of human behavior, which became the safety focus in the 1980s and beyond.
Regarding unsafe human behavior patterns, we will have a more detailed introduction to various types of errors in subsequent sections. Interventions such as Crew Resource Management (CRM) and Non-Technical Skills (NTS) will also be covered in later sections.
Organizational Factors Era
In the 1990s, the focus shifted from cockpit crew or even just crew members, to a broader organizational perspective. At this time, the safety perspective no longer considered safety as solely the responsibility of crew members, recognizing that organizations played a crucial role through supportive activities in the background. Factors such as resources provided by the organization for safety, its own inspection and supervision mechanisms, safety culture, and learning culture formation, were all identified as having a partial influence on the occurrence of incidents.
Given that the organizational aspects are the focus, implementing an organizational management system with various management tools became important. The first edition of ICAO DOC 9589 ‘Safety Management Manual’ (SMM) was published in 2006, outlining the framework for a Safety Management System (SMS), including safety policy, risk management, safety assurance, and safety promotion, and was later upgraded to Annex 19 in 2013. Taiwan’s Civil Aeronautics Administration mandated the implementation of SMS in all airlines in 2009 through the ‘Regulations on Aircraft Flight Operations Management’.
Systemic View
Since the 2010s, founded on the previous three different safety visions and the associated risk mitigation measures, the likelihood of major incidents has continued to decrease. Current discussions revolve around the overall ecosystem of the aviation industry, emphasizing the need for cooperation between legislative bodies, supervisory entities, airlines, and countries, to enhance the overall civil aviation safety performance. Consequently, regions have their safety targets, countries within those regions develop their safety goals and implementation plans according to regional targets, and companies follow suit based on national targets.
Definition of Safety: Reducing Risks to Acceptable Levels
But what exactly is safety? Here, we explain using the ICAO 9859 4th edition definition:
- Safety: The state in which risks associated with aviation activities, directly or indirectly related to aircraft operations, are reduced and controlled to an acceptable level.
- Acceptable Level of Safety Performance (ALoSP): The level of safety performance agreed by State authorities to be achieved for the civil aviation system in a State, expressed in terms of safety performance targets and safety performance indicators. (Note: Since ICAO 9859 4th edition adopts a systemic view, the acceptable level is based on achieving hierarchical targets: regional safety targets, national safety goals based on regional targets, and operators achieving national safety goals. Therefore, the acceptable level is approved by regulatory authorities. Before the 3rd edition, the principle was that the enterprise set the acceptable level, responsible for its own standards.)
The above definitions can be simplified as follows: Safety is about reducing risks to acceptable levels. Regardless of the various execution plans, this acceptable level must be measured and approved by the regulatory authority. In practice, the targets set by airlines should be more stringent than those agreed upon by the regulatory authority.
Actual reduction of risk might sound easy, but it is the most important task within the entire safety operation, and fulfilling the duty of safety requires continuous improvement as its primary method. Safety operations can be highly diversified, including carrying out safety promotion activities, writing safety bulletins, conducting inspections, calculating various types of safety indicators, etc. Many auxiliary tasks support the operation scheme, challenging us to allocate limited manpower and financial resources. However, regardless of other operations, the proportion of work dedicated to “continuously reducing risks” should remain the main focus, receiving sufficient resources to accomplish the task.
Risk Management: Practical Procedures for Reducing Risks
Risk = Severity * Frequency
After identifying potential hazards, risk assessment is necessary. A common risk assessment matrix has its vertical axis representing occurrence likelihood, scored from 1 to 5, and the horizontal axis representing severity, from A (most severe) to E (negligible). This gives a 5×5 matrix. The matrix’s colors indicate different levels of risk: green for low risk, yellow for medium risk, and red for high risk. Different companies may have their risk response rules, one possible example being:
- Low Risk: Considered acceptable risk. An ongoing risk mitigation measure should be in place, and the effectiveness of these measures should be checked continuously. Approval by the operational unit supervisor is sufficient for continuation.
- Medium Risk: Considered unacceptable risk, requiring risk improvement measures to be implemented, reassessing the risk level after implementation to ensure reduction. Submission to and approval by the safety unit supervisor is required.
- High Risk: Operations should stop immediately. Risk improvement measures must be implemented, followed by a reevaluation of the risk level to ensure reduction. Report to and obtain approval from senior management to resume operations.
While a company’s “acceptable safety level” is defined by safety performance indicators and requires regulatory approval, practically, waiting for incidents to happen to report to regulators for acceptability decisions isn’t ideal. Companies can define their “acceptable safety level” operationally through adjustments to their risk matrix: the cut-off between yellow and green. Crossing into yellow or beyond indicates a safety level the company cannot accept, necessitating the implementation of risk mitigation measures.
Risk Management: Elimination and Mitigation
According to ICAO 9589, the listed risk management strategies are Elimination and Mitigation. Occupational safety training personnel might propose more detailed techniques under these two strategies, such as elimination, substitution, engineering controls, administrative controls, and personal protective equipment, but these may not apply to all scenarios. Regarding elimination and mitigation, they are defined as follows:
- Elimination: Refers to the avoidance of risk by removing the risk and avoiding exposure to it.
- Mitigation: Refers to reducing the severity or frequency of the risk.
Practically, due to operational requirements, most identified risks can’t be completely eliminated and require appropriate risk mitigation measures to reduce frequency or severity. For instance, bird strikes are a significant source of hazard in aviation, potentially causing varying levels of engine damage. Bird strike frequency increases from spring and decreases by autumn, with severity depending on the species and size of the bird, larger ones causing more significant damage. Removing birds from the skies is unlikely, but measures to reduce frequency or severity, such as airports increasing grass cutting frequency during breeding seasons to deter egg-laying or enhancing bird monitoring and warning operations, can lower the risk level to an acceptable threshold. Some high-difficulty approach techniques can’t just be avoided; instead, enhanced training or stringent qualification control, allowing only authorized crew to perform such approaches, can manage risks to an acceptable level.
Key Points Summary
- Civil aviation safety has significantly improved over the past fifty years, but incidents still occur, indicating that safety needs continuous improvement.
- Focus on safety has transitioned from initial technical factors, to human and organizational factors, to the current systemic view, reflecting the evolutionary process of focusing on safety. However, all these factors still play an important role in current safety work, requiring suitable risk mitigation measures based on different factors.
- Definition of Safety: Reducing risks to acceptable levels. Therefore, reducing risks and implementing effective risk mitigation measures are the primary core missions of those responsible for safety duties and should receive appropriate manpower and financial resources.
- After identifying hazards, risk assessment should be conducted based on severity and frequency of occurrence. If assessed as medium risk or above, a decision-making process is needed to eliminate the risk or implement mitigation measures, bringing the risk down to an acceptable level.
These contents largely cover foundational safety information and our core work content. We will further discuss how psychological work assists in risk mitigation measures during the process.
