MIT Research on Airline Safety: Trends and Global Disparities

What is Aviation Safety?

Understanding the true meaning of aviation safety is crucial. It’s not just about preventing accidents or measuring safety through incidents per million departures. The definition of safety goes deeper, involving comprehensive risk management and control measures.

The International Civil Aviation Organization (ICAO) defines safety as the state where risks associated with aviation activities are reduced and controlled to an acceptable level. These activities directly relate to aircraft operations and encompass everything from technical issues to human factors.

Measuring Safety in Aviation

Safety in aviation is not solely about preventing accidents. It involves managing risks associated with various factors, including technical incidents, human errors, and health-related issues like the spread of communicable diseases (e.g., COVID-19). Other factors include cabin air intoxication, high-altitude health risks, and conditions like deep vein thrombosis (DVT) and cardiac issues due to fatigue.

Learn more about aviation safety measures.

MIT Research: Improvements in Airline Safety

A significant study by MIT professors, “Airline Safety: Still Getting Better?”, reveals that passenger aviation safety has improved dramatically over the decades. The mortality risk of flying halved every ten years—a trend similar to Moore’s Law. From 1968 to 2017, the global death risk per boarding decreased steadily, maintaining a 7.5% annual reduction in mortality risk.

Despite the progress, the COVID-19 pandemic introduced new risks, particularly concerning virus transmission during flights. The study also highlights that while global safety improved, some high-risk nations still lag behind the safer ones, although they are making gradual progress.

Worldwide death risk per boarding for five decades from 1968 to 2017.

Source: Barnett (2020).

The global death risk per boarding steadily decreased from 1968 to 2017, with a 7.5% annual compounded reduction in mortality risk. This decline continued even as the absolute risk became very low. From 2018 to 2022, the death risk per boarding dropped further to 1 in 13.7 million, a 42% reduction from the previous decade’s risk of 1 in 7.9 million. This significant decrease suggests it is not a random fluctuation, maintaining a 7.0% annual decline, consistent with the long-term trend. 2018-22 is split into pre- and post-Covid-19 phases, with the pandemic causing a sharp drop in global passenger traffic starting in 2020.

Air travel safety varies significantly across the globe. Countries are categorized into three tiers based on their commercial air safety records. In 2018-2022, third-tier countries had 36.5 times more fatalities per passenger boarding than top-tier countries, highlighting regional safety disparities.

Three tiered categorisation

The first tier includes countries like the United States, EU nations, and others like Japan, Australia, and Canada, with a death risk per boarding of about 1 in 80 million. The second tier comprises nations like India, Brazil, and Turkey, sharing similar safety records. The third tier includes all other countries, which, despite improvements, still lag behind the top tiers in safety.

Notably, in the 2018-2022, the first two tiers experienced 153 fatalities, with one major accident in China. Despite improvements, third-tier countries have a higher fatality rate but are showing progress by reducing fatalities by half. Barnett emphasizes the continuous efforts and advancements in air safety, particularly in top-tier countries, even though maintaining the rate of improvement is increasingly challenging.

The COVID-19 pandemic was anything but a near miss (Velu and Iyer, 2021); it was a full blow to our entire society. Aviation, by design, is prone to take huge yet ambiguous roles in the evolution of pandemics, being one of the major casualties but also enabling the effective spread of contagion through a highly efficient, global transportation system. Without changes to how we live and travel, the COVID-19 pandemic will not be the last pandemic to hit our society. Air travel played a significant role in spreading COVID-19 by enabling the movement of potentially infected individuals across different regions. This led to widespread travel restrictions, resulting in substantial financial losses, including an estimated $370 billion in airline revenue and $200 billion in global tourism losses between January 2020 and January 2021. Governments intervened with over $160 billion in aid to support the struggling aviation industry. By the end of 2023, air travel rebounded to 94% of pre-pandemic levels, but high transmission periods of SARS-CoV-2 still occurred, making the prevention of virus spread a public health priority.

The CDC noted that SARS-CoV-2 transmission is more likely in enclosed spaces with minimal distancing, such as aircraft cabins. Studies show that factors like the number of occupants, time spent in enclosed spaces, and ventilation significantly impact airborne transmission of the virus. Despite airlines’ claims that HEPA filters and airflow systems in aircraft are protective, evidence suggests that transmission still occurs on flights.

Global Disparities in Air Safety

Air safety varies significantly worldwide. Countries are categorized into three tiers based on their commercial air safety records. For instance, top-tier countries like the United States, EU nations, Japan, Australia, and Canada have the lowest death risk per boarding. In contrast, third-tier countries, although improving, still face higher fatality rates.

Despite these disparities, a continuous effort has been to enhance aviation safety globally, particularly in high-risk regions.

Health Risks and Long-Haul Flights

Air travel, especially on long-haul flights, can exacerbate various health conditions, including:

• Heart Disease: Patients with coronary artery disease or heart failure should have a health check before flying.
• Deep Vein Thrombosis (DVT): The risk increases on flights longer than 4 hours, so preventative measures are essential.
• Chronic Obstructive Pulmonary Disease (COPD): COPD patients should carry bronchodilators and notify airline staff of their condition.

Factors such as hypoxia (reduced oxygen levels), low humidity, and changes in barometric pressure during flights aggravate these conditions. Understanding these risks is crucial for ensuring passenger safety and well-being.

Check out our in-depth guide on managing health risks during flights

Conclusion: The Dynamic Nature of Aviation Safety

Aviation Safety, in the context of aviation, is a comprehensive concept that goes beyond mere accident prevention. It encompasses a range of measures and conditions that protect passengers, crew, and aircraft from various risks, whether technical, human-induced, or related to health concerns such as communicable diseases and physical conditions exacerbated by flight.

Safety is not just about reducing the number of accidents per million departures; it is about managing and controlling risks to an acceptable level, as defined by the International Civil Aviation Organization (ICAO). This includes addressing technical failures, human errors, and health-related risks that might occur during air travel.

A study from MIT highlights the impressive improvements in aviation safety from 1968 to 2017, with the mortality risk decreasing consistently over the decades. However, the COVID-19 pandemic posed new challenges, particularly in managing the transmission of viruses within the confined spaces of an aircraft cabin.

Health conditions such as heart disease, asthma, epilepsy, and recent surgeries can be aggravated by the conditions experienced during long-haul flights, such as hypoxia, low humidity, and changes in barometric pressure. The safety of passengers with these conditions depends on careful preparation, consultation with healthcare providers, and adherence to medical advice before, during, and after flights.

In conclusion, safety in aviation is a dynamic and multi-faceted concept that requires ongoing vigilance and adaptation to new challenges, including health-related risks, to protect all those involved in air travel.