How is safety ensured in the aviation industry?

Of course, to someone who is curious about aviation, questions about safety may arise when it comes to flying. Many passengers travel by plane each year as according to ICAO, ‘the total number of passengers carried on scheduled services rose to 4.5 billion in 2019’. With this huge number, many passengers are worried about the safety of their flights, often asking questions such as how does a plane fly? How safe is flying? Is my safety ever at risk? And these questions are all important, as safety should always be prioritised both in the air and on the ground. But how exactly is safety ensured in aviation? Well, there are many legal procedures to help manage safety on the ground and in flight. One area of safety management in aviation that I’d like to share with you is Threat and Error Management, which is also abbreviated as TEM.

TEM is a safety management approach to manage all hazards which are likely to be encountered on the ground and in the air. According to the CAA ‘Threat and Error Management is the practice of planning and thinking ahead to predict/identify any potential errors and threats and manage or mitigate those that do occur.’ So, before any errors and threats occur in the airspace or on the ground, pilots will have the opportunity to navigate these possible events and strategize solutions to avoid them. This is great for efficiency as preplanning helps with being prepared if these possible threats and errors were to happen in real time.

To understand TEM, it is important to understand the differences between threats and errors. I’ve included possible definitions for threats and errors as written by the CAA below.

What is a THREAT?

Threats are events or things that occur outside your control and require your attention if safety is to be maintained. Threats are beyond the influence of you as the pilot and they increase the complexity of the flight.

Examples of Threats that may lead to airspace infringements include:

• Distraction caused by task or passengers

• Airspace including NOTAM’d activity

• Weather inc. thermal activity

• Fatigue / Stress

• In-flight malfunctions

• Lack of recent experience (skill fade) or Complacency

What is an ERROR?

Errors are actions or inactions that lead to unwanted or unsafe deviation from the plan. Errors leading to deviation from the plan have the potential to reduce safety margins which could then lead to unforeseen issues and an airspace infringement.

Examples of Errors that may lead to airspace infringements include:

• Navigation errors leading to vertical, or lateral deviations

• Misinterpretation of chart

• Incorrect altimeter setting

• Missed calls / incorrect phraseology

• Misinterpretation of instructions or clearances

• Unsynchronised Direction Indicator

A threat is any condition which has the possibility to increase the complexity of the operation. If not managed properly, these threats can lead to errors. There are different types of threats, external threats, and internal threats. External including those outside of our control such as the weather, system errors and inadequate lighting. Internal threats are those within our control such as fatigue, stress, or disregard for following procedures.

When threats are mismanaged, they can lead to five different types of errors. This being

• Intentional non-compliance errors eg. Completing a pre-flight checklist from memory

• Procedural errors eg. Following procedures but with wrong execution (dialling in the wrong altitude into the plane's instruments)

• Communication errors eg. miscommunication with ATC

• Proficiency errors eg. an error due to a lack of knowledge

• Operational decision errors

Examples of management techniques include full and comprehensive planning for flights. Pre and post-adequate briefing, training, managing distractions and applying all available tools to prevent airspace infringements. In situations where errors have taken place during a flight, aviation authorities carry out investigations with reports and share these with the public so that evidence is shown, and knowledge is shared. This is beneficial to prevent the same errors from happening again. For example, In the UK, aircraft accidents and serious incidents are investigated by the AIR Accidents Investigation Branch (AAIB) under the Department of Transport (DfT), which you can explore further here: https://www.gov.uk/government/organisations/air-accidents-investigation-branch.

Example of an error: Air Transat Flight 236

August 24, 2001: TS 236, an Airbus A330, departed from Toronto, Canada bound for Lisbon, Portugal with 293 passengers and 13 crew members.

During this flight, the plane ran out of fuel over the Atlantic Ocean which led the plane to be glided to an emergency landing in the Azores. Thankfully there were no fatalities. However, there were 18 injuries most of them minor and none life-threatening. Damage was made to the plane as 8 of 12 tyres were blown out.

The reason for the plane running out of fuel was due to there being a fuel leak in the hydraulics system. This was due to an incorrect part being installed. Over time, chafing from vibration in the hydraulic line degraded the fuel line and caused the leak.

In this example, the error was that an incorrect part was installed. There were faults in this as it was later found out and reported that the part was installed due to the engine being replaced. However, the logbook entry detailing the installation of the incorrect part of the fuel line from the replaced engine was not recorded. So, the error was not able to be recognised as a potential threat.

If it had been documented, there may have been a chance for engineers to check the engine replacement and see if everything was operating properly. Threat management would have allowed engineers to recognise the threat and later come up with a strategy to deal with the threat so that it wouldn’t have contributed to the error of the fuel leak.

In conclusion, threat and error management helps to prevent the possibility of errors occurring on flights. TEM provides the most proactive option to maintain margins of safety in flight operations. Knowing TEM as one of the procedures to ensure flight safety, should help reassure those who are worried about flight safety. However, there are still opportunities for errors to take place where threats are not known or acknowledged. The positive thing we can take from this is that aviation authorities across the globe do their best to investigate, report and share their findings after an error has taken place. And by doing this, we can increase the prevention of the same error occurring again.

I hope this has been beneficial for you to understand the importance of Threat and Error Management and how it encourages the safety of flights within the aviation industry. A disclaimer, I am not a professional or fully educated so please do extra research where necessary.