The dirty dozen

The Dirty Dozen

As an individual working in the aviation industry, regardless of occupation (ATC, pilot, manager, engineer) we must be aware that we not only are part of a process chain, but also one of the fail-safes in the accident prevention system. Although a self – check before a task is important (eg. IMSAFE), a constant awareness of the factors which cause us to fail is also crucial to accident prevention.

Below are 12 factors which may cause an individual to become a “hole in the cheese”

1. Lack of Knowledge

Performing a action without the adequate knowledge of the task
Eg. Fixing a component without having proper training

2. Lack of Assertiveness

Knowing that a person is performing a hazardous action and not taking the appropriate steps to prevent it.
Eg. Seeing and knowing the captain continue approach in extremely bad weather and not preventing it.

3. Lack of Resources

Performing a task without the proper tools
Eg. Employees were not equipped with a torque wrench; hence, all bolts were hand tightened.

4. Lack of Awareness

Video embedded from YouTube on 16 August 2012

The absence of situational awareness, or the inability to know what is going on around the individual.
Eg. The pilot commenced take-off, not realising that he had turned onto a runway under construction (SQ006, Taipei)

5. Lack of Communication

Video embedded from YouTube on 16 August 2012

The absence or failure of the effective transfer of messages from one party to another.
Eg. The squelch distorted communications between the KLM 747, PanAm 747 and the ATC. The result was the assumption of takeoff clearance, when in-fact it was a take off NON-clearance.

6. Lack of Teamwork

Video embedded from YouTube on 16 August 2012

Not to be confused with lack of communication. Communication may exist, however if the individuals within a team do not synergise, an environment for failure may develop.
Eg. An employee receiving word that a particular task is urgently required to be performed, however, timely execution is intentionally delayed.

7. Complacency

“Taking it for granted”
Eg. Assuming that the aircraft’s oil level is sufficient and skipping the check

8. Fatigue

Video embedded from YouTube on 16 August 2012

The reduced state of physical and mental function, caused by sleep depravation, high workload, low stimulation or physical and mental discomfort, resulting in the impairment of the execution of a task.
Eg. Long flights on auto pilot results in fatigue toward the end of the flight (ie. Landing)

9. Pressure

Many aviation organisations are pressed for time, increasing the occurrences and magnitude of risk taking to meet organisational goals.
Eg. Backlogged flight schools tend to overwork trainee pilots, forcing them to fly even when they try to exercise their discretion to say no.

10. Stress

Video embedded from YouTube on 16 August 2012

The overload of cognitive function due to internal or external factors which results in cognitive load shedding.
Eg. An engineer at work, who has to deal with a demanding boss, a divorce and an ailing father.

11. Norms

Unwritten rules formed within the workplace, determining acceptable and unacceptable actions.
Eg. It is okay to chip off rust spots from the engine using a screwdriver. Using the de-ruster costs money. Everyone does it, why not?

12. Distraction

External factors which draw the attention away from a dedicated task especially one that is dynamic.
Eg. An ATC controller answering a call from his cell phone while talking down multiple aircraft.


** CASA.** Communication. Retrieved from Youtube on 16 August 2012.

CASA. Fatigue Retrieved from Youtube on 16 August 2012.

CASA Situational Awareness Retrieved from YouTube on 16 August 2012.

CASA. Stress Retrieved from Youtube on 16 August 2012.

CASA Teamwork. Retrieved from Youtube on 16 August 2012.

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