CHECKLISTS

Research on human reliability has revealed that when performing a simple repetitive task, it is usual to encounter a human error once every 100 task repetitions. This is considered the baseline human error rate, which can increase if the task performance is affected by stress, fatigue, or insufficient morale. On the other hand, the baseline human error rate can be reduced by practicing the task repeatedly, and the error occurrence can decrease to as little as once in every 1 000 task repetitions.

In order for a checklist to provide valuable assistance for crew members, certain design criteria should be observed:

1. The most critical items on the task-checklist should be listed as close as possible to the beginning of the task-checklist, in order to increase the likelihood of completing the item before interruptions may occur.
2. The more items a checklist has, the more likely one of them is forgotten. A long checklist should be subdivided to smaller task-checklists or chunks that can be associated with systems and functions within the cockpit. Division of pages should be obtained with protruding thumb locators.
3. Sequencing of checklist items should follow the “geographical” organization of the items in the cockpit, and be performed in a logical flow (panel scan sequence). We note that this guideline could conflict with Nos. 1 above. In most cases where this occurs, this guideline (No. 3) should take precedence.
4. The most critical items should be emphasized by use of colour, bold, italics or upper case.
5. Checklists should be designed in such a way that their execution will not be tightly coupled with other tasks - to ensure maximum attention is devoted to the checklist execution.
6. Checklists should be unambiguous and easy to read, presented in easily understood language.
7. Checklists are often within large books, containing different sections (normal, abnormal emergency procedures, etc.), which then have many checklists within each section. These sections should be effectively indexed for fast referencing and cross-referencing other checklists. Colour coordination of sections should be used to provide fast awareness of location and quick movement through the book.