Checklist navigation involves not only linear movement through a checklist, progressing step by step as each one is accomplished and the next one is reached, but also jumping within a checklist past inapplicable items to others that are and jumping out, and sometimes back in, to and from other checklists, materials, or information. Checklist navigation and the amount of jumping required are
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dependent upon a number of factors. The first is the modality of checklist presentation; closed loop items on integrated ECLS and inhibiting unnecessary secondary or consequential checklists
streamline the process greatly. Depending upon how it is programmed, ECLS can also integrate items and information from multiple checklists in a way that appears seamless to the pilot (Burian & Martin, 2011).
Checklist navigation is also very much influenced by the philosophy with which the QRH, ECLS, checklist, and related materials, have been developed. One-stop shopping, Get-in Stay-in, inclusion of opt-out gates, consideration of a wide range of circumstances that might require additional or alternate actions or information, assumptions about the effectiveness of checklist procedures—each affects how pilots will move through the various materials consulted during emergency/abnormal situation response as well as how many separate things will need to be accessed.
A variety of ways currently used to facilitate this navigation in the checklists analyzed in this study were reviewed earlier. Most items that support this activity, such as single Conditional/Decision Items and Exclusive Conditional/Decision Item Sets, require that some sort of evaluation or choice be made. Obviously, the more branches available and the more jumping required, the greater the mental workload involved in accomplishing the checklist and the greater the opportunities for error. Thus, various formatting and graphical conventions are used to facilitate the identification of not only the Conditional/ Decision Items themselves, but also in identifying the subordinate items that go with the various decision branches and in directing the pilots to those items.
Although items, formatting, and graphics associated with navigation and jumping in the checklists analyzed were identified and described, a table-top analysis of the checklists, such as what was conducted in this study, cannot truly evaluate their effectiveness in supporting checklist navigation. That can best be accomplished through an observation of pilots actually using the materials. Even so, in this study the following observations pertaining to checklist navigation were made:
• It was sometimes difficult to follow flow lines, particularly when they continued across multiple pages, several ran in parallel to each other because of nested Conditional/Decision and subordinate items, and when they connected to both the right and left sides of items (right and left margins).
• Exclusive conditional sets were most easy to evaluate when they were presented or identified as a set in some way, rather than when each item was presented without any indication that its complement(s) (other item(s) in the set) was presented later in the checklist.
• In a few checklists analyzed, the pilot is sent to a second checklist that immediately sends the pilot to a third. It was not clear why the jump to the second checklist is necessary. • Conditional/Decision Items, despite the inclusion of special graphics or formatting, were
sometimes missed when they appeared very near the “checklist continued” item/Checklist Title repetition at the top of a second or later checklist page in the QRH. Spacing between the Conditional/Decision Item and the indentation of the subordinate items contributed to the eye jumping directly to the subordinate items.
• Some Conditional/Decision Items are compound or complex which can be more difficult for pilots to correctly evaluate when under stress.
• All checklists, but particularly an ECLS, should have a way to “undo” an incorrect evaluation of a (open loop) Conditional/Decision Item. In other words, the subordinate
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items for all potential evaluations of a Conditional/Decision Item must be available or easily accessible in case an incorrect evaluation of the item has initially been made. The ECL allows this, as of course do all paper checklists, but it unclear how this is managed on the ECAM.
Jumping within a checklist should not necessarily be considered an undesirable thing; indeed, jumping within a checklist means that checklist designers have tried to anticipate many of the circumstances under which the checklist and alerted actions might be needed to provide a degree of customization and the best support possible to the pilots. What is essential, however, is that during checklist development all the various path ways through the checklist should be validated and that mechanisms used to facilitate jumping are thoroughly vetted and evaluated in a simulator under situations as similar to those experienced during a real event as possible.
Even so, to reduce workload and the potential for error, jumping should be minimized or streamlined whenever possible. For example, during an emergency/ abnormal situation if an action should be performed when the aircraft is in icing conditions and there is no discernable penalty if action is performed when the aircraft is not in icing conditions, the Conditional/Decision Item asking if the aircraft is in icing conditions could be eliminated and the pilot simply directed to complete the action. Research is needed to help identify the most effective ways to facilitate emergency/ abnormal checklist navigation, particularly when they are presented in paper and stand-alone ECLS
modalities.