There are three basic types of checklists that can help you to keep control of what's going on in the cockpit: flow patterns, mental checklists, and written checklists. But using only one of these checklists isn't enough. To be certain that you prevent errors, you should apply two techniques for every critical event. Many people do this without even realizing it, starting with a flow pattern or mental checklist and backing it up with the appropriate written checklist. Skipping either part of this process leads to mistakes-a fact that I have observed on too many occasions in my 40-plus years of flying and instructing. Flow patterns and mental checklists, the precursors to written checklists, should be stressed in all training programs. A flow pattern is simply a sequence of events or checks that is always conducted in the same way and in the same order. If you do something the same way often enough, once you get into the flow of the activity, the next step becomes almost automatic.
The most common flow pattern is the preflight inspection. Students are taught to start at a certain point and then to return to that point after circling the airplane and checking every nook and cranny. Along the way, they use the written preflight checklist to back up their actions and ensure that they haven't missed anything.
The next flow pattern occurs prior to engine start. It's a good idea to arrange your pre-startup checklist in some kind of order so that your eyes move around the cockpit and instrument panel in the same pattern every time. I start between the front seats and move forward along the floor and then up to the instrument panel, checking each item as I go. I then move horizontally back and forth across the panel as I examine and set the remaining items. Then, before I start the engine, I review the written before-start checklist to be sure I haven't missed anything.
This same idea works for nearly every important series of tasks. To prepare for takeoff, I use a flow pattern during taxi and in the runup area. When I'm finished working my way through the runup flow pattern, I use the CIGARS mental checklist to double check my work: controls, instruments, gas, attitude trim, runup and radios, and seatbelts. Before takeoff, I review the written before-takeoff checklist to be certain I've performed all of the necessary tasks.
Again, the same process works for landing. I run through my flow pattern then go through the GUMPS mental checklist (gas, undercarriage, mixture, prop, and seatbelts), and finally review the written before-landing checklist.
By using the mental checklists and flow patterns first, I can think of the written checklist as a "done list," not a "to-do list." Not everyone agrees with me on this point. Some pilots say that written checklists should be used in a check-and-respond manner. That works well for a two-pilot crew or a student pilot who can identify each item aloud as he checks it. But I think that for other single-pilot operations, the check-and-respond method leaves plenty of room for mistakes. I've seen pilots skip written checklist items after they were interrupted by radio communications, passenger distractions, equipment malfunctions, or traffic conflicts. It takes a little more time to execute the combination of flow patterns, mental checklists, and written checklists, but the results are virtually bulletproof.
The habitual use of flow patterns pays high dividends when emergencies or irregularities occur. It's easy to see when something is out of place as you run through your regular flow pattern. Mental checklists have the advantage of being stored in your head for instant access. You may not have time to find and run through a written checklist (although your written checklists should always be within easy reach and you should know exactly where to find the information you need).
None of us are infallible when it comes to making errors. The best insurance is to check and then check again.
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