Flow and Check or Do and Verify?
In the July AeroSafety World cover story on checklists and monitoring, the authors make the point that the use of “flow and check” procedures may increase the chance of pilots committing errors of omission.
They specifically state that, in at least one instance and presumably more, “both pilots tasked with the flow procedure did not do it or attended to only some of the flow items. As a result, most items were performed only while using the checklist, eliminating the protective redundancy designed into the flow and check procedure … .” They also argue that requiring pilots to “check things twice” in a short period of time (as I assume they feel is required in the flow and check procedure) is not a good way to ensure the item is actually accomplished.
Finally, they recommend that airlines eliminate excessive repetition of items on any flow and check procedure used.
The main disagreement I have with their thoughts on flow and check procedures is that they do not represent an attempt to get pilots to check the same thing twice at all. Having used flow and check from my very beginnings in military aviation to my current work as an MD-11 pilot, I have never been tasked to do a second check of the same item when, after completing the flow part of the checklist from memory, I have then referred to the actual checklist to confirm that I have accomplished all the applicable items.
Instead of an attempt to get pilots to “check things twice,” I feel that flow and check is more “do and verify,” and is very effective. True, there are times when I’ve forgotten one of the flow items. But that is discovered when I refer to the checklist and read through the items — verifying that my memory did not fail in recalling them all.
I would not like to revert to a situation where I was required to do a normal procedure, or an abnormal procedure that required immediate action to prevent the situation’s becoming worse, while I accessed a checklist (cabin pressure loss comes to mind), solely by taking out the checklist, reading the first item, taking that action, reading the second item, taking that action, etc.
Alan Gurevich, Seattle