Why FIFOs fail in Aerospace

I was teaching a Lean Fundamentals class recently and I was on the topic of FIFO lanes. An employee raised her hand and said “We’ve had a lot of FIFO lanes here in the past but they never work. The signs are still up all over the place but they aren’t real FIFOs. Do you know why this happens?” Wow, I thought, what a great question.
After some reflection, I came up with a few key reasons why FIFO Lanes and systems commonly fail in Aerospace environments. I thought it would be good to write a quick post and share these with you.
1.       Lack of flexibility
2.       Single FIFO used when Multiple FIFO made more sense
3.       Not sized properly
4.       Lack of adherence to the standard work
5.    Physical Space
I’ll explain #1 in a bit more detail then elaborate on the others in a later post. In Aerospace environments, there needs to be some flexibility in flow systems. Expedites do happen, and as lean practitioners, we can’t ignore this fact. Rework also happens and we can’t ignore that either. If no flexibility exists in the FIFO system to accommodate these types of parts, then the system will fail. Let’s pretend I set up a FIFO lane and tell everyone on the shopfloor that it’s always First in, First Out no matter what. Now a customer comes along and tells us that they need work order 1234 right now. When that part arrives at my FIFO lane, it needs to jump the queue to meet the customer’s request. Now what have I done to my credibility and the credibility of the system in the eyes of the people on the shopfloor? Probably just ruined it. In Aerospace environments, some flexibility needs to be built into the system and there needs to be standard work around that flexibility. For instance, lets say I build in an expedite lane next to my standard FIFO lane. The standard work would say that the operator always pulls from the expedite lane first then the standard lane when expedite is empty. In that case you would need someone to “police” the expedite lane to make sure every part does not go there.
That’s it for now – stay tuned for some more info on 2-5…

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