I have seen a number of Access developed
FMEA products on the market, but none that are open source. Having developed a number of Access databases in the past, I would offer the following advice:
1. You're probably better off not attempting to integrate process flow charting directly into the database. A more workable solution is to allow the user to upload a flow chart created in another application and have the Access database store it in a controlled directory and just display a link to the file. (Off topic: My preference is to do the flow charts in Excel, since not everyone has Visio, RFFlow, Smartdraw, etc.).
2. Expect problems if the database grows large. I've created some that started with small user bases that eventually grew to several hundred people. There's a reason that Microsoft recommends using it for only a small number of concurrent users (5-10). A pet project can turn into a babysitting headache. This is the kind of situation that gives Access a bad name. It's perfect for small groups, but beyond that it just doesn't scale well.
3. Learn to design disconnected forms. By that I mean that the data in the forms is not live. I think Access calls them "bound" fields when they are connected directly to the data source. Using bound forms can lead to a lot of concurrency issues (two or more users trying to access the same data at the same time). By default, the forms wizards create bound forms, so it is more of a hassle to create disconnected ones.
4. Run the compact / repair indexes at least once a week and even more frequently if the database grows large.