Watch Out for FOD March 12 2019

Starting my mechanical engineering career in the aviation field taught me some good habits. One thing that is obsessed over in aviation is FOD, which stands for both foreign object debris and foreign object damage. Foreign object debris causes foreign object damage. FOD is a big deal in aviation, because even something as little as a lost washer can migrate around inside the aircraft and possibly touch some wires and short them out. Maybe a lost screwdriver can jam up a control cable. Maybe a lost nut will bounce around in the cockpit during negative-G maneuvers. 

We had strict rules and procedures for preventing FOD from being left on the aircraft. Many of these principles are also good practices in the garage.

1. Make sure all your tools are accounted for at the end of the day. A tool box with cutouts for every tool makes it quick to spot if a tool is missing. You don't want to leave any tools in your car.

2. Before sealing off an area of an aircraft, multiple people inspect for FOD before the area is sealed up. The same should be done with cars. For example, thoroughly check the head before covering it back up with the valve cover. Thoroughly check the engine bay for tools before closing the hood. I've known people to close their hood on some tools and leave dents in their hood. Check the intake manifold and the intake ports before bolting the intake manifold back on.

3. Have a system for storing fasteners that you remove. This will not only prevent you from losing fasteners, but also keep you more organized. At the aerospace company I worked at, we used small drawstring bags to hold fasteners, but if you don't have any, Ziplock bags also work.

4. Block off areas that can ingest FOD as soon as possible. For example, after you remove an intake manifold, use rags or tape to cover the intake ports so that fasteners, insects, trash or dust can't get inside and cause damage.

5. Clean periodically as you work. This keeps the workspace cleaner and more organized, which gives FOD fewer places to hide.

Recently, I was replacing a valve cover gasket, and the gasket was old and brittle. I took the time to account for all the pieces of the gasket and noticed that a small piece was missing.

Underside of valve cover with missing pieces of gasket.

It turned out that there was a piece of gasket that had broken off and was left in the valvetrain. This piece of gasket could have caused serious damage if it migrated to the wrong part of the valvetrain. This simple check saved me from possibly having to replace the head.

Missing piece of gasket found in the head.

I hope that you will now be more mindful of FOD and that this knowledge can possibly save you from incurring damage to your car from FOD.