Loss of an engine

[TomM]

Well, every now and again things just come together. I took off the cowling and looked at the back of the engine and found a gaping hole where a mag should be.......see attached. The drive gear was dislodged and stuck between the mag and the accessory case. I pulled the gear out and amazingly enough, found all the other parts to the drive side of the mag in the bottom of the cowling. All the bearings were still in the gear as well, and no marks on it. I am having a hard time figuring out how all that stuff ended outside the engine instead of all ground up.......My lucky day????

Obviously the nuts that lock down the mag just dont fall off in 1 minute - they work themselves loose, so this had been happening over time. My plane had been leaking more oil this year than last year, and I am going to point the finger at one of the mag hold downs coming loose. The other hold down was still in place, and must have been enough to keep it from rotating and messing up the timing. All my pre-flight mag checks are accompanied with a 75 rpm drop, match by both mags.....so no timing issues.

I spent the day taking off the cooling baffles and getting access to the mag. Next trip i will bore scope the accessory case to make sure all the gears look fine, remove the mag, check the parts and order any replacement items.

As a followup to mshac, my plane is older and does not have the access panel. It is on my list of things to do though......