As most everyone is aware by now, Continental Motors released an updated Mandatory Service Bulletin, MSB05-8B (click to view the original bulletin), requiring camshaft gear replacement effecting a large portion of the fleet. I don’t want to beat a dead horse, but I would like to clarify a couple points for everyone as the opinions and assumptions have run rabid online.
First and foremost, you should not immediately be concerned. Camshaft gear failure is not common, nor have I honestly seen one in my thirty plus years in the industry. This includes the hundreds of PCE engine overhauls coupled with the associated work I have done for the NTSB during accident investigations. It is NOT a pending industry safety hazard. I would coin it more as a Continental Motors’ lawyer induced attempt to minimize presumed liability. That’s a mouth full… Though some in the industry see it as more profit related than liability, I hope this is not the case. Some online forums are even asking if it is just a coincidence that the bulletin was released the same day Continental Motors announced their grand $60M plant expansion. Like I said, opinions are running in all directions.
The final draft of the airworthiness directive (if one is truly issued on the subject) will ultimately tone down the urgency of compliance. Recent talks between industry representatives and the FAA have resulted in the possibility of some sort of repetitive inspection requirement and/or replacement at next overhaul or engine disassembly with the slightly thicker (0.60” thicker) camshaft gear. In my opinion, any repetitive inspection requirement will be a waste of time and money as little can be gleaned from a visual inspection of the gear.
How it all shakes out in the end, we will have to wait and see. We should all be seeing another revision to the bulletin soon. Until it is all written in stone (meaning an airworthiness directive), I wouldn’t be concerned in the slightest. Fly on and enjoy life!