Well, TCM seems to want an AD to get off the hook legally and tries to play it via the FAA. Some say they should be sued for bad design, some say no, that’s gonna cost us all eventually. Fact is, should this become an AD, a lot of money flows towards TCM and a lot of owners will face, what, 5-10k at least to get it repaired, if TCM doesn’t offer a compensation of some sort. Since it’s not usually visible in the logs which gear is installed, a bit of uncertainty remains, which could have an effect on the value of those planes that haven’t been positively identified as safe. There will be a public hearing in the process towards a possible AD. Should it become an AD, it’s not really sure how it will have to be enforced. Could be within 100hrs, or could be at next overhaul.
Dear Euroflyer. Many apologies if you found my remarks were out of place. I am no expert but I received the Mike Bush email and this is part of what he said……………..
Best I can tell, such failures are extraordinarily rare events. Savvy manages the maintenance of many hundreds of 520- and 550-powered aircraft with the older-style gear installed, and in the eight-plus years we’ve been doing so we have yet to encounter a single camshaft gear failure. In the wake of the Bonanza incident, Continental’s legal department may want to get all the older-style gears out of the system ASAP for liability reasons. (A more cynical school of thought holds that issuance of an AD requiring immediate teardowns would create a big financial windfall for the company. Personally, I’m more inclined to blame the lawyers than the bean counters.)Italic
I was not making light of the failure & I can see my post could be taken as being flippant. Savvy believe the risk is very small and I was really trying to look at this from the perspective of if one had the huge expense of an engine teardown, would there be other ways to minimise the risk of flying for the same amount of money would yield far bigger benefits in safety.
Having said that, if I had that issue I would be very worried as I often fly over water.
Apologies taken :) Nevertheless, this is a bad thing. If it hits, it hits bad. No metal, no oil analysis, no leaning, nothing prevents that. It’s always full failure, immediately. Like Fukushima. It might be rare, but if it happens, it’s fully catastrophic.
Just got this in email
This came on email just now:
Today Mike Bush has posted the following on his facebook page:
Fantastic news for owners of Continental 520/550 engines: The FAA has determined that no Airworthiness Directive against our camshaft gears is warranted at this time. Continental’s MSB05-8B has been revised and demoted as CSB05-8C to reflect this. Only 13 camshaft gear failures could be documented among a population of 26,000 engines, and we’re aware of only one that resulted in an in-flight engine failure and forced landing. The proposed camshaft gear inspections would have been enormously expensive. Continental Motors and the FAA worked very constructively with aircraft owner groups, and ultimately reason and common sense has prevailed. Kudos to everyone who participated in achieving this great outcome.
Pfeeew! Close call!
The other side of these MSBs, and this one is similar IF it doesn’t become an AD) is that you don’t really know if it is going to break when you are flying.
I see this Conti MSB was not based on a large number of engine failures, so one can IMHO take a chance on it. Now let’s say this Lyco MSB is based on a similar % of engine failures. The Lyco discussion belongs to the other thread linked above, and no doubt will materialse there as and when the FAA does or doesn’t make it an AD, but if it was my engine I would be seriously concerned about flying with it.
You get these considerations in the homebuilt world where ADs can be disregarded (in most registries) but I think most of the owners simply chose to take the risk.
