Fritz Kaiser Posted April 3, 2017 Report Share Posted April 3, 2017 Hello Gentlemen, is this a problem for us O drivers? My IO550 is 22 years old and has +/- 1600h greetings Fritz MSB05-8B.pdf Quote Link to comment Share on other sites More sharing options...
gsengle Posted April 3, 2017 Report Share Posted April 3, 2017 Not sure what a mandatory sb means for part 91 drivers... unless there is an associated AD. Have you checked the ADs? This looks expensive.Sent from my iPhone using Tapatalk Quote Link to comment Share on other sites More sharing options...
carusoam Posted April 3, 2017 Report Share Posted April 3, 2017 (edited) Private Pilot Reading through... not a mechanic. No experience with these documents... What I see... the first parts... (General Information) 1) initially written in 2005. 2) two parts 1)regarding new cam gear design at that time, 2) resulting clearance issue. 3) So, if you have a 1994 engine that was built correctly in 1994 and the cam gear wasn't changed, you will need this mod when you OH the engine incorporating the new cam gear. 4) If you had the engine OH'd the SB should have been followed at that time. 5) What is bringing a revision of this SB seems to be a change of the level of the document. SB(3) to MSB(1) 6) What is the chance of having the cam gear swapped out to the new design without modifying the block casting to match? Reading the Scope section... 7) it recommends changing the cam gear that has the older design. 8) Time frame: 100 hours, OH not to exceed waiting 12 years, whenever cam gear is accessible. Reading the Safety Intent section... 9) eliminate the possibility of gear tooth fracture. Reading the Configuration Description 10) Not an AD yet. But getting closer... 11) setting the steps that need to be done to get the stronger cam gear in place. 12) setting the steps to modify the casting to properly house the stronger cam gear. Follow-up Questions... Are there any known cam gear failures that we can get familiar with? Seek professional guidance on this. I am only a Private Pilot. Not trained in either mechanics or legal documents. Best regards, -a- Edited April 3, 2017 by carusoam Quote Link to comment Share on other sites More sharing options...
gsengle Posted April 3, 2017 Report Share Posted April 3, 2017 It's #8 I don't know how to interpret. 12 years or 100 hours from when? From this becoming mandatory? And is it mandatory or only for commercial operators who have to follow SBs?Sent from my iPhone using Tapatalk Quote Link to comment Share on other sites More sharing options...
carusoam Posted April 3, 2017 Report Share Posted April 3, 2017 (edited) That 100 hours is from when the document was issued a decade ago..? Which, came a decade after many of our engines were built. Being only a service bulletin, it wasn't mandatory for most of us. Logic: 1) old gear not as strong as new gear. 2) new gear requires a new clearance cut in the casting. 3) Document is moving from SB towards AD. Keep an eye on it. 4) it still may not become an AD. Don't rush to spend money. PP reading of the technical document only... Best regards, -a- Edited April 3, 2017 by carusoam Quote Link to comment Share on other sites More sharing options...
Deb Posted April 3, 2017 Report Share Posted April 3, 2017 I just spoke with CMI. They said that engines manufactured after 8/9/2005 would have the newer gear p/n 656818 and were not affected. According to CMI, it's possible that the camshaft gear doesn't have a serial number, so CMI might not know what part number was installed in an engine (I was a bit incredulous at this). They know date of assembly based on the engine serial number. 2 Quote Link to comment Share on other sites More sharing options...
StevenL757 Posted April 3, 2017 Report Share Posted April 3, 2017 You beat me to it...I was on hold for Ken when I read this. I hung up. :-) Quote Link to comment Share on other sites More sharing options...
carusoam Posted April 3, 2017 Report Share Posted April 3, 2017 (edited) Looking closer into Deb's description... 1) There is probably a build sheet for every engine TCM built, with the record of each part that went into the engine. The lot number of the part is usually included in the record to make things fully traceable... 2) It would be a bit of a surprise if each part didn't have a corresponding identifying and a tracking number associated with it. Aka part and lot numbers... 3) Not having a serial number or lot number would be bad. 4) Not having a part number on it is near criminal. See GM and their hidden (part number) cover-up for ignition switches. They used the same part number to describe two significantly different part designs. (Significant, as in people died because the old part caused a failure where the new part didn't) GM records didn't acknowledge a need for a change in design. Because they didn't have a need for changing the part number. Ethics issue for manufacturing engineers. To be a little more clear... 1) The part number is the most important thing. This is the design of the part that is important to know. Need this to know if it has been changed to the new part or not, from the logs or build records. Without having to open the engine to look. It 2) the serial or lot number is also important. But not as important in this case. If it were a bad lot made of the same design, this is where we would be looking... 3) the proper part can be identified visually by its machined clearance cut. Gaining access for visual inspection will take some effort. Sounds like it May be behind the starter. 4) from the photo in the MSB. The photo is clear enough, I can see the numbers on a bearing surface next to the gear? But there isn't a number visible on the gear itself. 5) tracking at this level is becoming more popular recently. It takes a lot of data handling that was not available back in 1994. Today we are getting pretty good at tracking individual tablets, in a medicine bottle, back to their raw materials when they were originally made. 6) tracking has become more important over the years. It is really dissapointing to find out you have received the wrong part for your machine. It is expensive to have a serviceman in the field waiting for another, correct part. Owners immediately know the quality of your manufacturing team when they can't tell you what part they put in the center of your engine. 7) Lycoming has probably been through a similar situation with their cranks years ago. 8) Electronic records are key! 9) I was unable to see an estimated number of man hours to complete this SB. This estimate usually gives the PP an idea of how costly the exercise may be... Deb, thanks for sharing the phone call details with us. best regards, -a- Edited April 3, 2017 by carusoam Quote Link to comment Share on other sites More sharing options...
carusoam Posted April 3, 2017 Report Share Posted April 3, 2017 (edited) Continuing to report on things I found... or was shared with. Borrowing from other people using the same engine... https://www.aopa.org/news-and-media/all-news/2016/december/20/camshaft-gear-failures-generate-airworthiness-concern-sheet It may have been brand B that had one come apart. FAA records indicate Three gears have lost teeth resulting in power loss. Best regards, -a- Edited April 3, 2017 by carusoam Quote Link to comment Share on other sites More sharing options...
gsengle Posted April 3, 2017 Report Share Posted April 3, 2017 They say the only failures are with the gear manufactured from 1999-2002. Which implies to me the scope is pretty limited if limited to engines made with that part number. '96 model here, whew Sent from my iPhone using Tapatalk Quote Link to comment Share on other sites More sharing options...
thinwing Posted April 3, 2017 Report Share Posted April 3, 2017 Regardless upping the original service bulletin to "mandatory " is a big deal for any commercial operators...100 hrs to pull the engine ,mod the case to change out the gear...basically they waited till all the previous earlier than 2005 continentals were at least over 12 years old to basically compel an overhaul Quote Link to comment Share on other sites More sharing options...
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