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How to reference maintenance manuals


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I'm going to provide a bit here to help everyone understand how maintenance manuals work when it comes to how they are laid out, and how to identify which one you are using. Unfortunately, it will differ from manufacturer to manufacturer, so I will focus on Rotax as it is the most difficult to understand at a glance, and touch a little on flight design. Hopefully this will be helpful enough if referencing other manufacturers.


First, don't use browser searches for technical data for Rotax or Flight Design (bad practice in general). You'll end up with old editions. Some distributors, flight schools, etc also slightly modify their documents. The only place I work with people regarding rotax or flight design is when documentation comes from flyrotax.com, and flight design documents from flightdesignusa.com or flightdesign.com, as it's directly from the manufacturers themselves. Our browser searches will likely be different, especially if you consider that your browser settings might be different (are you using bing, yahoo, google?). Even then, the major search engines personalize the results, prioritizing local services, so unless we are your neighbor on the same ISP, it's not going to help.


Anyways, the more info you provide, the better. The most complete and helpful way when talking about manual references, is to be as specific as possible. Some things to provide: aircraft make and model (almost always applicable as manufacturers can customize engines to a degree, so if in doubt, just provide it); engine make and model (if relevant. for OLD engines [older than 2005 roughly] you'll need to provide a year or serial # as they WILL BE DIFFERENT from more recent ones); appliance make and model (if relevant); type of publication (maintenance manual, line manintenance manual, wiring diagram, drawing, service bulletin, etc); some sort of identification of which version of the publication, such as the edition of the publication, revision of the publication, or other identifier like a service bulletin number and revision; chapter; page; and paragraph or figure. Yeah, holy crap that's a lot. But, think about how many aircraft exist, how many engines exist, how many appliances exist, how many publications exist, and then think about how many times they have been revised... you get the idea. If you aren't specific, confusion can result.


IMPORTANT NOTE ON EDITION AND REVISION: You will notice in the lower left corner of Rotax manuals, it will have the edition and revision. You can reference the edition, but do NOT read the revision from here without specifying page numbers!!! In fact, unless you know when to make an exception, just don't read it from there at all! The reason that the revision is printed down there, is for people who print out their manuals. If something is revised, Rotax provides the "Revision Pages" as a download that people can use to swap out only the changed pages in their books, instead of reprinting the entire manual. That's why the revision numbers change back and forth as you flip through the manuals! The best place to read the revision in a Rotax manual, is in the "Table of Amendments" or "Summary of Amendments" section at the beginning of the manual, and read the largest number in the "no." column on the left. That is the current revision number.


For flight design manuals, they have a similar layout in the "revision status" or "list of effective pages" sections.


Sidenote: Why Flight Design and Rotax? Why don't you also revise the cover page for ease of identification? ALMOST EVERYONE ELSE DOES IT THIS WAY!!!


OR A SIMPLER WAY FOR DIGITAL JUNKIES INSTEAD OF EDITIONS AND REVISIONS: Just provide a link to the same exact document that you are referencing (don't find one like it, we need to see the exact same one you are using). It would be preferred to be from the manufacturer's official sources, but in cases like Cessna and Piper, you have to buy their manuals (annoying), so just provide a scan of the pages in question (fair use law does permit this to a degree, but keep it to a few pages).




Rotax manuals follow the ATA-100 codes, which has some similarities to the dewey decimal system. Basically, it's an ordering system that sections things based on the system type and subsystem type. For example, finding information on how to check compression is a "Scheduled Service" item, which is chapter 12-20-00. Yeah, this sorting system is still daunting for the uninitiated, the point is that providing that "12-20-00" will at least put people in the ballpark when referencing compression. Don't worry too much about what it means (that's for us mechanics), just provide that chapter number!


Page number is pretty simple too, just read that off under the chapter number. BUT THERE'S A GOTCHA! Page numbers start over with each chapter! Don't just provide the page number without the chapter, you will only annoy people!


Paragraphs are denoted with a number and right parenthesis. For example, 4.2) is a subparagraph of 4). Numbering starts over with each new chapter, so don't forget that chapter number!


Figures aren't consistent unfortunately. Heavy MM does section-number, while line MM just says a figure number and starts over with each chapter). Just read it off.




Flight design's manuals are more intuitive for the uninitiated, but are sometimes more of a pain in the butt for those of us used to the ATA codes. Plus, I'm sure their documenting department hates themselves for not using ATA 100, which is much, much easier to document with even with computer aid.


Why? Because they use this format: chapter number (which is completely freaking arbitrary) . aircraft section (still somewhat arbitrary, ex landing gear) . aircraft part assembly (ex: brake system) . aircraft part (ex: brake pad replacement) . type of maintenance (ex procedure). This reference would be Imagine, before computers, how big of a pain it would be to renumber a whole manual if you had to add an entirely new section at the beginning... Anyways, that's also a big pain to search for without a page number, so please reference the page number in the upper right (it's formatted as chapter - page, example 5-13, read off both).




Example, if you have a rotax engine question, specifically about carbs, and want to know what part 30 and 34 is in a figure:


2009 Flight Design CTLS (not needed for most carb stuff on rotax, but again, provide if in doubt!)

Rotax 912 ULS engine

Rotax Heavy Maintenance Manual, Edition 1, Revision 4

Chapter 73-00-00

Page 25

Figure 73-13


Notice how much info I provided? Do this, and I can find exactly what you want me to see.


Now for a kicker. I chose this example for a reason... Go to the next page. ITS ANOTHER DIAGRAM ALMOST EXACTLY THE SAME AS THE PREVIOUS PAGE! I referenced the 912 series carbs above, but on the next page is the 914 series carbs. Part 30 and 34 DIFFER SLIGHTLY! This is how mix ups happen and could have far reaching repercussions! BE VERY PRECISE!


If you accidentally told me page 26 instead of page 25, I would have caught the discrepancy because figure 73-13 is for 912 series assembly diagrams, while 73-14 is for 914 series engines. I also know the difference between the two carbs, and would have recognized it right away and asked for clarification. There's a few other inconsistencies that I would notice too, that's why lots of information pointing to the reference is good!


Now, obviously, you don't have to do this all the time, or every time, but I hope I made my point about precision being important!


I hope this helps!

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