Line Maintenance Course

[Doug G.]

Someone asked me to say something about the Rotax Line Maintenance course I took recently at Leading Edge Airfoils in Lyons, WI. I believe there were two weeks of classes going on starting with the basic maintenance and ending, I believe, with the heavy maintenance (overhaul) course.

 

There were about eight participants at the line maintenance weekend with a variety of reasons for taking the class. Two of us were working only on our own planes, a couple of others were A&Ps finding that there were Rotax engines around needing attention, and others were established LSRM-As who owned their own businesses or looking to start a business. Some had taken the basic maintenance course the week before and were continuing through this one.

 

The center of the course was the tear down of a 912 on the bench. (The engine was one that overheated because of a radiator leak that was not repaired. The owner thought it had enough water and also thought the CHT gauge was not working correctly. It showed water in the overflow bottle, but it was actually overflowing this bottle in flight and the owner never checked tank on top. --So, that became lesson #1.)

 

We disassembled everything down to the crankcase leaving the case, crankshaft and camshaft untouched since spitting the crankcase is the job of an overhaul trained specialist. The process involved removing and inspecting the carbs, gearbox, the water pump, the charging system (coils and triggers) and the electronic modules, the starter and sprag clutch, the fuel and oil pumps, the heads, rocker arms, push rods and lifters, and the pistons.

 

Then we put it all back together again. All this was done in the manner prescribed in the Heavy Maintenance Manual. This is, in a sense, the secret book since it is not available on-line and you cannot purchase it - you have to take the class.

 

There were some tricks learned (ex. the rings have to be positioned in a specific manner before the piston is inserted) and there are a number of special tools which can be quite expensive (some of them can be made). There are things that the assumption would be that you could use an automotive tool but in many cases you cannot, at least without the possibility of damage to the engine.

 

Although I hope I do not have to use any of the information I gained, if I do have a problem I will have a much better sense of what is going on and where, and how, to look. There are basically three things Rotax does not want you to do after this class: 1) split the crankcase, 2) repair the gearbox, and 3) overhaul the carburetors.

 

It was worth the cost. My only frustration was that I planned to fly, but the winds at home were gusting to 31kts and it felt like more - I didn't want to have issues just getting to the runway - so I drove nine hours each way. (That's the one real negative about owning a plane, driving is not as fun as it once was!)

[FastEddieB]

Good info - sounds worthwhile.

 

 

 

Then we put it all back together again. All this was done in the manner prescribed in the Heavy Maintenance Manual. This is, in a sense, the secret book since it is not available on-line and you cannot purchase it - you have to take the class.

 

 

Seems to be up online:

 

http://www.rotax-aircraft-engines.com/portaldata/5/dokus/d05014.pdf

 

[Jim Meade]

Sounds consistent with my experience. Everyone got a chance at "hands on" although sometimes you had to be a little pushy as some students would hog the engine and not let others in unless you spoke up. I think we had more in our class so hands on time for Doug was probably not an issue.

 

We checked that the crankshaft was still assembled at the right angles while we had the engine stripped, and I bet Doug did, too. This is the check you make if it goes overspeed or there is a prop strike.

 

As Doug described, I found everything we did was exactly according to the manual and that there were some tricks or tips in how things went together easier but no "secrets". I remember the tools discussion and how to make some otherwise very expensive tools or when there was a work around.

 

I, too, found it to be a good course and worth the money for me.

 

 

 

 

[Doug G.]

Hmmm... My apologies, I am guessing that the instructor was referring to the overhaul manual that is not available. I probably mistook what he said.

 

One other negative was that things that were talked about while we were working were difficult to take notes on. Once in a while when something was very specific I took the time to jot it down.

With the smaller class I was able to do everything I thought was helpful, mainly the things that were different from my experiences with other engines. With eight if us and four cylinders getting hands on was not difficult. A few things were done more than once so we could each do them.

 

I agree there are no secrets, but there are things that are not explained sufficiently in the manual that it helped to do, and see done since my limited engine experience (I have torn down and overhauled an auto engine.) would have had me doing things incorrectly in some cases.

 

I am also questioning the limitation on carburetor overhaul on an engine that is out of warranty since we toe down these carbs in the Rainbow LSRM class. The rule is, " You can't do it unless you've done it." and we tore them down and reassembled them in class. (It will come down to price vs. time for me when the need arises.)

[Doug G.]

Glad we could make your day Roger. That secret Rotax handshake is something else though.

[Doug G.]

I don't know if owners need to go through this if you are happy with letting someone else do the work, don't have the time, or, you are not mechanically inclined.

 

Mechanics who are going to do this type of work do need this.

 

(Iwill not be taking the overhaul course since I will never have the prerequisites and I do not plan to do any overhauling.)

[sandpiper]

p.s.

Jim,

There really is a secret society and now you and Doug belong to it. Congratulations!

 

I went to class Roger, but I never got the secret "Encoder Ring"!!

[Doug G.]

 

 

I went to class Roger, but I never got the secret "Encoder Ring"!!

It comes in the mail... eventually.

[Jim Meade]

Hopefully, all will gain some perspective from the discussion. There was in my class none of the operating secrets that Roger talks about all the time. Maybe Doug would comment on whether there were operating discussions that suggested practices outside the manual were preferred. It's always interesting to observe Roger change his mind and agree with someone else, then claim that he was right all along.

[sandpiper]

Didn't the manual, at one time, suggest filling the exhaust springs? I seem to remember Eric tucker telling the class I was in not to do that.

[Jim Meade]

Roger,

 

You never shared with us the answers to all the questions you were going to get out of the Bahamas course.

 

No, I think the deal is that while the Rotax manual may be better in some places than in others, that there is no information needed up through the courses that I took that one needed to go outside the manual on.

 

In particular, I am talking about operating practices and procedures that you claim comes from your high level courses and which is not available unless one sits at the knee of Eric Tucker.

 

I simply don't believe it. I think what it does do is let you claim you are an expert and others can't contradict you. What we have on one hand is my reference to documents and your reference to inside information.

[Jim Meade]

Be happy, Roger.

[Doug G.]

Had to dig to find this thread. I got my credentials today for the line maintenance course I took last September. It only took ten months! Better late than never I guess.

[paul m]

If I didn't congratulate you then I'm congratulating you now Doug.

[Doug G.]

Thanks, Paul.