Rotax 912 Fuel Pump Service Bulletin SB-912-063 June 24 2013
Rotax announces new Service Bulletin SB-912-063 This Service Bulletin recommends the replacement of 912 series fuel pumps with a part number of 892546 and 892 542. Fuel pumps which have pre-installed fuel lines and fire sleeve will need to have the fuel lines transferred from the original fuel pump to the replacement pump.
Rotax-Owner.com has released a new VIDEO to help clarify this requirement. The video explains in detail the steps required to comply.
For UL (Uncertified) engines, CLICK HERE to view the UL Service Bulletin.
For Certified engines, CLICK HERE to view the Service Bulletin.
For more information on this bulletin, view Rotax-Owner's video .
Comments
Great - and I will have to replace mine.
So I ring up the supplier - none in Australia. Will be a month away - so I have ordered. There will probably be a world wide shortage now.
As vague as what I'm about to write sounds, I'm sure you'll understand that none of what I'm about to say is official Rotax advice AT ALL, just what I've been lead to understand. The original fuel pumps (I'll call them "pump A") from about 7 years ago were great !! If you have one some mechanics that work on Rotax (I'm not going to say "Rotax Mechanics") recommend sticking with that pump until it fails. It's failure mode is not to stop pumping, but rather to begin leaking fuel from the weep hole-- when that happens, replace it, otherwise don't (again this is what I've heard).
Then there was an intermediate batch of pumps (pump "B") that looked very similar, but were not made well and quickly failed. Some were still on the shelves a couple years ago-- if you called the shops and asked the right questions they knew what you were talking about and would let you buy the pumps that came out after that (pump C), which were again reliable with a failure mode of weepage, but relatively long life.
Then about 1-2 years ago, a completely new pump style came out (pump D). Shortly after it's introduction, the hoses that were attached to it were found to degrade very rapidly in ethanol (some within 10 hours) and gunked up the carbs badly. The pumps themselves though are not the greatest- different failure mode.
End of story, pumps A & C were good and some recommend you keep them until they fail (again this is not official). Pumps B & D not so great.
Rotax recommends replacing all pumps every 5 years. The way the pumps vary in quality depending on the maker, it's a bit of Russian roulette.
Maybe it's better that I'm vague about the above so that you can investigate and decide for yourself, however consider this:
Mike Busch, aviation maintenance guru "... it never makes sense to maintain a component on a fixed timetable (i.e., every so many hours or so many months) when it's feasible to monitor the condition of the component (which takes two minutes for trim-tab actuators) and maintain it only when the condition monitoring tests indicate that maintenance is actually required. We call this "condition-directed maintenance" (CDM) as opposed to "time-directed maintenance" (TDM)." Quoted from THIS article. However, he has written extensively on this subject, and it is not a new subject. I will find the source, but a WWII British Commander responsible for bomber fleet maintenance noticed that immediately after bombers were brought in for scheduled (timed replacement) maintenance, their failure (loss) rates actually went UP. There's many reasons: mechanic mistakes being one, but also that new parts are essentially being "tested" when first installed: so, if you install 10 new parts, say 1 fails within the first 3 hours. 10% failure rate for new parts. Of those Nine remaining 10 hour old parts, their failure rate for the next hundreds of hours will be much lower than the new failure rate. Yet, when we replace them on a timed basis, we actually increase the failure rate. If instead there are ways of inspecting the part "condition directed maintenance" then doing so is the more effective and safe way of directing maintenance-- thus the military and airlines (who have an extremely low per mile/hour failure rate) follow CDM rather than TDM.
To quote Mike Busch further in that article, "Any owner who follows the manufacturer's scheduled maintenance recommendations is simply throwing money down the drain. Why? Simply because the very notion of a one-size-fits-all maintenance schedule makes no sense from a scientific or engineering point of view. It makes absolutely no sense to apply the same maintenance schedule to an aircraft based in Tampa and one based in Tucson. Or one that flies 30 hours a year and another that flies 300. Or one that's tied down outdoors and another that lives in a heated hangar. Yet that's what the service-manual recommendations call for."
I'll find some more of his articles and post them. They are very interesting. SLSA has no choice but to replace on timed schedules-- bummer if that makes it not only more expensive, but less safe!
What would you do if your ELSA trike manual recommends replacing the motor mounts at say 300 hours but you can easily see, feel and test the motor mounts for condition. Replacing them at 300 hours requires the entire engine to be pulled: all electrical fuel, water, oil and etc connections to be undone then reconnected- potentially introducing damage, errors and air into the systems. Your mounts are at 400 hours and look great. You feel that if one were to fail, the result would be gradual, controlled and not sudden loss of engine / power / control?
What would you do if your ELSA manual recommended replacing the hang bolt ("Jesus Bolt") every 250 hours. Replacement is easy, not error prone and cheap? A failure of the hang bolt would result in "real time" testing the backup hang cable, of which failure is not a good thing.
I think replacing the hang bolt is a no brainer. Knowing how to manage the other issues is not an easy question to answer.
In order not to gunk up this SB notice with off subject discussion of maintenance schemes, let's move the discussion over to a page I'll make on the article quoted above "Secrets of Cost-Effective Maintenance" and keep this page for the specific pump SB alone (ie what it is, how to comply, etc)
Thanks Guys... i will take this on board and follow my judgement. I think the best for me is CDM but before 1st May 2014, so I will keep my pump on order so that I have one when I need it.
As far as I know I have pump A - Pierburg. People swear by them. Given the apparent inability of rotax to supply a robust pump since then, I'm hanging on to mine.
The one comforting thing is that Service Bulletins aren't mandatory for most aircraft. Smart to take under advisement mind you, but not mandatory.