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Greetings all,
I've got a Rotax 912UL here, and the owner wants to do what's required to increase the TBO from 1500 to 2000 hours.

Engine serial number is 4408210. Crankcase part number 888368. Crank Case Serial Number 06.2134

According to SB-912-057UL, paragraph 3.4.1, "Replacement of a crankcase part no. 888364 (to S/N 27.811) through part no. 888368 or part no. 892654 (from S/N 06.0010) is required for TBO extension.

Following Engines are affected:
-912 UL From S/N 4,404718 to S/N 4.407859"

:angry: :angry: :angry:

This document is lousy with typos and bad grammar. This is a document describing the maintenance of an airplane engine; ambiguity here can cause errors in maintenance, errors in maintenance can kill pilots. As a repairman and pilot, I can tell you I don't want to kill or be killed because Rotax can't pony up the dough to have their $#&@ documents proofread by a native English speaker. The sentence describing whether or not I've got to REPLACE A CRANKCASE is completely incomprehensible. Maybe these documents SHOULD be issued by the FAA, then at least we'll get it from someone who can write in our own blankety-blanking language.

:angry: :angry: :angry:

The engine serial number isn't among those effected, but the crankcase part/serial numbers...might be? I can't make sense of it.
  • Re: TBO Extension clarification, please!

    by » 12 years ago


    You have to PAY MORE to get that kind of secret information. Like their manuals, written by an 8 year old Austrian boy, very vague. Also like this site, to see the videos, you have to PAY MORE as if you haven't already paid dearly for the engine. Rotax is making Lycombing and Continental look cheap in the long run. It goes on and on.
    Dale

  • Re: TBO Extension clarification, please!

    by » 12 years ago


    Hi Adam,

    From the info in your post it looks like that engine would qualify for the extended TBO. You need to replace a couple of minor parts for about $40 and it takes about 5 minutes. You need to replace the oil pressure plug screw and oil pressure spring and I would just go ahead and put in the new oil pressure regulator cone or mushroom as some call it. Adding the oil pressure cone will make the price about $75. The plug screw and cone are about $32 each and the spring about $8. The plug screw is located just left of the oil filter and on the bottom edge of the oil pump. If it is the old style plug it will be a thin hex head, yellow in color and a flat surface. The new style has a recessed head and is aluminum in color. The new cone looks like a metal mushroom with a hole in the top and that replaces the old ball bearing. It will help steady the oil pressure, make it more reliable and possibly give you a few more psi in pressure. You won't pour oil out the hole when you remove the plug screw, but it will come out so have a rag handy and have the new parts together and when the old parts comes out just slide the new ones up in place as a unit and safety wire.
    Absolutely make sure you document this in your logbook with the SB number and part numbers installed.

    Roger Lee
    LSRM-A & Rotax Instructor & Rotax IRC
    Tucson, AZ Ryan Airfield (KRYN)
    520-349-7056 Cell


  • Re: TBO Extension clarification, please!

    by » 12 years ago


    Thanks Roger,
    I know about the new oil plug screw and spring; the instructions are laid out pretty clearly in the "Fluctuating Oil Pressure" video here on ROAN. That's one of two required mods by SB-912-057, the other is the crankcase replacement. I was trying to figure that part out. Are you saying that this engine does not need a replacement crankcase, only the oil pressure regulator upgrade?

    Two more questions. Should I purge the oil system after replacing the relief ball/piston? (Once again, the instructions are vague, they should end each procedure that requires purging with "purge oil system in accordance with <book, chapter and verse>")

    Second, should my logbook entry resemble: "Replaced oil relief plug screw, spring and ball with screw part no. ###, spring part no. ####, and piston part no. #####, TBO increased to 2,000 IAW SB-912-057?" If not, how should the entry be phrased?

    Thanks again,
    Adam

  • Re: TBO Extension clarification, please!

    by » 12 years ago


    Hi Adam,

    Your engine serial number is out past the affected engine serial numbers and your engine has the newer crankcase. So you are good to go there. You must replace the oil plug screw and spring, but should go ahead and do the oil cone too. If when you take out the old parts and immediately put the other in without sitting there and letting all the oil drain out then you don't need to do a purge because you shouldn't loose more than a few tablespoons of oil. So have the new parts in hand and assembled and when you unscrew the old parts just let them drop and put the new ones in place. Just takes a second.

    The entry in the book is fine, but you might note that it was safety wired and torqued to 15NM or
    11 ft/lbs. too. You can use IAW or say it meets all the requirements of the Rotax SB ##### along with the rest of your sentence. Either way it works.

    Roger Lee
    LSRM-A & Rotax Instructor & Rotax IRC
    Tucson, AZ Ryan Airfield (KRYN)
    520-349-7056 Cell


  • Re: TBO Extension clarification, please!

    by » 12 years ago


    Roger
    This sounds great to me. A 2000 TBO upgrade for less than $500. I want one. I have a 912 UL 100hp SN #5652111. Is it eligible for the upgrade?

    Tony

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