I have a confusion regarding TBO of Rotax engine. As stated in Line Maintenance Manual Chapter 05-10-00 TBO is the approved length of operation under normal condition. Rotax 914 engine was purchased back 2 year ago as a backup but was not used/installed. It was preserved as per instruction given in Operator Manuals. Engine is installed on airframe this month so my question is what will be the TBO of this engine and do it need any sort of maintenance.

  • Re: TBO of preserved Rotax Engine

    by » 3 months ago

    Assuming a newer engine with a 2000hr/15yr TBO;  The 2000hrs will be Hobbs operating time and the 15-year clock started the day the engine was assembled, not installed.
    The seals and O-rings have been aging in the box.
    The recommended 5-year rubber parts replacement will be due in 3 years.

    Rotax recommends that any engine not put into service within 2 years be overhauled before use, but that will be your call.

    Bill Hertzel
    Rotax 912is
    North Ridgeville, OH, USA
    Clicking the "Thank You" is Always Appreciated by Everyone.

  • Re: TBO of preserved Rotax Engine

    by » 3 months ago

    Not so sure about that...

    Rotax states a general overhaul is required after a defined time or hours "since initial start of operation"


    Therefore the TBO starts "since initial start of operation"

    It does NOT say from date of manufacture, or date of install.

    It does later state that if the engine maximum possible storage is 24 months.

    Therefore I read that to mean you can store for up to 24 months then TBO starts from first start.

    Although the rubbers etc will be a little older, the main cause of rubber deterioration is heat, and a stored engine does not get "running hot"



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