Lycoming Engine TBO
MrAverage
You don't say what your interest is in this discussion, however, a few points to note from a QA viewpoint.
1. Whatever the AMO might say, it is the responsibility of the operator to ensure that all maintenance is properly performed, on-time and correctly recorded.
2. In order to assist you when asking for this sort of assistance, always request that primary source documents are identified. In this instance the most important is Lycoming Service Instruction Number 1009. Make sure that you ascertain that your AMO provides a copy of the latest Issue. I am now retired but the last issue I saw was 1009AS in 2006. Read the document very carefully as the type of operation can affect the final TBO figure.
3. Once you have established the Lycoming figure, you can then refer to other documents, e.g. if you have a UK AOC, then CAP 747 will guide you. It is available on line to download for free from the CAA.
4. Normally, a TBO like this will have to be specified in your maintenance programme because it is "variable" according to your type of operation. Where a Lycoming life is extendable, CAP 747 normally specifies additional maintenance at 100 hour intervals once the "normal" TBO has been reached and surpassed.
Note:
One final thought and an important one. Some organisations wish to run their engines well beyond the normall permitted TBO's. This, as I am sure everyone will agree, can only be done with the approval of both Lycoming and the relevant authority. The big risk with this is that the operator becomes legally responsible and has no means of off-loading any responsibility in the event of a major incident or accident. Not normally an issue because the effort involved in increasing a TBO, as opposed to an extension, must be more trouble than it is worth.