Lycoming TBO (Time Between Overhaul). Your questions answered!
We get a lot of questions about TBO times for all the different aircraft that we sell (most of which have Lycoming engines!) For reference, we thought that we would put together a brief summary of the Engine TBO times for Lycoming engines, based on the Lycoming service instruction April 24th, 2020. Of course, your LAME and your aircraft documentation (including run-out sheets and Maintenance logs) will answer the TBO questions about YOUR aircraft, but this guide should assist if you're looking to buy - and need to verify the details presented by the Seller.
1. All engine models are to be overhauled within twelve (12) calendar years of the date they first entered service or of last overhaul. This calendar year time period TBO is to mitigate engine deterioration that occurs with age, including corrosion of metallic components and degradation of non-metallic components such as gaskets, seals, flexible hoses and fuel pump diaphragms.
CAUTION CALENDAR YEAR TBO IS BASED ON ACCELERATED TESTING AND OVERALL FLEET SERVICE DATA. LOCAL CLIMATE CONDITIONS, STORAGE CONDITIONS, FREQUENT EXTENDED PERIODS OF INACTIVITY, PRESERVATION TECHNIQUES USED DURING INACTIVE PERIODS, AND FREQUENCY OF OIL CHANGES CAN AFFECT CORROSION OF METALS AND DEGRADATION OF NON-METALS.
2. OPERATING HOUR TIME PERIOD TBO
Operating Hour TBOs for fixed wing aircraft are in Table 1 and for rotary wing aircraft are in Table 2. These TBOs are to mitigate engine deterioration that occurs during normal operation such as wear and high cycle fatigue of metallic components.
CAUTION OPERATING HOUR TBO'S ARE BASED ON ACCELERATED TESTING AND OVERALL FLEET SERVICE DATA. BECAUSE OF VARIATIONS IN THE MANNER IN WHICH ENGINES ARE OPERATED AND MAINTAINED, LYCOMING CANNOT GIVE ASSURANCE THAT ANY INDIVIDUAL OPERATOR WILL ACHIEVE THE OPERATING HOUR TBOS IDENTIFIED HEREIN.