Limited Life Parts & Tracing the history – aircraft leasing

The Limited Life Parts & Tracing the history for aircraft leasing is an important part of every review, not only for compliance, but also for two key reasons:


Timescale to repair.

Some parts on an aircraft or commonly aircraft engines and landing gear are known as Life Limited Parts (LLP) or Safe Life Items (SLI). Very simply these are parts which have a defined life regardless of condition upon inspection.

When we start to review the SLI/LLP parts then we need to start at the beginning of the parts life – this means from when they are New. The tracing of the parts history is commonly referred to as a Back to Birth check.

If the item was “used” before, or “not new” then commonly it is referred to as “Part Life” meaning that it is partially through its defined life.

When a part life item is installed, we still need to see (BTB) Back to Birth details for the item. It is a little more complicated than a new item as we need to confirm the parts history through the records supplied.

When reviewing a part life item, you should have a certified statement from the previous operator(s) detailing the Hours/Cycles accrued during their ownership/use. We need to establish the CSN (Cycles Since New) and so if more than one operator you may have more than one statement.

A statement detailing what the LLP was installed on (details of the major component it was removed from such as an engine or landing gear) should be provided.

There are also some mandatory documents that we would look for such as incident or accident clearance statements for that part as and when it can move between operators, noting this can include ferry flights.

The history of the part determines its remaining value and as such the lease transition can have many items or parts on an aircraft that while they can be airworthy, it might not meet the lease return conditions; typically, the costs are high.

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