Moving on from the prior post we considered about landing gear Life Limited Part (LLP) / Safe Life Item (SLI) awareness, to now consider what we might look for in the review of the back to birth (BTB) history.
We noted that we need to establish the history of the part since it was manufactured and as such we need for each time the LLP/SLI was removed and installed the details of these occurrences to create a full history record for that part.
This means for example that we require a certificate (FAA 8130 or EASA Form 1) for the part unless it came from a landing gear assembly in which case a statement from the SLI/LLP status for that assembly is acceptable to confirm the details at time of removal.
If the LLP/SLI was not replaced by an operator/lessee on an aircraft yet, then the part may well Reflect to the delivery documentation.
We also need to verify the applied limits for the parts themselves and this can come from the OEM (original equipment manufacturer). Awareness to SB/AD status can also be a consideration here.
In summary for every LLP/SLI we would typically look to verify the listing is correct from the OEM documentation (check items listed and applied limits). Then we check each part for required certification and verify that the certification history covers the item to its “birth” so you can verify the defined life of the item, comparing this to the limit you confirmed previously and determine the
remaining life. Finally, then once verified we ensure that the remaining life of the LLP is within
Landing Gear lease return conditions.