Last post we considered Airworthiness Directives (AD) and their embodiment date and noted this was the CRS (Certificate of Release to Service) date we would be using for this purpose.
We noted that some AD’s might be repetitive in nature; for example repeat an inspection every 500 flight cycles (1 cycle = a take-off and landing).
In the EASA system, the owner/CAMO is not required to keep the works orders or task cards commonly referred to as the dirty fingerprints (DFP)., i.e. the exact time of the performance of the maintenance which in our case is the AD action.
However, the owner/CAMO must consider the tasks with repetitive action having a calendar limit, where a significant lag could occur between the date of task performance and the date of the CRS; remember the prior post noted that “legally speaking” the CRS determines the effective date of accomplishment.
In such cases, the owner/CAMO must coordinate with the maintenance organisation the issuance of a release specifically and without undue delay to cover the particular task that is subject to a calendar limit when it has been applied, to avoid any distortion regarding limits associated with such repetitive actions or, as an alternative, record the date of AD accomplishment in the CRS.
In determining if a lag between the date of task performance and the date of the CRS is “significant”, engineering judgment and common sense must be used, and you should consider several factors such as:
How long is the time lag between the ‘due date’ (calendar time limit required for the next AD action) and the actual date of (planned) accomplishment?
For example, 2 days are significant for a monthly interval task, and obviously insignificant for a 5-year interval task).
What is the technical content (e.g., inspection for corrosion) of the AD task?
Where must it be accomplished, such as inside hangar, or outside, salty or otherwise erosive / corrosive environment)?
Any other factors may also be considered, affecting that single aircraft and/or operator etc.
You can see that the consideration for AD review is complex and important to review as its impact on maintenance requirements can be significant.
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