Important information relating to Civil Aviation Safety Authority (CASA) airworthiness directive AD/PZL/5 was not contained in CASA’s airworthiness directive file, but on other CASA files with no cross-referencing between those files. This impacted CASA’s future ability to reliably discover that information and make appropriately‑informed decisions regarding the airworthiness directive.
A search of the ATSB occurrence database identified no occurrences where separate, non-referenced AD files were found to have contributed to the occurrence. The ATSB considers that although some risk remains, it is as low as reasonably practicable.
On 7 October 2015, the CASA advised the ATSB that,
…historically CASA Airworthiness Directive (AD) files were used to manage the administrative side of AD publication and the technical assessment aspects were stored separately. Since 2009 CASA has used an electronic filing system and the AD procedures manual mandates an individual file for each AD. This allows CASA to include all the background information and any further correspondence on the same file. Any alternate means of compliance and exclusions to the AD are also stored in the electronic file, and the files are electronically linked in accordance with the AD procedures manual.
The ATSB accepts that the changes already made by CASA have adequately addressed the safety issue for those files started after 2009.
The safety issue may still remain for those airworthiness directives issued prior to 2009. However, the ATSB acknowledges the practicalities in attempting to identify AD-related material in a large number of files and consolidate the applicable information into a single AD file.
