What happened
During a routine warehouse inspection of spare parts, an operator discovered that the EASA FORM 1 certificates accompanying certain fire extinguisher cartridge assemblies (PN 472001-01) contained inaccurate expiration dates. The certificates incorrectly indicated that the components were still within their service life.
Upon discovering this discrepancy, the operator ordered the immediate removal of the affected parts from the serviceable inventory and initiated a check of components installed on aircraft currently undergoing maintenance. The inspection revealed that the cartridges installed in the right engine of an ATR 7/2-200 had reached their expiration limit. While the components were manufactured in April 1997, the manufacturer-mandated service life of 10 years could not be extended.
Further investigation showed that functional tests had been performed on July 31, 2007, in an attempt to extend the component's usability. However, according to the Component Maintenance Manual (CMM) 26-21-34, such tests are only permitted when a malfunction is suspected and are not authorized for the purpose of life extension. Following this discovery, the operator audited the entire fleet and warehouse stock, identifying six additional expired cartridges. On one aircraft, all four installed cartridges were found to be past their service life. All expired elements were subsequently replaced.
The investigation
The investigation focused on how the inaccurate certification dates were generated and why the expired components remained in service. The investigators examined the maintenance records, the manufacturer's CMM, and the data management practices between the operator and the maintenance organization. The inquiry established that the error stemmed from performing unauthorized functional tests to bypass expiration limits and that both the operator and the maintenance organization were utilizing the same computer system to track component life cycles, which facilitated the oversight.