Airworthiness Advisory Circulars - Part 6-70 - General advice
Part 6 - General advice
Use of Salvaged Parts
It has been brought to CASA's notice that there may be some salvaged aircraft parts being used by industry, especially aircraft parts that lack maintenance history. Many of these aircraft parts have been released to service after having been recovered from aircraft that may have been involved in accidents/incidents. The accident/incident may have caused damage or changed characteristics of the parts from those of the type design.
Since such items may not manifest any visual signs of damage, distortion or changed characteristics, a serious airworthiness hazard could result from their use without special precautions being taken as follows.
All such parts should be subject to competent assessment and inspection in the light of adequate knowledge of the circumstances of the accident/incident, storage and transport conditions, and with evidence of previous operational history obtained from valid airworthiness records, before overhaul and re-installation can be considered.
In particular, if a crash load is sufficient to take any part above its proof strength, residual strains may remain which could reduce the effective strength of the item or otherwise impair its functioning. Loads higher than this may of course crack the item, with an even more dangerous potential. A reduction in strength may also be caused by virtue of the change of a material's characteristics following overheat from a fire. It is therefore of the utmost importance to establish that the item is neither cracked, distorted or overheated. The degree of distortion may be difficult to assess if the precise original dimensions are not known, in which case there is no option but to reject the item.
The standard procedures appropriate to parts removed for overhaul following normal service life may not be sufficient for parts from salvaged aircraft. If the information in the manufacturer's manual, or other technical publications, is insufficient to deal with the considerations mentioned above then the manufacturer should be consulted for guidance.
If the manufacturer provides the additional information, and the item can be shown to meet this, then it may be returned to service.
In accordance with CAR30, a maintenance organisation must have written procedures for all work being performed. To maintain aircraft components that are salvaged there should be clear procedures detailing the additional precautionary steps applicable to such parts.