RAM has noted that well maintained aircraft that are in compliance with AD 75-23-08 have posed no problems. However, various discrepancies are obvious for those aircraft which not been properly inspected and maintained per AD 75-23-08. Furthermore, attempts to inspect and determine the wall thickness is not feasible. Additionally, RAM believes that there is no material advantage of inconel over stainless steel as a material of choice. In fact, there are no 100% inconel systems available. It should be noted that many maintenance facilities DO NOT have the appropriate experience, expertise or approved data to make these inspections properly resulting in aircraft being returned to service in an unacceptable condition.