A Line Mechanic reports a company MD-11 was released for service with an unapproved cockpit portable oxygen bottle smoke/mask installed; even though carrier's IPC Stores (Illustrated Parts Catalog) noted the part was not effective on any current fleet type.

Narrative

Company AMT (Aircraft Maintenance Technician) removed and replaced a portable oxygen mask on an MD-11 aircraft. The AMT found the mask scratched during a Maintenance Inspection. After reviewing the IPC (Illustrated Parts Catalog); the AMT requested (Part Number) P/N XXXC1 from Parts Stores as required by IPC 35-31-01-01. Rather than provide the P/N requested by the AMT; the stores personnel provided P/N XXXA1; the same P/N that was removed from the aircraft. The following notation was documented in the IPC under P/N XXXA1: 'Procurement Notes: This P/N is not effective on any current fleet type. Do not buy or repair part. Please surplus any off units.' It's unclear why the part [smoke mask] remained in Company's system; when the Company was well aware the part was not effective for any current fleet type. It was also unclear how the wrong part was installed on the aircraft to begin with. The Company's Irregularity Report also failed to mention that the part that was removed from the aircraft was not effective for any company aircraft.[Later] I spoke with FAA Inspector who confirmed the wrong part was installed on the aircraft and the issue was currently under investigation. Although the part removed from the aircraft was not approved for any Company aircraft; it was my understanding no action has been taken to determine if the unapproved part is installed on any other Company aircraft or if they remain in Company's inventory. There appear to be many contributing factors contributing to this event. I hope the FAA will take all factors into consideration (i.e.; unapproved parts not removed from Company's inventory) and provide immunity for any possible violations for all Certificated Airman/employees involved. I also hope a fleet campaign will be done immediately to determine if any unapproved smoke goggles remain on Company aircraft.