Date: 201507
Local time of day: 1201-1800
Location: ZZZ.Airport, US
Aircraft: Learjet 35
Operator: Air Taxi
Operating under: Part 135
Mission: Passenger
Flight phase: Parked
Aircraft component: Turbine Engine
Reporter organization: Air Taxi
Reporter function: Technician
Reporter qualification: Maintenance Airframe; Maintenance Powerplant
Human factors: Communication Breakdown; Situational Awareness
Second reporter function: Captain
Anomaly: Aircraft Equipment Problem Less Severe; Deviation / Discrepancy - Procedural FAR; Deviation / Discrepancy - Procedural Maintenance; Deviation / Discrepancy - Procedural Published Material / Policy
Detector: Person Maintenance
When detected: In-flight
Result: General None Reported / Taken
Contributing factors: Company Policy; Human Factors; Logbook Entry; Procedure
Primary problem: Ambiguous

Narrative: I had inadvertently returned a Learjet to service on many occasions with questionable inspection records for the T Piece Seal on an [engine]. The inspection record for this part was missing an inspector's stamp; but had been signed by the tech who had performed the inspection. I was alerted to the discrepancy by the overhaul facility and was later contacted by their vendor's FSDO. During our discussion; the inspector and I came to the conclusion that the part had sufficient life remaining to make it to the next Major Periodic Inspection (MPI) Inspection because it had been inspected previously; before installation on another engine; and had sufficient life remaining until a new inspection would have been due if the part had stayed on the original engine. I called my operator's Principle Maintenance Inspector (PMI) for concurrence and it was concluded that the logic was sound and we could continue to fly the engine until the next MPI Inspection was due. This afternoon; my operator's Director of Maintenance called me and to inform me that our Principle Operations Inspector (The previous PMI who had concurred with the vendors PMI had moved to another assignment) had questions about the airworthiness and documentation for this part. Together; the PMI and our Director of Maintenance determined that the aircraft would be considered not airworthy. In my conversation with the Director of Maintenance; he said that our PMI had determined the week before that this discrepancy did not call in to question the airworthiness of the part. I could not provide any documentation of the conversations with FAA inspectors from when this discrepancy had originally occurred. The FAA is not prepared to help us make a determination of the airworthiness of this part in any other way but to open an investigation.


Second narrative: I had inadvertently flown a Learjet on many occasions with questionable inspection records for the T Piece Seal on an [Engine]. The inspection record for this part was missing an inspector's stamp; but had been signed by the tech who had performed the inspection. I was alerted to the discrepancy by the overhaul facility; and was later contacted by their vendor's FSDO. During our discussion; the inspector and I came to the conclusion that the part had sufficient life remaining to make it to the next Major Periodic Inspection (MPI) Inspection because it had been inspected previously; before installation on another engine; and had sufficient life remaining until a new inspection would have been due if the part had stayed on the original engine. I called my operator's Principle Maintenance Inspector (PMI) for concurrence and it was concluded that the logic was sound and we could continue to fly the engine until the next MPI Inspection was due. This afternoon; my operator's Director of Maintenance called me and to inform me that our Principle Operations Inspector (The previous PMI who had concurred with the vendors PMI had moved to another assignment) had questions about the airworthiness and documentation for this part. Together; the PMI and our Director of Maintenance determined that the aircraft would be considered not airworthy. In my conversation with the Director of Maintenance; he said that our PMI had determined the week before that this discrepancy did not call in to question the airworthiness of the part. I could not provide any documentation of the conversations with FAA inspectors from when this discrepancy had originally occurred. The FAA is not prepared to help us make a determination of the airworthiness of this part in any other way but to open an investigation.


Synopsis: A Director of Maintenance and a pilot/mechanic reported that they had been advised of a missed inspection signoff for an internal engine component; but that in discussion with a FAA Principal Maintenance Inspector; the part was airworthy with the time remaining. Later; the conclusion was questioned by another Principal Maintenance Inspector and was under investigation.