Date: 201407
Local time of day: 1801-2400
Location: ZZZ.Airport, US
Light: Night
Aircraft: DC-10 30
Operator: Air Carrier
Operating under: Part 121
Mission: Cargo / Freight / Delivery
Flight phase: Parked
Aircraft component: Exhaust Pipe
Reporter organization: Air Carrier
Reporter function: Technician
Reporter qualification: Maintenance Airframe; Maintenance Powerplant
Human factors: Confusion; Communication Breakdown; Situational Awareness
Anomaly: Aircraft Equipment Problem Critical; Deviation / Discrepancy - Procedural Maintenance; Deviation / Discrepancy - Procedural Published Material / Policy
Detector: Person Maintenance
When detected: Other During Maintenance
Result: General Maintenance Action
Contributing factors: Human Factors; Chart Or Publication; Manuals; Aircraft
Primary problem: Human Factors

Narrative: Our Dayshift was called out to a DC-10 aircraft at the gate; July 2014; to cut the tack welds on the studs in the Turbine Rear Frame (TRF) struts on the Number 3 Engine. Dayshift cut the tack welds and assisted the line mechanics with removal of the studs. Line Maintenance then replaced the studs; during shift change at our shop. After shift change; late afternoon; we were called back to the aircraft to tack weld the studs in the strut per the repair. All of this was accomplished per the General Electric (G.E. Engine Manual 72-58-01; Repair 006; Figure 902; Stud Installation Subtask 72-58-01-310). After which I returned to update the repair in the logbook; and then called Quality Control (QC) to verify they knew about; and were going to do; a Fluorescent Dye Penetrant Inspection (FPI) on the welds as the repair called for. At this time; QC brought to my attention that we could not use the repair [procedure] from the Engine Manual without an Engineering Authorization (EA) from Engineering; because we were not in a shop environment; but was on the flight line. At which time I went to Engineering to ask about an EA. Engineering told me first to use the reference out of the Aircraft Maintenance Manual (AMM) that was given. I responded with; we could not use the AMM reference because it does not reference tack welding the studs in the strut. At which time I requested an EA and an Engineering Request (ER) had [already] been turned in from Line Maintenance requesting an EA (via an ER) to use the Engine Manual reference. Engineering said they would cut an EA and would attach it to the ER as soon as they could. After midnight; we received the EA from Engineering. At that time; I pulled up the aircraft on our maintenance computer; to check the status. It stated that Line [Maintenance] had put [the engine] back together with the aircraft and was getting ready to call the aircraft up [to release for service]. I then called QC to see if they had done the FPI; which they had not. So I called Maintenance Control to make them aware that the plane was back together and the FPI had not been completed. Maintenance Control told me at that time; Line Maintenance had done the FPI Inspection; it had checked good and the job was complete. I told Maintenance Control at that time; that the logbook had not been updated for the FPI and that I had an EA for the job; also; what did they want me to do with it? I was told by Maintenance Control; that the EA was a blanket EA and I didn't need to do anything with it. At this time it was at the end of the shift; I went home. I came in the next day and discussed the previous night's on-goings with QC.[Concerns were] that everyone not being on the same page; as far as what manuals can be used for what job. The General Maintenance Manual (GMM) states what the approved manuals are that can be used; but it does not break them down to specifics as far as when certain manuals can and cannot be used. I.E.. Engine Manual in a shop environment /or; not in a shop environment. There needs to be something put in print explaining to everyone when certain manuals can; and cannot; be used. Because it depends on what you read; how you interpret what it says; and who says what it is at this point. Just like the debate on when you can; and when you cannot use the Component Maintenance Manual (CMM).

Callback: Reporter stated he is a machinist with FAA Airframe and Powerplant (A/P) certificates. The struts are attached to the 'Hot' section of the G.E. CF-6 Engine where the exhaust cone in the center is attached to the engine aft section using threaded studs that secure the center cone nozzle to the Turbine Rear Frame (TRF). There are three configurations for repair/replacement of the studs. His Air Carrier used the Tack Weld procedure as an alternative for installing and securing the new studs to the aft frame of the TRF; because they did not have the equipment or fixtures to perform the other two procedures; and also because the studs were previously installed using the Tack Weld procedure.Reporter stated confusion arose about whether or not the G.E. Engine Manual could be used for a repair procedure on the Line at the gate; since the aircraft was not in a hangar; or the engine in a shop environment; which is required per the Engine Manual. Adding to the confusion was the belief the Fluorescent Dye Penetrant Inspection (FPI) of the new tack welds he did; had been accomplished by Line Maintenance before the exhaust cone was re-attached to the engine TRF. The aircraft was released even though he told Maintenance Control the logbook had not been signed-off; stating the FPI had been accomplished on the tack welds for the new studs. After review of the paperwork; his Air Carrier brought the aircraft back to their Maintenance Base and the entire process was redone per the Engine Manual and Inspection requirements.Reporter stated some clarification came about after their rework of the stud installation and tack welds. Their General Maintenance Manual (GMM) lists what manuals are approved for use to perform repairs and does exempt Line Maintenance from the requirement that use of the Engine Manual or Component Maintenance Manual (CMM) for repairs has to be accomplished in a shop environment. Repairs to an engine on-wing are acceptable; using their Engine or CMM manuals as long as they use the entire repair procedure and not attempt to piecemeal sections of the repair procedure.



Synopsis: An Aircraft Machinist describes his involvement with an on-wing tack welding of new studs installed at the aft flange of a G.E. CF-6 Engine Turbine Rear Frame (TRF) Assembly for a DC-10 aircraft. Aircraft was released without a required Fluorescent Dye Penetrant Inspection (FPI) being accomplished on the new tack welds and signed-off in the logbook.