A319
Maintenance Airframe; Maintenance Powerplant
Maintenance Technician 14
Troubleshooting
Aircraft Equipment Problem Critical; Deviation / Discrepancy - Procedural Maintenance
General Maintenance Action
Aircraft; Human Factors
Crew reported at XA:45 that they had a slow to accelerate spool up on #2 engine. Also on descent they noticed an unusual vibration. Within minutes thereafter I inspected the #2 Engine for damaged blades N1 and Exhaust. I noticed looking through the slim gap between the thrust reverser halves and the core of the engine bottom 6 o'clock position; there was a plug with a long shaft laying at the rear. I alerted the crew to hold boarding at about XA:52 because I would need to open the thrust reverser halves to inspect further. Originally I began looking at the borescope plugs but all plugs were installed and safetied. I noticed looking at the 5th stage check valve; that it was missing a plug as pictured. I inserted the plug and it was a match for the missing through bolt. I had another mechanic assisting me at the time; he took pictures and sent to Maintenance Control to alert of the finding and request support for operational checks once bolt was reinstalled. Maintenance Control notified me that a FADEC Motoring check done through the MCDU would be satisfactory. There was no difficulty reinstalling the through bolt and from the picture I have seen; it appears the bolt did not align with the flapper due to its failure and misalignment. I did not remove the valve for reinstallation of this through bolt; and in hindsight I should have done this as a precaution to inspect the valve for damage. I also would have been able to confirm that the butterfly indeed was aligned with the through bolt. Lesson learned! Bolt was installed; engines closed and secured and motoring check was satisfactory. Notified Maintenance Control approximately XC:00 work was complete and aircraft returned to service at XC:15 approximately.
A319 Maintenance Technician reported finding a check valve was missing a through bolt on an engine that was slow to spool.