A320
Maintenance Powerplant; Maintenance Airframe
Communication Breakdown; Confusion; Training / Qualification
Deviation / Discrepancy - Procedural Published Material / Policy
Lead Mechanic assigned myself; Aircraft Maintenance Technician (AMT) X and two other AMTs; Y and Z; to Task Card XXX002 with attached Engineering Change/ Repair Authorization (EC/RA) to secure and torque the R/H main landing gear side stay bushing. Lead Mechanic went to Hangar-B to secure a torque wrench; I cleaned and prepped the side stay and the attach points on the main landing gear. AMT Y ordered the sealant needed for the job. We briefly reviewed the paperwork with [Lead Mechanic] and he told us the torque was 500 foot pounds. We started with 440 foot pounds but could not get any of the tabs to line up. I think we advance the torque setting to 480 foot pounds one time and could not get any tabs to line up. We then advanced the torque setting to the maximum of 500 foot pounds and still could not get any tabs to line up. We backed off the nut and re-torqued it at least 3-4 more times with an inspector present and were never able to align any of the tabs. We discussed our dilemma with the midnight shift supervisor and he turned over the job to midnight shift Mechanic X. Midnight AMT X reviewed the paperwork and pointed out that the paper read 500 lbf. in. It was obvious to us at that point that we had over torqued the side stay bushing. I believe that lbf. in (pounds force inches) is very confusing and led to our mistake in applying the proper torque for the job. Perhaps lb.in. (pound inches) or spelling out foot pounds or inch pounds would be clearer.
An Aircraft Maintenance Technician (AMT) reports how misinterpretation of an A320 aircraft Job Card reference contributed to the right-hand Main Landing Gear (MLG) side stay bushing retaining nut having a final torque twelve times greater than specified. Issue involves Airbus abbreviations for Pounds Force Inches (lbf) (in.) versus more common reference of lb. in. for Foot Pounds inches.