Korean Air

I'm YS Seong, Engineer in Korean Air.Let us begin by saying that we appreciate your devotion for safety of air traffic system.I would like to comment about the 2012-NM-054-AD.The notification said the proposed AD would require installing enclosure trays to contain debris in certain ELMS Panels and replacing the certain ELMS contactors.Additionally, we are aware of lots SB had been released to the operators such as installing the cooling duct & internal inspection of panel.I agree that these service bulletins are the proper retrofit to prevent the smoke & fire event from ELMS. So KAL also sincerely implemented the installation of cooling duct and tray enclosure at the ELM Panel in spite of the lack of labor hour and the trouble of aircraft schedule plan. Because we thought these retrofits are the most countermeasure for keeping the safety of passengers and crews. However, Although the operators has implemented the tray and cooling duct retrofit at the ELM System, It is not acceptable that the replacement of ELMS Contators is required by the proposed AD. Originally, SB 777-24-0112 is the optional and the ELM contactors which can be gradually replaced by attrition base are not mandatory item.If the propose AD is required to replace ELM Contactors, the burden of high cost is much influence to the operator unnecessarily. In addition, the Boeing had mentioned the ELM contactor is not necessary to be replaced by SB 777-24-0112 in the ELM System which had been installed by SB 777-21-0117/-0114.To sum up, we would like to suggest that the proposed AD just has the tray enclosure and cooling duct modification, not replacement the contactors. So we request FAA to reconsider the replacement of contactors is optional to the operators who has implemented the retrofit of tray enclosure and cooling duct at the ELM system.Thank you for concern about the proposed AD and your cooperation for safety of Air Traffic System and look forward to your keen attention to this matter.