Assuming they actually have that certification. That's the kicker. I am happy with certification by a reputable organization (FAA or EASS,) however we're assuming those certifications. Just because Lufthansa co-owns the venture doesn't mean they spent the money to send all of those mechanics to an accredited certification program. The Lufthansa CEO is known for being cheap -- he's on record complaining about (and initially refusing to install) full flat business class seats in the new A380s because of the lost revenue from the extra space they would have required. I fly Lufthansa about a dozen times per year and generally feel confident about maintanence, however if the reason for this is cost savings, there's a real danger of even minor communications issues becoming deadly.