What’s that you’re doing, Mr. Rosengrün?

What's that you're doing, Mr. Rosengrün?
© Sonja Brüggemann/LH Technik

David Rosengrün, 35,

Engine technican

has been with Lufthansa Technik in Hamburg for 18 years


“I’m repairing a damaged thread on an aircraft gearbox. The so-called stud bolt, which is ordinarily secured here, is loose and just keeps spinning. That may not sound like a big deal, but the repair calls for special know-how: Even the tiniest fault in this special thread can end up damaging the entire gearbox, which would mean that the repair would take up to ten days instead of just a few hours. I have even been flown to China on occasion because they didn’t have anyone with the right expertise in the workshops there. To repair the damage, I first have to drill open the hole with the damaged thread a little more, up to a diameter of 10.5 millimeters. This makes it too wide for the slim 6-millimeter stud, but I solve this by cutting a new thread into it and screwing a matching aluminum bushing with a six-millimeter threaded bore into the new hole, thus ensuring that the original bolt holds perfectly again.”