In the Metropolitan Opera production of Berlioz’s “Troyens” two harnessed dancers representing Dido and Aeneas take flight in an aerial ballet. But don’t look for it when the opera returns to the Met stage on Dec. 13.

The duet has been grounded for safety reasons because of outmoded, worn-out stage machinery. It’s just one example of why the Met is embarking on its largest renovation since moving into Lincoln Center in 1966. It will be a $60 million job over the next five to seven years but lacking in the flashy type of rebuilding that has remolded Lincoln Center recently. This renovation concerns the guts of the place, replacements or upgrades for the Met’s internal organs: the flies, lighting, stage lift, air circulation and internal communication systems.

The Met’s technology has fallen behind European opera houses, where many of the directors bringing new productions to New York are used to computerized controls that produce precise results for increasingly spectacular shows. At the Met stagehands still twiddle dials, plug in cables, consult numbered charts and use a lot of muscle.

“It’s really old-fashioned technology,” the Met’s general manager, Peter Gelb, said in an interview this week. “We work with it. We use it. But it has to be modernized. It’s safe without limitations in our use of it, but at some point it could fall apart. We’re not waiting for that day to happen.”