There is a new sight buzzing around a Ford engine factory in London: drones.

The second-largest U.S. automaker is now using drones to perform key inspections in difficult-to-reach places around the Dagenham Engine Plant. The unconventional move saves Ford considerable time and money and brings several other advantages, executives say.

In the past, plant managers used to have to shut down the factory at least once a year to perform risky and time-consuming inspections on high-up structures, parts of the factory's roof and other hard-to-reach places. The drones allow the Michigan-based automaker to conduct safety inspections without shutting down production.

The drones also give Ford a more objective plant maintenance record, preventing arguments over the diagnosis and possible solutions to problems, said Pat Manning, a machine production manager for the EcoBlue diesel engine at the plant, where it's code named Panther.

"The video images are fantastic and are a great tool for us," Manning said.

One of the most common inspections involves overhead structures known as gantries. These are long linear frames suspended near the roof and support a track that shuttles a robotic arm around the plant. The arms on these tracks are what pick up parts in one place and feed them into the machines along the factory floor.