Boeing 787 Dreamliner set for return to service 26 April 2013 Last updated at 22:01 Boeing engineer Rich Horigan explains how the battery problem was fixed An Ethiopian Airlines 787 Dreamliner is due to take off from Addis Ababa on Saturday morning, the first commercial flight by the Boeing aircraft since all 787s were grounded in January. The 50 planes around the world were grounded due to battery malfunctions that saw one 787 catch fire in the US. Over the past week teams of Boeing engineers have been fitting new batteries to the aircraft. This was after aviation authorities approved the revamped battery design. The Ethiopian Airlines flight is travelling to Nairobi in Kenya. Engineering team Each 787 has two of the lithium-ion batteries in question. In addition to new versions of the batteries which run at a much cooler temperature, the batteries are now enclosed in stainless steel boxes. These boxes have a ventilation pipe that directly goes to the outside of the plane. Boeing says this means than in the unlikely event of any future fire or smoke, it would not affect the rest of the aircraft. On Saturday I will board a simple, two-hour flight from Addis Ababa in Ethiopia to Nairobi in Kenya. It's not normally a flight that would make headline news around the world. But this journey is special, because it should mark the end of an incredibly damaging chapter for Boeing's flagship airliner. I'll be talking to passengers on board the flight, and it'll be fascinating to see how they feel about flying on a plane that was grounded across the globe only last January after one battery caught fire and another overheated, forcing an emergency landing. Boeing and its customers, who include British Airways, Virgin and Thomson, will be desperate to put the whole episode behind them. Boeing said it put 200,000 engineer hours into fixing the problem, with staff working round the clock. A total of 300 Boeing engineers, pooled into 10 teams, have in the past week been fitting the new batteries and their containment systems around the world. In addition to the 50 Dreamliners in service with airlines, Boeing has upgraded the 787s it has continued to make at its factory in Seattle since January. The Dreamliner entered service in 2011. Half of the plane is made from lightweight composite materials, making it more fuel efficient than other planes of the same size. The two lithium-ion batteries are not used when the 787 is in flight. Instead they are operational when the plane is on the ground and its engines are not turned on, and are used to power the aircraft's brakes and lights.