The crew on Tuesday's flight indicated the problem's possible location, radioing the tower while on approach to New Orleans airport to request that first responders check for discoloration or dripping plastic in an area behind the wing known as the aft electrical equipment bay, where many of the aircraft's electrical power systems are located.

United said there was no indication of fire on the aircraft. United officials were focusing their investigation on a generator on the plane, according to a person familiar with the situation.

Eric Erickson, a finance consultant from Houston, said that just over an hour into the flight, the lights flickered and his seatback television froze and had to be rebooted. "I then noticed we were making a long right-hand turn" to New Orleans, he said.

The 787 uses significantly more electrical power to run the aircraft's systems than most other jetliners, which is seen as one of the jet's biggest technological leaps from previous models, but also adds greater complexity to manage the new design.

In November 2010, Boeing suffered an in-flight fire in the same electrical bay while on approach to Laredo, Texas, during a test flight. The incident resulted in a redesign of a power-control panel and parts of the jet's electrical software that took several months.