KLM B744 at Amsterdam on Nov 10th 2014, rejected takeoff twice

A KLM Boeing 747-400, registration PH-BFY performing flight KL-643 from Amsterdam (Netherlands) to New York JFK,NY (USA), was accelerating for takeoff from Amsterdam's runway 24 when the crew rejected takeoff at low speed (about 45 knots over ground) indicating no assistance was needed and they wanted to rejoin the departure queue.

A passenger reported the captain announced they had aborted takeoff due to an indication they had determined to be a false warning.

The aircraft accelerated for takeoff from runway 24 again about 10 minutes later but again needed to reject takeoff at low speed, the aircraft vacated the runway.

The passenger reported the captain now announced that the indication appeared not to be false, one of the four generators was malfunctioning. The aircraft stopped on a taxiway waiting for clearance to return to the gate. About 10 minutes later the captain announced that maintenance had cleared the aircraft to cross the Atlantic on three generators, the business class would remain without power however.

The aircraft departed about 35 minutes after the first takeoff was rejected and reached New York with a delay of one minute.