KLM Boeing 747 near Los Angeles on Nov 18th 2017, engine vibrations

A KLM Boeing 747-400, registration PH-BFS performing flight KL-602 from Los Angeles,CA (USA) to Amsterdam (Netherlands), departed Los Angeles with a delay of about 2.5 hours and was enroute at FL290 about 320nm northeast of Los Angeles when the crew decided to return to Los Angeles due to an issue with an engine (www.aeroinside.com) 기타...