UPDATE #UA55 had mechanical issues related to autotrottles and navigation/sensor anomalies.
UPDATE 13:54 UTC United #UA55 to Newark landed safely at London Heathrow.
UPDATE 13:20 UTC United #UA55 from Paris CDG to Newark is diverting to London Heathrow (LHR).
BREAKING United #UA55 from Paris CDG to Newark is declaring an emergency. Live: http://t.co/GiyJYRojis pic.twitter.com/cgsuocxwJb
— AirLive.net (@airlivenet) September 28, 2015