The £37million man from Chelsea is due to take a helicopter from Battersea in south London later today and fly straight to United's training ground, where a temporary landing pad has been arranged.
The Daily Mail says he has been told to get ready to leave his apartment in Chelsea at short notice and travel to a helicopter flight base in nearby Battersea.
Once in Manchester, the Spanish playmaker is due to have a look round United's impressive training base, meet manager David Moyes and then head to the Bridgewater Hospital near the city centre for a medical.
United do not have a game this weekend as they are already out of the FA Cup but it is hoped that Mata will train with his new team-mates on Friday and be ready for next Tuesday's home game against Cardiff in the Barclays Premier League.
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