According to sources within PIA, the American authorities have notified them through a letter that the passengers coming to us via PIA flights will undergo an additional security check at the Manchester airport before departing for New York.
This additional security check will add more than six hours to the flights, which will increase various costs and expenses of PIA.
Speculations are that these restrictions have been imposed on PIA in the wake of Pakistan's decision to shut down all NATO supply routes after they attacked and martyred 24 Pakistani soldiers on the Pak-Afghan border, a few months ago.