Speaking to the Official Club Website, the former Luton Keeper said: "It's not been the best day I've ever had.
"I'm on holiday with my family at the moment but was due to fly back to Britain today and travel to Sunderland to sort out the last few details.
"I got to Malaga airport to catch a flight at 10.00am but the plane broke down and I had to sit in the airport waiting for the problem to be solved.
"It got to around 6.00pm and that was enough for me. I'm back with my family and will stay overnight in Spain before hopefully catching a flight in the morning to Newcastle.
"It looks like everything will be finalised on Tuesday and I'll be signing for Sunderland then."