LONDON (AP) -- British pilots won assurances from the government Tuesday that they will be told when armed sky marshals are on board their flights, but demanded to know where the guard is seated and to be able to maintain regular contact. Meanwhile, a British Airways flight from London to Washington, which was canceled twice last week over security fears, was delayed for the fourth consecutive day Tuesday because of U.S.-requested security checks. On Tuesday, British Air Line Pilots' Association said it would advise its members - nearly 90 percent of Britain's 9,200 commercial pilots - not to fly with...