If members of the embattled Metropolitan Washington Airports Authority board still had any doubts about how much their unethical and secretive behavior has eroded public confidence in their continued stewardship, those doubts were dispelled Tuesday. In an unusually caustic letter signed by U.S. Transportation Secretary Ray LaHood, Virginia Gov. Bob McDonnell, Maryland Gov. Martin O’Malley and D.C. Mayor Vincent Gray, MWAA board members were given a laundry list of reforms that “must be instituted immediately.” They were also ordered to cooperate fully with the new federal accountability officer specifically assigned to monitor them.