A recommendation by the National Transportation Safety Board may put miniature digital cameras in the air to detect mechanical problems in airplanes and to monitor flight crews. The agency suggested in February that all turbine-powered aircraft without flight data recorders be equipped with video cameras. The Federal Aviation Administration is reviewing the matter. The Air Line Pilots Association International, a labor union representing 55,000 pilots at 51 commercial airlines in the US and Canada, expressed concern with the move, which follows speculation on the causes of the Oct. 31, 1999, crash of EgyptAir Flight 990. In a statement before the US House Subcommittee on Aviation, Capt. Duane E. Woerth, union president, cited the "sensationalistic" use of cockpit voice data recorders following accidents and noted a history of abuse by employers.