BY CAROL ROSENBERG

 Worried about the safety of Havana's state-run Cubana airlines, the State
 Department is forbidding U.S. diplomats and other government officials from
 traveling around the island on internal commuter flights.

 The news comes as charter air services from the United States are gearing up for
 one of the heaviest Christmas travel seasons ever between Miami and the island.
 The charters do not use Cuban aircraft. But, once there, any visitor seeking an
 internal flight would have to take a now-banned Cubana de Aviación aircraft.

 An advisory by the State Department dated Dec. 1 revealed the ban and suggests
 that ``Americans who are required to travel by air within Cuba may wish to defer
 their travel or consider alternate means of transportation.''

 Called a Consular Information Sheet, the Cuba advisory updated an earlier Sept.
 14, 1999, State Department information sheet that routinely describes country
 conditions for U.S. travelers.

 A U.S. diplomat, who asked not to be named, said the State Department issued
 the advisory because once the agency banned U.S. officials from taking Cubana
 flights federal law requires that the public be notified as well.

 ``We believe that Cubana de Aviación is unsafe, and that's new,'' the official said,
 citing concerns about maintenance, spare parts and the state of the airline's
 planes, some of which are vintage Soviet-era Ilyushin aircraft.

 Cubana aircraft have experienced several serious accidents in the past 18
 months. On Dec. 21, 1999, a Cubana-leased DC-10 crashed on a runway in
 Guatemala City, killing 25 people. Four days later, a Russian-built Yak-42
 Cubana plane crashed about 90 miles west of Caracas, in Valencia, killing all 22
 people on board.

 Also, in September, a Cubana pilot died of a heart attack while commanding a
 flight between Bogotá, Colombia, and Havana.

 His copilot took charge of the flight, with 155 people on board, and successfully
 landed it in Barranquilla in northern Colombia.

 U.S. officials are partially stymied in their ability to assess Cubana's
 airworthiness because the U.S. embargo on Cuba prohibits Cubana aircraft from
 entering the United States, meaning the Federal Aviation Administration has no
 access to the airline's records or data to independently track maintenance
 activity.

 Ironically, the same advisory issued by the State Department said that the FAA
 recently completed an information exchange with Cuba's Civil Aviation Authority
 and found that the four Cuban airports served by U.S.-based charters have
 suitable security procedures that meet the standards of the International Civil
 Aviation Organization. The four airports are José Martí International in Havana, and
 smaller airports in Holguín, Camagüey, and Santiago de Cuba.

 Cubana began in October 1929 as Compania Nacional Cubana de Aviación
 Curtiss. By 1945, its name was shortened to Compania Cubana de Aviación, with
 its first international flights using DC-3 aircraft to Miami.

 After the 1959 revolution, the now state-run business sold its Western-type
 aircraft and replaced them with Ilyushin, Tupolev, Antonov and Yakovlev, or Yak,
 models.