BY ANA ACLE AND ALFONSO CHARDY

 Three hours before two Brothers to the Rescue aircraft were shot down, the U.S.
 launched fighter jets from Homestead Air Force Base to respond to the presence
 of Cuban MiGs flying toward the United States, according to government
 documents released Thursday by Brothers to the Rescue.

 But when the Cuban MiGs were launched again later that same day, resulting in
 the fatal clash with the Brothers' Cessnas, no U.S. jets were scrambled and two
 F-15s on the runway at Homestead were told to back down -- at precisely the
 moment of the attack.

 Thursday, a spokesman for the North American Aerospace Defense Command
 (NORAD) finally explained why: A duty officer for NORAD misinterpreted an order
 from NORAD'S commander in chief that the U.S. planes not be provocative and
 told the Southeast Air Defense Sector Command at Tyndall Air Force Base near
 Panama City, Fla., to take the Homestead planes off alert.

 That was not what NORAD's then-commander, U.S. Air Force Gen. Howell Estes,
 intended, according to NORAD spokesman U.S. Army Maj. Barry Venable.

 ``The guidance from the commander in chief was incorrectly relayed,'' Venable
 said. He did not have the name of the NORAD duty officer.

 The Southeast Air Defense Sector commander realized the mistake and ordered
 the planes back on alert 15 minutes later, but by then the Brothers to the Rescue
 aircraft had already been shot down.

 Why the U.S. planes went off alert at the very moment the MiGs were zeroing in
 on the Cessnas has been one of the enduring questions about the Feb. 24, 1996,
 shootdown, in which four people, including three U.S. citizens, lost their lives.

 Previously, government reports on the incident had referred only to a
 ``communication mix-up'' to explain why the U.S. planes went off alert.

 At a news conference Thursday, Brothers President José Basulto reiterated the
 claim he's made for years: The pilots could have been saved and the U.S.
 collaborated with Cuba.

 Basulto is demanding that presidential candidates George W. Bush and Al Gore
 declare their positions on pushing for a criminal indictment against Cuban leader
 Fidel Castro for the shootdown.

 ``We were denied the protection this government could have afforded us,'' Basulto
 said.

 But NORAD said Thursday that even if the F15s at Homestead had remained on
 alert they probably would not have been deployed to intercept the MiGs. ``We're a
 defensive organization against anything that comes into our sovereign air space,''
 U.S. Air Force Master Sgt. Larry Lincoln said.

 According to the documents Basulto released Thursday, on the day the Brothers'
 Cessnas were downed, U.S. F-15s and Cuban MiGs scrambled between 12:15
 and 12:45 p.m and came within 80 nautical miles of each other. The Cuban MiGs
 were seen at 12:41 heading back to their bases and the F-15s returned to
 Homestead at 1:06 p.m.

 The three Brothers planes, one piloted by Basulto himself, took off from
 Opa-locka airport five minutes later, flying south toward Cuba.

 As Brothers' planes approached the Cuban coast, Cuba launched two MiGs into
 the air. The time was 3 p.m.

 Radar sightings of the MiGs prompted the F-15 fighters poised at Homestead to
 go into a ``battle stations alert.

 Unexpectedly, however, at 3:20 p.m. the alert was called off.

 The first Brothers aircraft was shot down one minute later at 3:21 p.m.

 The second was downed eight minutes later at 3:28 p.m.

 Brothers members Carlos Costa, Armando Alejandre Jr., Pablo Morales and
 Mario de la Peña died.

 Seven minutes later, at 3:35 p.m., the alert for the F-15s at Homestead was
 resumed.

 At the time, U.S. military officials said the American interceptors were not
 scrambled to challenge the MiGs because the Cuban fighters turned back before
 reaching the boundary of U.S.-controlled airspace -- a zone marked by the 24th
 parallel in the Florida Straits, halfway between Key West and Havana.