Before 1996, approximately 6,000 large commercial transport airplanes were assigned a type certificate to fly up to without having to meet high-altitude special conditions. In 1996, the FAA adopted Amendment 25-87, which imposed additional high-altitude cabin pressure specifications for new-type aircraft designs. Aircraft certified to operate above "must be designed so that occupants will not be exposed to cabin pressure altitudes in excess of after any probable failure condition in the pressurization system". In the event of a decompression that results from "any failure condition not shown to be extremely improbable", the plane must be designed such that occupants will not be exposed to a cabin altitude exceeding for more than 2 minutes, nor to an altitude exceeding at any time. In practice, that new Federal Aviation Regulations amendment imposes an operational ceiling of on the majority of newly designed commercial aircraft. Aircraft manufacturers can apply for a relaxation of this rule if the circumstances warrant it. In 2004, Airbus acquired an FAA exemption to allow the cabin altitude of the A380 to reach in the event of a decompression incident and to exceed for one minute. This allows the A380 to operate at a higher altitude than other newly designed civilian aircraft.