Joined: 11 Dec 2005
|Posted: Thu Dec 19, 2013 1:15 pm Post subject: Two Different CAT II Minimums for Some Airfields
|Two Sets of Operating Minimums for CAT II
Two basic sets of operating minimums are established for CAT II operations. These are:
(a) Standard CAT II Operating Minimums: DH 100/RVR 300 meters.
The DH must be based on the use of either the inner marker or radio (radar) altimetry. Usually the CAT II DH is based on the use of radio (radar) altimetry.
Barometric altimetry is not an acceptable means of establishing the DH for CAT II operations using the standard CAT II minimums (DH 100).
(b) Higher Than Standard CAT II Operating Minimums: DH 150/RVR 500 meters.
These minimums are applied as interim minimums (restricted to higher than standard CAT II minimums) for the first 6 months of operation. The first 6 months are used to validate the effectiveness of the operator's maintenance program to support use of the standard CAT II minimums.
These minimums are also applied when:
i) There are transmissometer limitations (only one RVR reporting system installed).
ii) Obstacle clearance requirements for final approach surface.
iii) Prethreshold terrain limitations (radio altimeter not authorized) which preclude the use of standard CAT II minimums.
iV) Limitations in the touchdown and the missed approach area.
DH 150 and RVR 500 meters are also the lowest minimums which can be approved when the DH is based on barometric altimetry.
Validation of CAT II Maintenance Program.
The airborne system reliability required for the conduct of CAT II operations is achieved by special design requirements and special maintenance programs. When an operator requests authorization to conduct operations with aircraft equipped with standard CAT II equipment, and that aircraft is new to CAT II operations with the operator, all CAT II operations with those aircraft shall be initially restricted (for at least 6 months) to higher than standard operating minimums (DH 150 and RVR 500 meters). This restriction must remain in place until the operator has successfully validated its maintenance program.
If an operator does not have at least 6 months of satisfactory experience in conducting CAT II operations with a particular aircraft type, that operator shall be restricted to higher than standard CAT II operating minimums until it completes a 6 month demonstration program.
e.g. Dammam (OEDF) CAT II Minima
The two different minimums (DH 100 ft and DH 150 ft) are charted according to the AIP Saudi Arabia. The CAT II-minimums for these airfields are charted according to Jeppesen's charting conventions for TERPS procedures, which were used for procedure design by Saudi Arabia, and are covered within Jeppesen's ECOMS - Explanation of common airport operating minimum specifications - concept. Jeppesen charting standards based on ECOMS provide to show both values if AIP provided.
Within more recent minima concepts (such as EU-OPS) Jeppesen only charts the lowest CAT II minimum, as operators usually get certified down to the lowest minimum available for CAT II. Therefore this information (if available per AIP) would not be shown.