BY ORDER OF THE SECRETARY OF THE AIR FORCE AIR FORCE ...

AFMAN 11-217V1 3 JANUARY 2005 305
centerline. It is important to realize that MLS approaches can have final
approach courses that are not parallel to the runway centerline. Review the
approach plate carefully for notes to that effect and for the arrow leading up to
the aerodrome sketch to determine where to look for the runway at the missed
approach point.
14.2.2.2.2.2.1. WARNING: If you are flying a non-computed MLS
approach, and you select the “COMPUTED” approach mode on your
MLS equipment, the published approach is no longer valid and the actual
approach flown will no longer guarantee obstacle clearance. The only time
the “COMPUTED” mode should be selected is when the approach to be
flown is a computed approach as indicated on the approach plate.
14.2.2.2.2.3. Computed (COMP). A computed MLS approach steers your
aircraft to the runway along a course aligned with the extended runway
centerline regardless of the location of the ground transmitters. Aircraft
having MLS receivers capable of using computed approach guidance can only
fly computed approaches. Using slant-range DME and elevation, the MLS
receiver computes the along-track-distance which is used with the azimuth
transmitter’s known location and offset distance from the runway centerline to
compute an offset approach path which will steer the aircraft to the runway
along the extended runway centerline. Computed approaches should be flown
using the AUTO and COMP settings of your MLS equipment.
14.2.2.2.2.3.1. WARNING: In order to fly a computed MLS approach, all
system components (AZ, EL, and DME) must be operational. Failure of
any component will result in aircraft receiver course and glide slope
off/warning flags and loss of course information.
14.2.2.2.2.3.2. WARNING: If you are flying a computed MLS approach,
and you select the “NON-COMPUTED” approach mode on your MLS
equipment, the published approach is no longer valid and the actual
approach flown will no longer guarantee obstacle clearance.
“COMPUTED” mode should be selected when the approach to be flown is
a computed approach as indicated in the plan view on the approach plate.