Simplified directional facility

Simplified directional facility (SDF) was a localizer-based instrument non-precision approach to an airport, which provided final approach course similar to instrument landing system (ILS) and localizer type directional aid (LDA) approaches, although not as precise.

The SDF signal was fixed at either 6 or 12 degrees, as necessary to provide maximum flyability and optimum course quality.[1] Unlike an ILS, an SDF did not provide vertical guidance in the form of a glideslope.[1] The SDF course may or may not be aligned with the runway because its antenna may be offset from the runway centerline. Usable off-course indications are limited to 35 degrees either side of the course centerline.[1]

Current SDF approaches in the United States

As of November, 2025, the last SDR approach at KMOR was permanently decommissioned. [2][3]

See also

References

  1. ^ a b c AIM 1-1-10 (March 7, 2013 Revision), accessed 2013-07-06
  2. ^ "digital – Terminal Procedures Publication (d-TPP)/Airport Diagrams". FAA. Retrieved 2024-11-13.
  3. ^ "Instrument Flight Procedures Information Gateway". FAA. Retrieved 2017-06-23.


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