Class - SDF
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<<feature>> Simplified Directional Facility (SDF) provides a final approach course similar to that of the ILS localizer although is not as precise as Localizer. It does not provide glide slope information.
The SDF transmits signals within the range of 108.10 to 111.95 MHz.
The approach techniques and procedures used in an SDF instrument approach are essentially the same as those employed in executing a standard localizer approach except the SDF course may not be aligned with the runway and the course may be wider, resulting in less precision.
Usable off-course indications are limited to 35 degrees either side of the course centreline. Instrument indications received beyond 35 degrees should be disregarded.
This angle is generally not more than 3 degrees.
The SDF signal is fixed at either 6 degrees or 12 degrees as necessary to provide maximum flyability and optimum course quality.
Inheritance
This is a specialization of the NavaidEquipment class and it inherits all attributes and associations of that class.
List of attributes
| Name | Data Type | Definition | ||
|---|---|---|---|---|
| frequency | ValFrequencyType | The frequency of the localizer. | ||
| magneticBearing | ValBearingType | The measured angle between the localizer beam and Magnetic North at the localizer antenna. | ||
| trueBearing | ValBearingType | The measured angle between the localizer beam and True North at the localizer antenna. Note : The True North is the north point at which the meridian lines meet. | ||
| designator | CodeNavaidDesignatorType | The identifying code given to the navaid. | Inherited from NavaidEquipment | |
| name | TextNameType | The long name given to the navaid equipment. | Inherited from NavaidEquipment | |
| emissionClass | CodeRadioEmissionType | A code indicating the type of emission, as defined at the 1979 ITU World Administrative Radio Conference. | Inherited from NavaidEquipment | |
| mobile | CodeYesNoType | Indicates if the navaid equipment is mobile. | Inherited from NavaidEquipment | |
| magneticVariation | ValMagneticVariationType | The measured angle between Magnetic North and True North at the VOR and at the time reported in dateMagneticVariation. By convention, the measure is expressed as a positive number if Magnetic North is to the east of True North and negative if Magnetic North is to the west of True North. Therefore, magnetic bearing + magnetic variation = true bearing. The following rule of thumb applies: ""variation east-magnetic least, variation west-magnetic best"". | Inherited from NavaidEquipment | |
| magneticVariationAccuracy | ValAngleType | The accuracy of the measured angle between Magnetic North and True North at the VOR and at the time reported in dateMagneticVariation | Inherited from NavaidEquipment | |
| dateMagneticVariation | DateYearType | The year the magnetic variation was measured. | Inherited from NavaidEquipment | |
| flightChecked | CodeYesNoType | Indicates if the navaid equipment has been flight checked. | Inherited from NavaidEquipment |
