instrument landing system
هواپیما جهت نشستن بایستی دو حالت را رعایت نماید ، 1- در وسط باند باشد ، 2- شیب مناسب داشته باشد.
هر دوی این ها با سیستم ILS در دسترس خواهد بود.
به عبارت دیگر Glide Slope و LOclaizer
منبع عکس
سازمان FAA تجهیزات فرود را مطابق موارد زیر دسته بندی می نماید :
The FAA categorizes the components this way:
- Guidance information: the localizer and glide slope.
- Range information: the outer marker (OM) and the middle marker (MM) beacons.
- Visual information: approach lights, touchdown and centerline lights, runway lights.
تصویر زیر نشانگر مربوط به ILS را نشان می دهد:
با توجه به آنچه در این مرجع ذکر شده تفاوت نشانگر vor و Localiser به شرح زیر می باشد:
- The localizer consists of only a single course.
- The localizer course needle is four times as sensitive as a VOR needle. Heading adjustments must be much smaller because of the increased sensitivity of the indicator. For VOR work, each dot under the needle represents 2° deviation from course while for the localizer each dot under the needle represents 0.5° deviation from course.
- Because the localizer provides information for only one radial, the runway heading, the Nav. receiver automatically cuts out the OBS, the Omni Bearing Selector knob. Rotating the OBS still rotates the course ring on the instrument, but has no affect on the needle.
Marker beacons are used to alert the pilot that an action (e.g., altitude check) is needed. This information is presented to the pilot by audio and visual cues. The ILS may contain three marker beacons: inner, middle and outer. The inner marker is used only for Category II operations. The marker beacons are located at specified intervals along the ILS approach and are identified by discrete audio and visual characteristics (see the table below). All marker beacons operate on a frequency of 75 MHz.
