Ground Lesson 28 (16): ILS approaches

ILS approaches

• ILS categories and minimums
• Category 1
• Basic ILS approach
• Requires only that you are instrument rated and current
  
  
• Category 2/ category 3
• Typically provides lower minimums
• Requires special certification for pilots, aircraft and air/ground equipment
  
  
• ILS components
• Localizer 
• Glideslope
• Approach lights 
• Marker beacon
  
  
• Localizer 
• Provides lateral guidance
• Placed on the departure end of the runway
• More sensitive on the back course
  
  
• The signal represents only one magnetic course to the runway
• Regardless of what course you select, the CDI will indicate the same off course
• This can be compared to GPS navigation and cid indication
• Always set to the approach course for easier guidance
  
  
• You will get reverse sensing if you set and HSI/VOR to the inbound localizer back course
• Always set to the inbound front course
  
  
• Full deflection is 2.5º
• 4x more accurate than a VOR(10º full deflection)
• Also more sensitive CDI
  
  
• Signal is provided up to 4500 feet
  
  
  
  
• Glide slope 
• When you set the LOC frequency you automatically get the glide slope 
• 0.7º full deflection 
• Usually works up to 10 NM and usually a 3º glide slope, but can be different, depends on terrain
  
  
  
  
• Marker beacons
• Used to help you ID a position on the approach 
• Usually only two marker beacon associated with a normal ILS.
• Outer marker (FAF)
• Middle marker - DA
• Inner marker
• Back course marker
  
  
• When you fly over a marker, you will receive a light and sound
  
  
  
  
  
  
  
  
• Compass locator 
• low power NBD transmitter installed together with the OM and MM on some ILS approaches
• Inoperative components
• The lowest landing minimums are authorized only when all components are operational
• When on component is inop. You must increase altitude and/or visibility 
• More than one component is inop. Apply the greatest increase required by any single inop component
• When glide slope becomes inop. Use LOC minimums 
• Inop. component table in TPP’s
  
• Flying the ILS
• ID the ILS/LOC frequency
• Intercept the localizer 
• Maintain localizer and glideslope centered
  
• Straight-in (NoPT) ILS approach
  
• ILS approach with course reversal
• Fly procedure turn/hold, then intercept the LOC
  
• ILS/DME approach
  
• Radar vectors to ILS final approach course
• ATC will vector you to the FAF
  
• ILS approaches to parallel runways
• Simultaneous converging instrument approach
• Localizer approach
• LDA - localizer type directional AID
• More precise than SDF
• If not aligned with the runway, may still provide straight in if less than 30º off
• Limited approaches have glide slope
  
• SDF - simplified directional facility 
• Localizer type, may be wider(16 or 12 degrees) - less precise 
• May or may not be aligned with runway 
• No glide slope
  
• Localizer back course approach .