Instrument Landing System – (ILS)
What is an Instrument landing system and what does it do? It is there to assist pilots with landing an aircraft safely in poor weather. This is where the runway is not visible from the air although it needs to be visible for the actual touchdown. It may be fog or clouds obscuring the runway so the ILS or Instrument Landing System guides the pilot down to the runway. There are several levels that are graded into difficulty and pilots are rated to land in these conditions. Modern aircraft can do full landings on their own so if you have flown a bit then you may have experienced one without knowing.
The ILS system uses as vertical and horizontal beam which the instrument in the aircraft can read and knows its location relevant to the central intersection where the ideal flight path is located.
Take the Challenge of flying Instrument Landing System Approaches!
Understanding the
Instrument Landing System Display
The next diagram shows an ILS instrument and the indicating needles being high and to the left of center. The small circles forming the cross are the aircraft and the needles show the vertical and horizontal center of the ILS beam we wish to fly down.
In this situation we are low and to the right of the glide slope. To correct this we need to turn to the left a little till the correction has been achieved. To intercept the center vertical needle till it comes to the center. You could climb to meet the horizontal needle but generally holding your current altitude till you catch the needle is the best.
I understand airline pilots always catch it from under not five to catch it. This makes good safety sense to me. Again hold height till the top needle comes down to meet the center of the instrument.
The ILS needles are often also incorporated into you HSI or Horizontal Situation Instrument. So you can find it in a number of places. Older aircraft have it separate in its own display.
Where to find the information to fly an
Instrument Approach.
The big question is what I need to do to use an Instrument Landing System. You need the approach plate or information as you see in the next diagram. This will give you ILS frequencies for each runway, the height above sea level for the runway as well as the magnetic heading of the runway,
It’s worth remembering a runway that is R23 which should be 230 degrees does change over time as the earth’s magnetic field changes. So, the real magnetic runway heading could be 215 Degrees, so this is important to set on your heading indicator and your ILS instrument either the radio display or the HSI (horizontal situation display).
How to Set Up an ILS Landing.
- Look at the approach plate and find the ILS frequency for the runway you wish to land at.
- Program frequency into Nav 1 and set it as active.
- Set the Navigation radio display or heading on your HSI to the magnetic heading of the runway.
- Fly to intercept the runway heading. The general guidance from air traffic control would have you intercept the extended center line of the runway at about 30 degrees so as not to need a major turn while intercepting the runway heading.
Skyvector.com is one of the may online locvations you can plan and get airport information online. Very useful for planning your flights and uploading the flight plan to both real world authorities as I understand it and your X Plane 11/12 FMS/GPS. You can find all your airport information and even flight plan your flight here if your looking for an easy place to get all your info.
ILS Approach in X PLANE 11.
Flying an ILS approach in X Plane 11 or other sims isn’t to hard so lets look at whats required.
1. Ensure your in NAV and not GPS. Select this by clicking on the window (Blue).
2. Use the knob to rotate the heading in the radio VOR indicator to the magnetic heading of the runway. It is 220 degrees even though its R23.
3.Using the Yellow dial select the frequency for the ILS or VOR (Yellow). Then ensure it is the top frequency in the Red small box.
4. If its in the standby ie bottom position push the button next to it to cycle it up to the top active position.
Flying the Instrument Landing System “T” Scan.
Now your ready with radios setup you have to monitor your flight instruments carefully. Remember it wont be a clear day like the pictures, it will be a sea of white cloud most likely. You need to fly the T which is depicted on this cockpit. Focusing on the artificial horizon (top red) you scan to the left to check your speed then back to the center, then to the right and check altitude then heading as well as your decent rate VSI. (Not being a real world instructor if you looking for guidance please contact your QFI/CFI)
Watch your Speed and Direction.
It’s so important to monitor every aspect of your decent so keeping wings level, correct speed and decent rate. It’s about 500 ft per minute once your centred on the ILS beam. Keeping the centre line will be easy initially but it becomes much more sensitive once you’re getting close to the runway. Your decision height will be something like 200 Ft so ensuing your altitude with your correct air pressure setting on the altimeter is the difference between life and death.
Make a Safe Landing.
The final phase you should be visual and this is the picture you want to see out of the cockpit. Two red and Two White lights means your on glide slope. If its more white than red your high as well as more red than white your getting to low.
You should fly the last part visually and make a safe smooth landing as always.
I hope this short guide has helped you understand the basics of an ILS approach, setting it up, as well as flying it safely. It will take you practice so start in a cessna 172 or similar before jumping into your 747 etc. You need time even in the sim when the chips are down, the wind is up and the clouds are everywhere.
Good luck captains.
Gunnie
Instrument Landing System
Not sure how it all works then watch this video which will show you everything in action.
LetsFlyVFR YouTube Channel
Author.
Brendon McAliece is a multi lingual-expat who brings over three decades of flight simulator/PC building experience as well as over two decades of real world jet fighter experience as a weapons/egress technician. He holds a sport pilot certificate giving him real world flying experience. Hi travels have taken him from Europe to the Middle East, Asia and his home of Australia. He has a passion for travel, languages, Flight simulation as well as Guitaring and Coffee. You can read more in his blogs below.
Learn more @
DreamingGuitar.com – DreamingCoffee.com – LetsFlyVFR.com
As an Amazon affiliate I may earn on qualifying sales.