Palladium From Indonesia, joined Apr 2005, 270 posts, RR: 0 Posted (6 years 10 months 4 weeks 1 day 11 hours ago) and read 9116 times:
Can someone here explain to me how does an ILS work ?
I know it's a device that can guide a plane down safely during bad weather and etc...
does every airport in the world have this device? or only major airport?
I was flying from Surabaya to Taipei with EVA Air A330-200 3 months ago. prior to arrival, the weather in Taipei was soo bad, I was sitting on the window seat and I couldn't even see the ground at all.... it scared me a bit, and suddenly.... bam....the plane somehow landed safely and smoothly on the runway...I was thinking how amazing this ILS device is.
Kaddyuk From Wallis and Futuna, joined Nov 2001, 4125 posts, RR: 33 Reply 1, posted (6 years 10 months 4 weeks 1 day 11 hours ago) and read 9109 times:
There are three aspects to an ILS system...
1) The localiser - This gives information to the aircraft telling it where the center line of the runway is (basically left or right of it.)
2) The Glide Slope - This gives information to the aircraft telling it where the touchdown point is on the runway. This gives the aircraft the correct descent profile. it depends exactly on the ILS system but on average most glide slopes are a 3 degree down attitude.
3) DME - Distance Measuring Equipment gives information to the aircraft regarding distance away from the runway touchdown zone.
Using these three aspects, the aircraft can...
a) find itself on a heading which is the same as the runway center line.
b) know how far they have to travel untill they are over the touch down area
c) Know at which angle they need to descend to arrive at the touch down area and be in a suitable position to land
The localiser transmitter (Projects the localiser signal) is located at the opposite end of the runway to allow the aircraft to be guided along the whole length of the runway. The glide path transmitter is placed at the end of the runway that the aircraft is landing on. the DME can be either outer markers and middle markers or can be a DME beacon inside the glide path transmitter.
It looks like a complex method of landing on a runway, but can be so accurate to guide three hundred tonnes of metal, down a line just 15 meters in width from a height of 2500ft and a distance of 8 miles onto a touch down area and straight down the middle of the runway... BLIND!!
Hope that helps
Whoever said "laughter is the best medicine" never had Gonorrhea
CosmicCruiser From United States of America, joined Feb 2005, 2045 posts, RR: 18 Reply 2, posted (6 years 10 months 4 weeks 1 day 10 hours ago) and read 9082 times:
Quoting Kaddyuk (Reply 1): The glide path transmitter is placed at the end of the runway that the aircraft is landing on. the DME can be either outer markers and middle markers or can be a DME beacon inside the glide path transmitter.
The glideslope antenna is not at the end but about 1500' from the app. end of the runway.
Distance Measuring Equip. (DME) is transmitted on the loc. not the glideslope and it measures dist from the loc. antenna not the touchdown zone.
Outer and middle markers are not DME though they represent a given dist which is depicited on the app. plate.
Kaddyuk From Wallis and Futuna, joined Nov 2001, 4125 posts, RR: 33 Reply 3, posted (6 years 10 months 4 weeks 1 day 10 hours ago) and read 9071 times:
I know that outer and middle markers aren't DME i think i remember 3000ft for an inner marker and 3.9 nm for an outer marker, but i bet that changes from airfield to airfield.
I also didnt mean that the DME was transmitted WITH the glide slope, i just guessed that it might be in the same BOX as the g/s transmitter. Clearly it isnt, thank you for clarification
Whoever said "laughter is the best medicine" never had Gonorrhea
Timz From United States of America, joined Sep 1999, 6231 posts, RR: 8 Reply 5, posted (6 years 10 months 4 weeks 1 day 8 hours ago) and read 9039 times:
" it measures dist from the loc. antenna not the touchdown zone."
So in the cockpit, the DME reads 2 nm when they're over the threshold?
CosmicCruiser From United States of America, joined Feb 2005, 2045 posts, RR: 18 Reply 6, posted (6 years 10 months 4 weeks 1 day 6 hours ago) and read 9011 times:
Quoting Timz (Reply 5): So in the cockpit, the DME reads 2 nm when they're over the threshold?
Yes, if you want an example see EWR ILS 4L. The LOC has DME and the FAF is HOWYA (7.5 dme) and the Missed Approach Point (MAP) is the threshold of 4L (displaced thsld) at 1.5 dme. The ldg dist. beyond the threshold is 8460'.
The upper portion of the chart has various information - frequencies, notes, remarks, etc.
The middle section is a view from above of the approach, showing the courses to be flown, including the localizer (arrow with right side shaded).
The bottom portion has a side view of the approach, showing what altitudes you'll be at throughout it, including the glideslope (grey shaded arrow). Next to that is an airport diagram. Below those we have the weather minimums and other information.
If you want a more detail explaination of anything on the chart, just ask.
Pilawt From United States of America, joined Dec 2003, 100 posts, RR: 0 Reply 8, posted (6 years 10 months 4 weeks 1 day 2 hours ago) and read 8998 times:
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From Indonesia, joined Apr 2005, 270 posts, 
From Wallis and Futuna, joined Nov 2001, 4125 posts, 
From United States of America, joined Feb 2005, 2045 posts, 
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