[rhn_mk1]

I hate articles introducing three-letter-mysteries and leaving the readers in confusion. To add insult to injury, none of the comments seem to acknowledge that the topic is impentrable.

What is the mysterious ILS that was hit?

Even after reading the Wikipedia article, I only have a vague idea - seems to be a radar system, both on ground and in the air. Did the plane hit a radar tower?

[danaliv]

Others have noted that ILS stands for Instrument Landing System. It’s a system used for landing airplanes when you can’t see the runway, typically getting you down to 200 feet, but with special training and equipment you can get down to 100 or even zero (autoland). ILS is the world standard for getting airplanes onto runways in bad weather.

The ground portion of an ILS consists of two antenna arrays, one at the end of the runway called the localizer, and one just off to the side called the glideslope. These arrays produce two fan-shaped signals that vary left-to-right and up-and-down in such a way that an aircraft can determine its location relative to the runway with remarkable precision. The localizer signal provides lateral guidance to the runway centerline, while the glideslope provides vertical guidance down to the touchdown zone, usually on a 3° glidepath. One or both of these arrays is what this airplane ran into.

The system is passive, in that the signals are simply broadcast from the ground continuously, aren’t unique to a particular aircraft, and there is no return or response from aircraft. The ground antennas simply “shout into the void” as it were, and aircraft receivers determine their location based purely on the shape of the signals at the aircraft’s location in space.

For illustration here is a localizer antenna (though note that the airplane in this picture is “backwards,” i.e. the localizer for a given runway is at the far end of the runway, though it is possible to “fly the backcourse” and land with one at the near end): https://image.slidesharecdn.com/instrumentlandingsystemils-1...

And here is a glideslope antenna: https://i.pinimg.com/originals/8f/56/b3/8f56b3b52fb9b81c84f7...

[avip]

Another one of these comments that make this forum always a joy to read. Thanks for the detailed walkthrough.

[JshWright]

There are lots of great YouTube videos explaining how these work with some visualizations.

Here's a good one: https://youtu.be/FeELh0kMSIA

[bbulkow]

Thanks for that, I was wondering if the grounds portion of the ils was hit, or the plane component.

[geezerjay]

Superb comment. Thank you for taking the time to post it.

[AdrianB1]

The article is very clear for pilots and people with knowledge in aircraft industry, it is meant for them. ILS, ADS-B, stuff that is basic domain knowledge. There are strange things in the article, like how a plane with severe damage was allowed to raise to 36,000 where catastrophic decompression is possible (like https://en.wikipedia.org/wiki/Japan_Airlines_Flight_123), but the basic information is there and clear.

[briancollins]

ILS stands for instrument landing system. It's a set of antennae that produce radio signals to guide the aircraft to the runway. The plane must have struck one of those antennae.

[close04]

I think that the audience most interested in such stories especially from this source is familiar with the terminology so they don't waste time detailing it.

How many articles posted here on HN tell you what a CPU is? Or a pointer? Or a container? And that's just to pick a few common terms. News about a certain topic will build on the assumption that the basic concepts related to it are already known to the reader.

[rhn_mk1]

You raise a good point, but in the end the situation is not similar.

The situation in the article can be very well explained in layman's terms. Most people know enough of the ground-world and air-world to understand how things hit and what's important about hits.

However, the article uses an overly specific term, and on top of that, it overloads it with a meaning which is not the one found in literature. Notice that Wikipedia's diagram of "ILS" shows it as an airport-sized system made of several components, none of which is called "ILS".

https://en.wikipedia.org/wiki/File:ILS_diagramsimplified.png

This doesn't make understanding possible, unless you know what "ILS" means in the lingo.

In IT terms, this is akin to saying "A sysadmin tripped over a CISC and fell". To someone familiar to the terms, this translates to "someone tripped over a silicon chip with a CPU, most likely an Intel".

Meanwhile, a layman would look up "CISC" on Wikipedia and be confused about whether someone trippped over a computer box, an instruction set, or a processor. All of this is confusing and irrelevant to the point, which can be understood by anyone: someone tripped over a few cm wide piece of silicon.

Back to the aviation article: "A plane hit a few meter high tower housing an ILS antenna." conveys all the information, but doesn't leave anyone in the cold.

I stand by my initial complaint: any speech that obscures the actual topic behind lingo available only to a small group of people should stay in that small group or improve.

[close04]

> I stand by my initial complaint: any speech that obscures the actual topic behind lingo available only to a small group of people should stay in that small group or improve.

These days, with the internet at everyone's fingertips, I find it very hard to understand the "I couldn't find what it means" explanation when a simple search for ILS returns some pretty clear explanations on Wikipedia or Quora on the very first results page. No need to even click a link. And if you do click you get pictures, explanations, everything you could want including how they can be hit [0]:

>> A localiser antenna. Point of interest: In case of an aircraft over-running the runway, it is the localiser antenna which gets smashed!

And keep in mind that FlightRadar24 is not a site for the laymen. It's for people with an explicit interest in aviation and there's a definite assumption that you understand these concepts. Perhaps other sources were clearer. Just like it's assumed you know what ADS-B, kts, or FL(350/360) are. They aim for a different audience.

[0] https://www.quora.com/How-does-the-ILS-Instrument-Landing-Sy...

[jpindar]

That's an aviation website. Would you expect HN posts to explain all computer related terms?

[egeozcan]

I think it depends on the audience and in this case the site is flightradar24.com. I also had to google that BTW.

[YetAnotherNick]

As other response mentioned what it is, look at this image for get an idea how it looks: https://www.airteamimages.com/---__-_94189_large.html. It is present on the entry side of most runway.

[raverbashing]

ELI5: ILS tells the plane how high/low, left/right it is in relation to the runway when landing in foggy conditions