ILS
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ILS Instrument Landing System. How an airline pilot uses an ILS, a technical description and ILS limitations.
Accident - Korean Air Flight 801 in Guam.
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Transcripts are approximate. Email us if you have any questions.
00:02
Adam. Sam. ILS. Instrument landing system, ILS. Do you like ILS approaches, who doesn't? Why do you like them? They’re low workload. So easy. Is it because we've done say many, or is it just so well designed probably a bit of both. But it's just too easy. One thing that fascinates me, which I'm sure to talk about is how long they've been around.
00:29
Oh yeah. How long well since like the second world war? No way. Yeah. And they're still liked. Kind of standard. It's still like the most common. They're still better than a anything GPS. Yeah, they did. So simple, really, but so clever. And Works really well like, say considering a industry where you would think technology in Adaptation with technology is right at the forefront.
00:55
Actually, we're still using a system from 70 years ago to land. Yeah, I understand. It's a very elegant and sophisticated implementation of analogue, radio engineering. Hmm. So it's old, yeah, it's really old. I'm either question which I had previous prepared for you. Whether you like the or not so you've obviously we do a lot of them.
01:16
Probably what 90% 95% of approaches. At the moment. Yeah, my next question was in 12 years of flying. Have you ever been let down by one? Have you ever had any like Failures or troubles with them. Hey. It's the pretty reliable as well considering this so old it kind of like the system works.
01:36
That's what impresses me the most about. It really is like Just such a simple, beautiful system, that's been around for so long that works. That doesn't really. Fail. It's just easy. Every passenger out there, the likelihood is that you're going to be using this system whenever you're sound on an aircraft.
01:56
So, it's talk about ILS. I think we also have to talk about how to land a plane. Yeah. Okay. Because 9 out of 10 times, this is what you'll be doing. You said Do you like them? Well, what's the alternative? Well, the alternative I suppose, the alternatives are some sort of RNAV GPS approach.
02:15
Or a more traditional non-precision approach, like a VOR approach or an NDB approach. Yeah. And then I suppose the only other rare options are like visual approaches or circling approaches. It's been around since the second world war, but this is the only precision approach. Yeah, that exists. Pretty much, yeah.
02:35
Everything else we call a non-precision approach. Yeah. And comes with a little bit of a headache, quite a high percentage of accidents. Come from non-precision approaches. Don't they by their nature? They're just slightly more complicated. Slightly less Reliable. Yeah, the chance of having lessed off often thinking action or can specifically controlled fly into train on a non-precision approach.
02:56
He's like 10 times higher than a precision approach and then if you move to a circle and approach for a visual approach is higher and higher still. Yeah, you save it, option is a precision approach. Which is basically an ILS. But if we go back to absolutely basics, you're in your aircraft somehow you've got airborne and you've got a land.
03:13
So you need to line up with the centre line. Descend at the right angle. And you need to slow down. Visually. You can do all of those things You could find the airport. Could find some geographical features line up with the runway. You be able to see the terrain, you'd be able to choose when to configure and so on with the ILS allows to do is do it all instrumental, logical conditions without seeing the runway at all.
Description
03:42
And it is magic. We've talked to separately about low visibility operations, but Typically on an ILS, you'd be you could get down to 200 feet above the runway. New basically almost at the end of the room. Where that point, yeah, that's how it feels. And but when you see the runway come out of the, the clouds and the fog, or that moment is pretty special to have lined up like that.
04:06
But if we didn't have any Radio navigation systems and we're doing it all visually. Most airports have a PAPI or a VASI system where they send out. White light and red lights. You're following the right descent angle towards the runway. You'll see two reds and two whites, And if you're a bit too high, you'll see three white or even four ways.
04:29
If you're too low, you'll see more reds. But there's PAPIs always thinking. They're like a visual. Version of the ILS. If you like what the radio navigation is allowed allows us to do is hunt for the runway. Using sensors that we don't as humans have because we can't see anything because this IMC The radio nav is like listening.
04:52
For. The runway. Yeah, and if it hears a bit too much of one tone, it's too far left. If it, if it hits here's a bit, too much of the other, it's too far, right? So it's kind of light when you get up in the night and your bedroom, He need a piss.
05:07
I see that's not the right example. I was trying to think of an example where You're in the dark or you're blindfold and you can hear what you need and you move towards the sound. Yeah, that's what the aircrafts doing. Yeah, it's here in the Tones of the glide slope and the localizer.
05:23
And it's like hunting, its way in towards as it narrows intowards the runway, right? Yeah. Yeah. It's really old and very analogue system. It's kind of genius. I was genius. So delivers the aeroplanes. As you said, 200 feet or the original Know, ideas delivers, the aeroplanes 200 feet and then you then will pick up the the lighting of the runway or the PAPIs and carry out the landing visually from there.
05:47
I mean, it's incredible, really. It's like on Star Wars. Which came after the ILS. Then yeah. So long. Okay. And they have on our sci-fi, they have those like tractor beam, which is where they kind of like lock onto the spacecraft and just pull it into the spaceship.
06:04
Yeah, it's basically what the ILS does. Yeah. You're in like a beam vertically. And horizontally. And you're being pulled in effectively, with the use of the aircraft systems, like the autopilot, for example. Yeah. Towards one dot like it, where you're going to touch down, In the touchdown zone. And then, Later, iterations of the ILS at later categories.
06:27
Later versions have reduced. It even further. We talked a little bit about this in low vis. Reduce miinimum altitudes even further. Now, to the point where some FLG don't even need to be able to see anything. They'll just literally land their aeroplane. I mean that's a facility there aircraft as well.
06:45
But, but it's the same ILS. It's the same ILS. Guiding, Guiding the aircraft all the way down to to landing all the way down to search. Now, I think the radio aspect of the ILS, has been updated over the years for the fundamentals of it. Exactly the same. If you ever seen the glide slope antenna, No, not I I've seen it but it it doesn't stand out yet.
07:08
It's about 1000 feet from the threshold, okay? And it's to the side of the runway, okay? And it's hard to spot but that's Projects. Three degrees. Thereby at The threshold, you'll be 50 feet. If okay, I see but the localizer antenna. Everybody can see that. He's plenty of accidents, where the localised antenna have ended up in the aircraft.
07:29
Yeah, or hooked under the tail or something because they're just station, just off the end of the runway on the extended centreline. You know, the far end at the runway. So the runway your landing on, it's the directional antenna of which there's quite a lot of them. They're at the far end for the runway that you're landing on.
07:45
Yep. And there. Angled. My understanding is their angled exactly. Right. So that at the threshold of the landing runway the beam is 700 feet wide, okay? So the beam depending on the length of the runway that the ILS is on the angle of the localizer beam is is wider, okay or shorter depending on the length of the wrong way?
08:05
Okay, interesting. So, we've established this kind of very simple system, which has a localised and a glidepath guide to sin. Vertically. And Horizontally. It's been around this second world war. Later, versions of also been coupled with some sort of distance measuring as well, so you can actually This addition measuring equipment or more fashioned that was like marker beacons.
08:31
Yeah. When you look at ILS theory, there's loads of stuff about marker beacons but people should probably know that. Last time, I thought about my yeah, was when I played flight sim in my bedroom wasn't finished. Exactly commercially. Now, most most ports have a DME Associated with the ILS, which is essentially, yes, add some A lateral distance from the thresholds and at the technical talk about complacency Because we do these ILSes so much, but the times when I have flown, ILS, is that don't have a DME.
09:01
Yes, not tell them on the approach that I'm like, hold on, there's no DME is my monitoring is say poor and I expect it co-located DME. Yeah. So some airports you could use a DME on the airfield, it might be on a VOR or something but most ILS is have IDME with paired with the frequency as well.
09:19
So that gives to the point one of a mile distance readouts all the way down to the threshold. These old markers beacons, you probably would have one or two like an outer marker and inner marker and do you remember on die hard? Yeah. Then they mess with the ILS.
Die Hard
09:35
They turned the ILS off, but because Bruce Willis, He goes, there was fire basically. Like he didn't know how he did it, but he made like an approach lights out of fire, and some oily rag with some oily rags. He was like, at the end of the threshold, like, with his arms and isn't it.
09:49
A British flight crew here? Like, I think, possibly something like I follow in the procedure. Say, perfectly and the terrorists are like laughing like, yeah, and he's knee keeps saying something like Little bit closer, come on or something, the terrorist, and then they smash into the ground, right? Okay.
10:06
And yeah, it's supposed to be The British, they're crashes knit and Bruce Willis is saying like My these like, basically destroy as he watches it smashed into the ground. I'm sure they go over the, they start talking about beacons, right? Then, which would be like the ages with 80s?
Technical Description
10:23
Really nice. Yeah, I think I didn't understand any of this but the outer beacon was Help blue, help your establish to get to the outer beacon. You should be kind of turning on to the localizer, but that it can be a various distance, It doesn't tell you what height to be.
10:38
The middle marker might be whether decisional attitude was, right? And it's Amber. And then the inner is like really close. It's like you're on the threshold sort of. That's why and these markers or more recently, the the DME would help you. Again idea of whether you're on the correct, Glide slope because it would have often have a height check associated with it.
11:01
So, as you go over the market, you should be at Say 2000 feet so you check, yeah. So forget all these markers because they're eggs but basically, I don't know what what role of thumb do you have like 10 miles 3,000 feet or something? Yeah, exactly. Yes. So on a three degree if you good at Pythagoras like on a 3 degree glideslope.
11:20
Yeah. For every mile you know, you know exactly what height you should be. That's really on that channel. 100 feet of a mile, isn't it rough? Yeah. And you should be able to. However there are ILSsers with the are not three degrees. So, just generically talking about landing in aircraft three degree.
11:36
Slope is the Ideal. Vertical descent slope because It keeps you clear of terrain and obstacles as you make your approach. Empties shallow enough for you to slow down in decelerate, on I guess is basically why three is correct? But there's plenty of ILS. Is that aren't three degrees? Yeah.
11:58
Say the guide slope can be adjusted to not be 3 degrees and then the DME helps you realise how far you are from the runway in and how high you should be. But if you're on the glide slope, you have to be at the right height. Yes, unless something's gone terribly wrong.
12:12
Yeah, so yeah. Never mind these these markers and stuff, but the DME with the slant range as well. So it's actually the distance. As you fly down that three degree, Three degree. ILS. And the technical stuff that I think this in the ATPL is that the Localizer is transmitted in VHF.
12:31
But the glide slope is transmitted in UHF. But you never have to tune the glideslape When you tune. The localizer is always paired with divided slave because you don't know the frequency of the glycerative, it's in the 3,000 ultra high frequency range. And as you know, from radio theory.
12:50
The higher the frequency, you get a nice good resolution on the signal, but you get less distance, Right? So your localises usable maybe out to about 25 miles. Yeah. But the glide slave, maybe is only really usable out to 10 miles and we might use it. But with caution, It's outside, it's protected.
13:10
Ranges. And on the char, you'll see usually depicted visually like where the 10 mile glide slope protected area is And then this localizer. And glisely. A frequency modulated and it's done in a way similar to FM radio. Like bro, you know, music FM, public radio, And there's a low above a 90 Hertz on the left of the localizer and 150 on the right.
13:37
And the aircraft like I said here is it automation? Just two tones. And when the amplitude the volume of those two, you know frequencies is is exactly equal. You're on the centerline cellphone. Yeah. I think about the engineering of that because if one of all those localizer antenna if one is Slightly more powerful because it's just not tuned, right?
13:57
Yeah. Then you're not going to be on the central line. Yeah. Say it's really well engineered because they're like, you said, they never go wrong that? Well, that I'm aware of. Why'd you saying that the other day on the approach? I was like, what's it? I'll see doing there.
14:08
I think it's more the aircraft, there's you. Well yeah, exactly see. Yeah, it could well be the aircraft. Although it's like the industry standard still. From my reading. Although I've never been there. I do believe that in the USA. There are a lot more GPS and I have approaches They outnumber ixes now from what I read, but that's mainly due to the fact.
14:29
This so many like little regional airfields and airports. I think you still find ILSes at most of the major airports but that's interesting because the I think it's 100,000 pounds a year roughly per runway to have an ILS. Okay so if you are in some on some little airfield that's a lot of money.
14:48
That's a lot of overhead. Yeah. Amongst all the other things to maintain your airport. So that's like when you fly to these little Greek islands that we we might be more used to you. That don't have an ILS even though there's no Geographical physical obstacles or anything that mean you can't have one.
15:02
It's just a cost. I think that prohibits this But with augmented GPS systems. He could technically. Have accuracy. It would be measured differently but you can have accuracy as accurate as like an auto land system. Yeah. Is potentially possible in the future and all the Capabilities basically, on board the aircraft, the ground.
15:23
Just have to have a little GPS augmented. Like gbass equipped thing. Whereas that the maintenance installation for an IRS must be massive. Yeah, big old powerful transmitters on they but I think it's going that way slowly. I think, eventually ILS’s will be faced out in favour of GPS but until they have the capability of like say being able to auto land and You know, visibility fog, and I guess it under 80cc have higher capacity on ILSs than non-precision approaches.
15:52
Maybe, I don't know. Yeah, possibly. Yeah, is he why? They but I guess so, although That leads me underlight though. One thing was going to say about the another limitation of the ILS is, obviously. It's You know, it's a freak, it's a frequency, it's a signal radar signal being sent out.
16:08
Yeah. And obviously, that can be subject to interference and it always used to make me laugh and you'll know this from flying out of Gatwick as well. If you are on approach behind like an Airbus A380. Oh yeah. Because it's so like so damn big. Basically like blocks the signals for any aircraft following behind it.
16:26
Like blocks the localizer signal, So I forgot about that. Yeah, you remember? So the Emirates just coming in the Emirates A380s coming in it like, was they had trouble with it? Like distorting, the localizer for aircraft behind? So, if you are coming in behind the A380 a traffic would say A380s coming in, can you accept the RNA?
16:44
Have approach, which obviously, it's not subject to the same. It's fairness. That was another. I'm not ahead of that anywhere else. They? No, don't think Emirates were even aware. No, the nuisance they were causing a gateway. He must just be a gateway. That's weird. The Gatwick thing, The frequency range of the ILS is band, is small.
17:01
Anyways, it's only 108. 1.1 to 111.95. If you like around London where you've got a lot of ILS or I don't know. All sorts of places you can, you know, you could quite easily pick up the wrong localizer. Yeah. Because it could share the frequency sticking with that for a second done.
17:19
So like thinking about the limitations in low visits, I think we oh we did talk about this in low vase, There's like a protected area. Because you're solely relying on the localising, the glypath to fully also land. The aeroplane that you've got basically have the aircraft On the ground like back away from the runway so they don't need to feel ground vehicles.
17:38
So they don't interfere with the signal because we'd so dependant on it. Yeah. So someone parks their massive one packs of aircraft in the way here. Yeah, it bends the signal business signal and not ideal for someone doing a low visibility approach. Holy dependant on the On the reliability, the ILS.
17:55
So maybe an ILS is like, the peak of ground-based navigation and we're moving to what they call performance base navigation. Yeah, which is all the capabilities on board. You're using the satellite network. Yeah. Which isn't on board, but everything else is on, but the aircraft is determining its position.
18:12
Not the ground based system. Yeah. NDB's have gone and we don't fly down airways that are It designated by VOR as anymore, but ILS is incredibly useful, reliable system as old as it is. But maybe that was the peak and the end of ground-based A navigation and radio navigation.
18:33
One thing that glidepth can't do is it can glidepath can only be straight in and on the constant path, you can't. There's no sort of adapting it. So, With an on other person thinking of places, like, Nice and others. It's what I call like a bendy on a, it's like a curved aren't have approach, which obviously, the aircraft.
18:53
Using the satellite network is perfectly capable of flying and it will kind of really helps. If you have to rain issues, or But I really says that they tried a variant of the ILS called the instrument guidance system that IGS And that was the first attempt at doing a bendy IL and that was a kitech airport.
19:13
Yeah. As you like, watch YouTube and stuff, just have a look at Kai Tak airport in Hong Kong. I think it's closed now, but yeah, basically, because of the terrain and the topography around there you It kind of had to I think I don't know how it works. Exactly. I think you flew like one ILS like towards the hill and then you picked up another ILS.
19:34
Which turned you on to final approach, but it was like a lot, a very late turn on finals and flew. And ILS, you flew a ILS on a base turn. That's right. Basically then you turned onto the final IS or over. Just visual when you basically flew past this Chinese lady putting a washing out like You know, probably using the jet blast to like dryer clothes dryer sheets.
19:55
Yeah, because the pictures always show that the aircraft and they're always seven fours. Yeah. I like below the height of the buildings that I find three. Yeah, but obviously Hong Kong is A good example of there's nowhere, really that good to put an airport, let alone a beam that stretches out 10 miles, it doesn't have train in the way.
20:13
So they obviously built the new airport in Hong Kong where they made an island out of. Yeah. Have nothing. Yeah and I'm sure this some like dead easy straightforward ILSs, then now. Yeah. But they tried an IGS there. Did they try this thing? Called an IGS? It didn't really delve too much into it, but it was like a variant of the ILS.
20:31
I wish was what they were trying to attempt to do, but there's been other. Try, people try to sort of tinker with the ILS. They try to microwave landing system, the MLS. Yeah. Wait, was, I think to try and reduce separation but that has been a garden and not really work.
20:44
The ILS is just kind of like the stall wart of precision approaches. It's just Just don't mess of that. Like it works. Yeah, slight limitations but it works you know And the To the way that it works for the pilot is the standard of performing in approach which is you one lateral and vertical guidance and you want it's like we said about TCAS is so simple.
21:08
Fly towards the dot you know or fly towards the line. Yeah, pretty straightforward. It's like a very simple boring computer game in a way. Yeah. So now we're moving into like the precision like approaches where they're Their non-precision approaches. Using probably GPS that Maybe it's augmented or not, but The display to the pilot it, they tried to make it look like it's an ILS basically.
Manual Flight
21:32
Yeah. So that's how good. Not only the system was but the The best system seems to be the one where this simple as possible for the pilot. Yeah, definitely. Well, I say, I was gonna ask you like, we have it so easy. Now, we just repress a button and it with the autopilot engaged, when was the last time you try to fly an ILS manually.
21:54
So without like, on our aircraft without the flight directors, and actually just trying to intercept the localising, the glide slope manually, which you watch the first officer day? Yeah. They keep asking me like, can they do? And I'm like, yeah. Okay fine. Yeah. But in the sim. Yeah. And probably not all engines running either.
22:12
Yeah. And it's quite hard. Like I was probably Aces it. Doing my light instrument rating. Well, true story on my some kind of line training not so long ago really I was quite new back to the air bus. Those parallel approaches into Heathrow. And it was about 60 knots, wind it like 3,000 feet.
22:32
And i was joining the localizer. Manual. So raw data ILS was part of the training celibus. And i hadn't. I wasn't using enough bank angle rather than doing the right rate of turn, Okay? Because I guess I'm so out of practise like I was flying the output. Like I just wanted to get down to the localizer.
22:51
Yeah sure. But there are standards for Instrument turns on there. Yeah, I guess you can't swing over onto that. Yeah, well, I guess mine was too shallow. Right. Okay. Can I set off the alarm in the tower? When the radar? That i would go through and, and it's compromise.
23:08
The other Runway that was genetic parallel approach, right? Thanksgiving action. I really yeah, it was all your fault. Yeah, it was. I suppose that time. No only because I was new and maxed out but I was just so used to. I'm not having to worry about like rate, one turns or do you know what I mean?
23:29
If you flying raw data, Stuff. You need to leapfrog from like one instrument procedure to another almost like. So it's reliant on. You know, time in the turn, how many seconds, what rate of what bank angle will you need based on that speed? I mean, that's how people used to have to wear these things out say because they didn't have a DME.
23:47
Yeah, didn't have GPS. So they were flying. Instrument stuff all the time. But now, we kind of get Just a nice little vector on to an ILS. It opens up another like discussion really doesn't it like it's probably a whole podcast on like awesomeration and you know, it's just too easy to use the automatics.
24:04
But to what detriment are we like? Actual manual flying skills. Well, it freeze you up to monitor other stuff And if I the hardest part of any pilots career, is your single pilot. Twin engine. Instrument rating stuff. So flying around in a little twin engine aircraft. A single pilot table manual.
24:27
And it's all. What we're saying these skills that we've lost? It's all. Yeah, instrument rating skills. The yeah, i i'm probably lost. I'm not saying it. It might be able to pick them up again reasonably quickly. But monitoring the automation is important And if you're able to do that, that frees you up to think about other things.
24:48
Yeah. Mean what, you know, when you're thinking about and like a base turn like is a cabin. Ready? How far is the aircraft in front? Yeah. You can think about? Yeah, not a lot of space. Yeah. It's like say you get it's too easy. Yeah. It's too easy. But these these aren't have approached.
25:07
You can't really fly the manually anyway. No, no. So Your interpretation of what the automatic's doing becomes the challenge like wasn't doing now. So I think if it If the aircraft too violently light joins the localizer or if it turns the wrong way you kind of get a sense.
25:21
It's not it's doing something not right there, it's a little bit more unknown at the moment with the onever approaches as how it's interpreting. The database and the line that it's that it wants to fly. Yeah, whereas you know, when it's when it all your pilot is doing is hunting, the ILS signal Say it's a bit more straightforward.
25:40
That's right, summarise what we establish a very reliable sister. Expensive though, but works, even around for 70 years, still working. Well, But yeah, there are ultimately brought down in Diehard tea there. Yeah. The British British Airways thing or whatever that say open tea. Yeah, terrorists. Yeah. Yeah. If you set up in a local church, which is what they did.
26:04
Yeah. And like the interfer with the guy like plugs his computer and yeah, less and changes there. Yeah. The glide slave. I didn't know how much you want to talk about, because it's so day to day. What we're actually. Doing on on the ILS. Like, you know, how we almost like how we land the aircraft.
Typical ILS
26:22
Yeah, I don't know how that links into. It's just such a typical manoeuvre Because that might help talk about the accident. Because, yeah, fair enough where things should be happening and yeah. Okay. So typically let's let's use some UK example, any UK airport. Where final long, let's say another labours it'll generally be radar, vectors onto the approach.
26:42
So air traffic control are going to give you headings and descent towards the island. And where does the approach start technically in my TPL questions. But you got your initial approach fix. Yes, finally approach fix. But it's different from the arrival. Nine times that attend the arrival in the UK just becomes radar vectors.
27:00
To the approach. The approach is basically a big just draw a big line out from the runway. Yeah, and join the localizer and at some point during the glide sleep. So, yeah. However, what we're getting there, we're being sort of radar vectored or positioned towards the to the approach, just kind of spacing.
27:17
And depending, how busy it's traffic, You're trying to think ahead where that control is going to send you And you're trying to look for threats like, The terrain and maybe the weather. Yeah. And you've also, you know, that ultimately you need to arrive at the right height at the right distance but you don't know.
27:37
Where the control is going to put you on that because you don't want to be above the glide slope intercept altitude otherwise is recoverable but that's hard work to capture the gly slope from above that's that's a whole different. Different to say from below, which is like standards. So, imagine you got.
27:56
So, the 10 mile point, let's say that you insert the glide slope, you're supposed to be at 3,000 feet so you're trying to judge With your experience and air traffic control, and whether and everything else. Of making sure the aircraft is down at 3,000 feet. By the time you get to that point but not too early Otherwise that becomes an inefficient noisy.
28:17
Fuel burning. Yeah, annoying people on the ground because you loud. So the game is, can I get from top of descent? To a thousand feet where we want to be stable, which is when the engine's come up, Can I do that? Well, idle power the whole way. Yeah, exactly.
28:32
Yeah. And to do that game, the aircraft control may or may not let you Increase or decrease your speed. And they may or may not give you an idea of how many miles you've got. Yeah. And nobody wants to fly level with the power up because technically then you're annoying the people below but that's the game you play and then everybody knows Pilots have got to be so good at maths so you have to just constantly be any three times table.
28:57
Yeah yeah. She's like really Easy. And i don't i there's a blazer ways to do it, probably the main way I do. So look at a 10 mile final. I'm going to be 3,000 feet. Yeah, I just work backwards from there. Everybody does a differently. Everyone works out differently.
29:12
Don't they? So, when we joining the localizer, maybe just outside that 10 mile point, It will have been given an intercept heading, which will be probably roughly 30 degrees off the inbound and then you're on your own then really. It's then down the radar vectors are over. It's up to you to get on the localizer whether that's going to be manually or you've probably got a different perspective on joining their legalizer because If you do a little bit of radar veteran.
29:36
Yeah, yeah. Because you're a trainer. Yeah. So you have like a radar display and you're you're the one giving the rate of. Yeah. They're just in the same, the displays not grace, and basically, using their Okay, the pilot is now display. Give me a rough idea. But yeah, it does, it does change a perspective because now when flying I'm kind of thinking they should be turning us now because that's normal right to start turning them in the simulator, you know, based on what about wind and stuff, do you go that to that level?
30:05
Yeah, yeah, see have a, yeah, we're going to be have a ball park mileage across track mileage, and which you would turn them onto the localizers and then you just start for when you're on the lake lies. That's great. But if you if you've not If you've turned them on to tie.
30:20
Yeah. They might be above the glide slave Over the glides that disaster. Yeah, not yeah, on the localizer. It's going to the localizer inside 10 miles and they're not yet on the glycelope. So, Technically not approved to decent well, Yeah, not a pretty to descend on the glypath until On the localizer.
30:37
So yeah saying Amsterdam I've had them like trying to get me to join well inside for miles. Yeah. Still descending above the glide slope. Yeah. But normally what, a nice 10 mile. Maybe a mile 10 mile final? Yeah. It's probably joining. So speed wise, you'd be joining the localizer out of 10, 12 miles about 200 knots 200, cowboy 209.
30:59
Okay. And then, so we talked about three degree slope which generally equates to about six, seven, hundred feet a minute, rated descent down the final approach. He really aircraft are generally back at 180 knots at that point and then Whatever. Depending on the airline, where you have to be stable by normally a thousand feet.
31:20
You would then work backwards from there for your final configuration from 180 knots. The landing gear and the rest of you flaps. Achieve. To achieve that by By a thousand feet. So how do we know we're on the right? Glide slope. Hijack. It, we check it against a height against distance measuring equipment.
31:42
To make sure that it's the correct glideslope. Because What has happened? I've never had it, but you could capture a false glide slope. Yeah, I think if it's, if it's somehow reflects off something. Yeah, it can. Multiply yeah i think they're always so the glycerate. Let's assume should be three degrees, the false one will always be multiples of it, 60 degrees 99 yeah you'd be pretty He didn't show on a 9 degree, glad so you'd beating special 2000 feet a minute, every pretty yeah?
32:13
No, I don't think I've had one but if you're capturing from above You could capture the wrong. Glideslope even. Yeah. Yeah. If that happened to be a false glidely and all this systems on board and on the ground I think try and stop those problems happening like false localizer capture.
32:30
And false closely capture and stuff like that. And then another way is eventually the radar will come alive. M at 2500 feet. So that's your chance to check. Well. Am I? On the right. Glide slope based on. Fact, that That's gone off. Seven and a half miles basically. Yeah.
32:50
So, I think that's interesting because I mean even the SOPs are written as if you're going to do an ILS. Yeah and then it's like the other approaches are an exceptions. So everything even in my mind is set up for that the way that the Arrival in the approach goes is like an ILS.
33:06
Yeah. And then you insert other procedures if you're not doing analogue, everything's kind of set up for that Mean. Even the Airbus is kind of designed to go from like parish to Heathrow. Like ILS to ILS. You just press one button and it should basically just do everything. Yeah, yeah.
33:22
That's how every day flying ILS and when I flew and you've had similar experiences like Charter Airlines, you do a lot more non-ILS stuff because you'd be flying a places that don't have that equipment. And if you fly in bigger carriers that fly to more Hubbards spoke stuff.
33:38
You do just tend to have a career full of like ILS not necessarily you'll see a lot more of that more. Yeah and there is a skill Element to that that you might lose some of the other skills. And then there's also the It might, you might just find it slightly more boring but then Going back to the statistical.
33:56
Look at it. They're truly is plenty accident reports that show how an aircraft crashed. Performing a visual approach. And then the last line of the report is a functional. ILS was available. Yeah. Yeah, the lowest chance possible of controlled flight into train should be on an ILS. But it does happen.
34:15
Okay? It absolutely talked about a couple of limitations of their Of their ILS. False glideslope, false localisers. And to be honest, I don't know if you found the same, when it's sort of researching. Accidents and incidents. There's this quite a few out there. Maybe more incidents than accidents, where The limitation of the ILS with false captures and things have caused issues, but a lot of the time it generally gets caught, like you say we're checking like the radio altimeter or something's not right percent rates too high.
Korean Air Flight 801
34:48
Another. Interesting. Thing about the limitation of the ILS, which, yeah. When the ILS is not working, it is working. What it looks like. It's working That's a, that's another potential problem. It was a Korean Air Boeing 747. Which sadly had an accident at Guam in Asia, back in August 1997.
35:14
Basically, the crew were, and obviously, always caveat with talk about accidents, we learn from them and Everyday things better next time. It's not to apportion blame or anything like that. But basically, the crew have been told that. Of the ILS glideslope was an operative. Either than no times or from air traffic control, but they knew that it was an operative and they had discussed this in the briefing, according to the flight to the copy voice recorder However, they were confused.
35:42
They became confused because they're instrument was sharing, like, down the approach that there were actually on the glyes, slopes, so they kind of thought, oh, it's working. Maybe we could, maybe we could use it. And there's no warning flags to say that it was in operative. But basically it transpired that the maintenance staff had left the system in a test mode.
36:03
Which I understand I sent out sends our carry a signal, but no displacement information. So basically, the result is that the Flight director indications show that the aircraft is perfectly on the centre line on the gly slope, no matter where it is. As long it was in a kind of broad arc of the ILS and yeah, so they They were 30 looked, okay, and just kind of followed it.
36:26
And I think there was a sort of a That busy workload. Throughout the descent as well and not not monitoring it properly. Essentially the ended up. Yeah, control flight into terrain. On the approach in IMC conditions. I mean, talking about learning from Mistakes. I mean, you would think that that was that would be a well established phenomena that there could be a radio aid that you spend your career relying on There is.
36:55
Emitting. Perfectly valid but totally erroneous. How many sense? Yeah signal. Yeah, I mean, as surely something you've got to look out for in your career but how many times I mean, I I say I've seen it before both in training gun myself You guys? Oh yeah, I left off.
37:13
Oh look, it's working, you know. Yeah. Oh that's good because we all like ILS llike I've had it flying to, you know, some countries where the standard of the no times is a different. Let's say and you're like so does that mean it's not working? Always working, I've had it on my line, check the other day where it was, no time to runway closed ILS off.
37:34
Well, and then, so we're talking to One. Country asking them. Can you call ahead and find out? What the approach we can expect and they're saying it's one thing in all the way down the descent they're going to notice the ILS and we're saying well it's must be localizer only then and there It any ambiguity at all?
37:52
You need to take it out the flight day. You've got to keep resolving the situation. Yeah. And that was obviously the case here because there was some CVR transcript that showed there was ambiguity about whether the glycolate was working. But before you get to that situation, that has to be a bottom line that you have to be aware.
38:11
And I don't know what point in your training. And when I learnt this, but you've got to be aware that if something is no timed, I'm sure there's other accidents. Like where viawars or something? No time does As unserviceable. You do you? You do not follow them, you do not go.
38:28
Oh, it looks like it's working because clearly that this can happen. Well, this example. Yes. So literally it wasn't working. It was left and test mode. But, I mean, How crazy that test mode, just sends out carry a signal that shows you being like on the or did you know that?
38:44
No, I love any that That was a possibility. No it makes you think of like all the like tens of times that I've heard crews or I said oh look it's working you know in Yeah, I'm gonna say we would have followed it but this temptation is there to follow it and absolutely.
38:59
But like we always say about you've had 10,000 hours following and your instruments believe in your instruments and now you've got a fly, a low close roning approach. With a glide slope indication that you can't turn off. The eyes are just going to be like, oh flyer fly down, fly up.
39:18
So that's a horrible trap that they're in and like everything we always talk about reasons, Swiss cheese model, There's lots of layers here where it could have been trapped but The the trap was set for the crew if you like yeah by saying there's an ILS here's a signal it's on your Wherever the 74 is pfd.
39:37
Equivalent was right in front of you. And look, you're on the glide slope. Yeah. And there was plenty of ways that the action could have been core. And but what horrible trap to set for them, definitely a lot of Navigate for emit on. A test, but they will admit the identity TST as test.
39:55
I've seen that before you, but these guys were expecting to use the localizer part. And how unfortunate that they glide. Slate was radiating at the same time? Yeah. I don't know if I've ever I may have had that I've got memories of this happening in Naples to me, where it's no time to the glide slaves US, and you can't quite get to the bottom of it, over the radio communication with air traffic control, But they briefed a little bit.
40:22
A read the briefing from the captain. I don't know. What the environment generally was like in. Korean air in the seven four and aviation in that day. But the brief briefing seems a bit short one-sided. There's not really any identification of threats and even just listening or reading the transcripts to the brief.
40:40
It's not really clear whether Because he's talking about ILS. But I think he means he's doing a localizer. So he's doing a non precision approach. You need to be pretty clear about what you're doing, what you're doing. Yeah. And then, they end up. Trying to follow the glysely but the flange engineer and the first officer made, plenty of comments about the guys slaves not working.
40:59
Yeah. And the transmission from the tower was Join the localizer on my 06 gly. Slope unusable right but they didn't read back the glideslope unusable or anything like that. Part of it. And I think what's really unlucky is They were quite far below. The vertical. Dissent profile that they should have been on.
41:21
Not in there were quite far below. Not like too ridiculous but right where they were there was a giant hill. Yeah. And also, some of the modes of the GPWS were disabled. Yes. Because otherwise it would go off in a new since way. So some of them were going off.
41:34
Yeah. But the terrain terrain and so on wasn't going off. Yeah. Probably another episode again. GPWS, they have this single terrain clearance floor which Yeah basically if you're in the landing config near an airport it kind of thinks well he's gonna land so We can turn off all our warnings.
41:51
Yeah, which is, yeah. And the I think the air traffic control have MYS, which is also to stop and flying sales, but because that hills in the way that it doesn't, it wasn't activated for that. So, There were would have been configuring their aircraft and in the normal ways and things like that and they must have felt what you can see in the transcript They felt like something wasn't right?
42:13
Yeah. That's always the first sign of an accident is like people describe The uncomfortable feeling, something's not right? And in the end they decided to go around but they sort of half-heartedly Started the go around manoeuvre and it just happened to be exactly the wrong point and they just smashed into right next to the VOR.
42:34
Yeah, I mean, they're like feet from the VOR where the impact the ground and I think 23 people survived. A couple of cab increase survive for everybody else, died. Say hundreds and hundreds of people. What can we all learn from? Well, yeah, I mean I mean, for in general, for the whole topic of the episodes, ILS, really easy really reliable, really good.
43:00
Old stonewater system, but does have its limitations. And some traps, as you say. So beware the traps but I think you nailed a lot of it there. In what you said was just resolving that ambiguity like just making sure, you know, everybody knows what we're doing and we're not looking at that gly slope.
43:22
If it's not working, we're gonna do this and we're going to stick with it and we're not going to be tempted, even briefing out that We this this thing is going to be drawing you to this. Like you're gonna be drawn to it and you're gonna want to fly down.
43:34
It is like You know, it's just the easy way is what we always do. It just blocking it out. Other options are available as well. Do you have to fly the localizer only? Yeah, you have to fly the ILS that day. Yeah, they weren't visual. Be, if they were clear about the approach they were doing and they were set.
43:52
The bottom lines were set. Yeah. Then they would know distance to the threshold. They're too low. And they need to go around the communication in the flight deck, you know? And the allocation of duties stream PF and PNF, if the PNF has they were called, then the pilot monitoring had the ability infin and say you're too low.
44:10
Go around, you know what the limits are. The guy had requested that the FO come in before the flight and they watch the brief in that's given by a trainer on Guam because he said, it's a black hole in this mountains in the way. So that's not like they were totally complacent and the guy, those suggestions that they're captains fatigued and he's not happy with the company because he so tired and so on.
44:31
And you can kind of see that in the accident. When she get, when she Once you pass a bottom line, when you're outside the SOP, all bets are off. You don't know whether you're in a risk, assessed situation or not. Yeah. So what are they doing? Are they following the SAP for a non precision approach while they following the SAP for the closed today?
44:49
Because they now all assume it's working. Even though the first officer and the Fly engineer seem to be quite clear that it's not working. Situation where they didn't get away with. With something because the hill was in the way. But you're saying something so reliable. So useful, so successful.
45:09
As an ILS. Yeah, when it goes wrong, it's almost unbelievable. We've almost become too trustworthy. In it. It's like an unreliable speed situation. It's like the instrument is can't be wrong. The closely can't be wrong. I've been taught our whole life, trust the instruments, don't, you know, and this all carry on into what however, aviation develops in the future, even when ILS’s disappear, this same accident is still waiting to happen because How reliability is GPS?
45:34
Everyone's got a GPS receiver in there pocket and they know that works all the time. Yet, another Korean aircraft was shot down because GPS was interfered with on that day. So, everything is always fallible. And the more successful and useful and the more rely on these systems The more complacent so you can creep in, I guess.
45:56
Good points to finish on good points. Finisher But, I look forward to my next ILS. Yeah, me send out. Appreciate a bit more on the America behind it. Get staff. Yeah, thanks very much. Cool.
