Mark point as ILS

[Lee1]

I was reading an F16 combat book and read that the guy put a mark point on the end of a runway at an airfield with no approach aids and proceeded to fly a false ILS approach from it using the aircraft systems to simulate the G/S and C/L.

Can we do that in DCS please?

Thanks

[Moonshine]

You can by using an OFLY markpoint.

from there the GS can be held using the OFLY wp as a reference.

also remember, the one setting the OFLY markpoint had to improvise all the way to even set that point for the others to then follow and make use of it.

by setting multiple OFLY markpoints along the descent you can improvise a glideslope, so the following planes just fly from markpoint to markpoint at a given speed 

Edit: since creating OFLY markpoints sets them at sea level (MSL), youll have to change its elevation to the desired value manually, so they appear at the right position in your hud

Edited March 28, 2023 by Moonshine

[Lee1]

Thanks very much!

 

[JuiceIsLoose]

No additional solution. But is the book "Viper Pilot" by John Pruden? Currently reading/listening to it and just got past that chapter where he did that.

[_SteelFalcon_]

15 minutes ago, JuiceIsLoose said:

No additional solution. But is the book "Viper Pilot" by John Pruden? Currently reading/listening to it and just got past that chapter where he did that.

pretty sure Viper Pilot is by Dan Hampton, but yes, there's a part in that book with exactly this scenario

[JuiceIsLoose]

1 hour ago, _SteelFalcon_ said:

pretty sure Viper Pilot is by Dan Hampton, but yes, there's a part in that book with exactly this scenario

You are correct!! The audio book is read by John Pruden. My bad. Great Book! Definitely got me out of the hornet and into the viper for a few weeks.

[whiteladder]

Just to be clear does this mean you can`t couple the ILS to a Markpoint?  

 

[Moonshine]

no you cant.

ILS (the system) is a beacon (well several beacons) on an airfield. 

the ILS has two main components

- Localizer,

- Glide path/ slope.

The localizer gives the aircraft lateral guidance. It tells the pilot where the centre of the runway is, by signalling the pilot to move either to the left or to the right through a cockpit instrument (vertical needle)

The glide slope or the glide path provides the pilot with vertical guidance. The glide slope is set such that a glide slope angle maintained by the pilot. The horizontal needle of the slope moves up, if the aircraft is too low and moves down if it is too much above the required path.

 

the method described here in this post is a "makeshift instrument approach" (this is NOT ILS, you wont get any needles to help you) for an airfield that does not support ILS guidance. by creating different OFLY markpoints at specified altitudes you can create a makeshift approach by then flying along the set markpoints using your instruments only. the aircraft setting those markpoints in the first place will likely have to go around

Edited March 29, 2023 by Moonshine

[whiteladder]

So I think the OP is refering to a incident from the Book Viper Pilot where Dan Hampton talks about coupling the ils to a Markpoint. This is related to a incident where he recovered group of F16 to a divert airfield, which had no published ils approach. The direct quote from the book is:

Quote

Since my wingman and I both had enough fuel, there was only one option. I’d fly us down to the end of the runway using GPS guidance and take a MARK point, a precise latitude and longitude for whatever piece of ground I chose. It could then be coupled with the aircraft’s Instrument Landing System and would generate horizontal and vertical steering to that point on the ground.

Dan Hampton states he could have data linked this to the rest of his make shift flight, but past the lat/long verbally for them to generate their own markpoints to couple their own ils.  It certainly is implied that this mark point is being use to drive the ils needles instead of the normal ils signals.  

Another quote later in the same chapter confirms this

Quote

At about eight miles, the little horizontal bar on my ILS symbology fluttered and began its slow drop. This was the glide slope, the controlled descent, that I had to maintain to the runway. The other bar, a vertical one, would keep me lined up on the runway. I checked the HUD against the larger, old-fashioned round-dial instrument on the console, and they showed the same indications

So I guess there are 2 questions does our dcs f16 version have this feature irl and is it modelled in game?

[Moonshine]

you have got a point.

interestingly and i think this is NOT modelled in DCS at its current state, is the quote about coupling the needles to get guidance to that (i assume OFLY) markpoint he set (as in, surely you cant make one with the hud and neither with the TGP or AG radar as you cant see a thing until he basically flew over the runway, so OFLY seems logical). might have to dig in some manuals

i believe the function we are looking for is called "command steering" (ILS Flight Director). the use of the Horizontal and Vertical Steering Bars is not only for an ILS approach but also for example used in LADD and CCRP loft according to some manual that should not be named in the forums. so having ILS on would provide guidance using the needles for course deviation on a CCRP loft for example. 

while "CMD STRG" is shown on the DED, it can currently not be activated/deactivated using MSEL (0). maybe one day it will be implemented

 

Edited March 29, 2023 by Moonshine

[Frederf]

On 3/29/2023 at 7:25 AM, whiteladder said:

It could then be coupled with the aircraft’s Instrument Landing System

There's no such thing. The Hampton book has all sorts of stuff that's just plain wrong or at best carelessly worded. You can't get ILS-type guidance on anything but ILS. You can can use the CDI on the HSI on an INS steerpoint but that's the same as TACAN, would be horizontal only on the HSI, and without any explicit vertical guidance a la ILS. Command steering is a guidance symbol for ILS which gives advice on where to put the FPM but in no way can be coupled (in the aviation sense) to the autopilot. It must be hand flown. And this feature only works with genuine ILS.

In a pinch you could absolutely use for example the FCR to put a cursor at the beginning of a runway or type in the coordinates and make a "poor man's ILS" but it would not be indistinguishable from the normal ILS presentation at all. There would be serious limitations in presentation beyond the downsides of an INU vs a radio beacon in terms of confidence of position.

[Aquorys]

What I usually do for makeshift instrument approaches is to put a steerpoint near the runway threshold (e.g. for the Caucasus map, there are coordinates in the kneeboard), and then I calculate the altitude at various distances using the airfield elevation and the distance from the steerpoint during my approach using whatever approach angle I want. Usually that would be approximately 3 degrees, unless there is high terrain, where it would typically be 5 to 10 degrees.

To execute the approach, I just put the flight path marker close to whatever my approach angle is supposed to be and check my altitude at the previously calculated distances from the runway threshold steerpoint for any corrections until I'm visual with the runway (or I'm not and need to go around or possibly go elsewhere). Somewhat like an RNAV approach, except you have to hand-fly an improvised glide slope. The whole thing isn't much different from flying the full instrument approaches on the Nevada map, before you're established on ILS, using TACAN instead of the runway coordinates. That is also just hand-flying a glide slope based on predetermined altitude/distance information, until you switch to the ILS around ~7-ish miles out.

[S]

On 3/29/2023 at 6:35 AM, Moonshine said:

you have got a point.

interestingly and i think this is NOT modelled in DCS at its current state, is the quote about coupling the needles to get guidance to that (i assume OFLY) markpoint he set (as in, surely you cant make one with the hud and neither with the TGP or AG radar as you cant see a thing until he basically flew over the runway, so OFLY seems logical). might have to dig in some manuals

i believe the function we are looking for is called "command steering" (ILS Flight Director). the use of the Horizontal and Vertical Steering Bars is not only for an ILS approach but also for example used in LADD and CCRP loft according to some manual that should not be named in the forums. so having ILS on would provide guidance using the needles for course deviation on a CCRP loft for example. 

while "CMD STRG" is shown on the DED, it can currently not be activated/deactivated using MSEL (0). maybe one day it will be implemented

 

 

I would assume this is what he's describing (poorly) in the book. 

My reason for believing this would be what he's talking about is that the true ILS avionics in the aircraft take input from stationary ground stations and move the needles depending on how the radio signal is reaching the jet's antennae. There's no ground stations to interact with the markpoint, so you wouldn't be able to use the actual ILS system with a markpoint. 

That being said, most AP systems (at least in the civilian side) show the magenta lines (which could roughly equate with the needles in the Viper) based on GPS or other data but they're normally called 'flight directors'. They visually do the same thing, but the computations aren't based on a glideslope and lateral localizer. 

If I were to try to do this in DCS (with what we have now) I would go the route of dropping the markpoint then overflying the runway on opposite heading and drop a point 10NM away from the runway end. Add an elevation of +3183 AGL (at end of runway) to this steerpoint and you have a 3-degree descent from that point to the runway. You wouldn't get the needles as we don't have non-ILS FD in the Viper, but you could fly to the 10NM markpoint and switch over to the runway point and fly an AoA approach that way.

[Chain_1]

To make it easier on yourself use 3000' at 10 mi (1 deg = 100 ft/mi) since math kills lift.  If you look into the 60:1 rule, there's a bunch of things you can mentally figure pretty easily if you round a bit, i.e. 1 NM = 6000' instead of 6076'.  It's all close enough.  Technique only.

[S]

On 4/8/2023 at 3:18 PM, Chain_1 said:

To make it easier on yourself use 3000' at 10 mi (1 deg = 100 ft/mi) since math kills lift.  If you look into the 60:1 rule, there's a bunch of things you can mentally figure pretty easily if you round a bit, i.e. 1 NM = 6000' instead of 6076'.  It's all close enough.  Technique only.

I built myself a calculator app, so don't mind me. 

[SickSidewinder9]

Yeah, the book implies there's some kind of built in ILS that they used to shoot the approach, but maybe they just held the markpoint at the 2.5 line on the HUD.  I think the version in the book is a later version though, so maybe it's got some more nav aids built in.

[Aquorys]

On 4/8/2023 at 4:29 AM, S said:

I would go the route of dropping the markpoint then overflying the runway on opposite heading and drop a point 10NM away from the runway end

You could just dial the HSI to the runway heading and use the indications on the HSI for lateral navigation. It also shows the distance from the steerpoint in NAV mode, so you can check your actual altitude vs. the altitude that you should be at when you pass 10 nm.

[S]

On 4/10/2023 at 2:44 PM, Aquorys said:

You could just dial the HSI to the runway heading and use the indications on the HSI for lateral navigation. It also shows the distance from the steerpoint in NAV mode, so you can check your actual altitude vs. the altitude that you should be at when you pass 10 nm.

I thought the post I was replying to mentioned multiple points - re-reading it I was wrong. Yeah, this would work and is more likely for what was described.