Bassel & Incirlik : ILS bugs

[zb2oby]

Hi, 

i'm experiencing issues with some ILS approaches on Syria map : 

 

 

With DCS 2.7 & 2.5.6

With Mirage 2000-C.

With a setted wind from 180° / 8kts.

 

After several tests, here my observations : 

 

Incirlik

With ATC Clearance for RWY 23

 

- RWY 23 (ILS 111.70) : KO => No ILS signal...

- RWY 5 (ILS 109.30) :

• ILS signal => OK
• LOC => OK
• GLIDE => OK

Bassel El-Assad

With ATC Clearance for RWY 17R

- RWY 17R (ILS 109.10) :

• ILS signal => OK
• LOC => OK,
• GLIDE => KO (no Glide slope)

 

 

Edited May 21, 2021 by zb2oby
edit wind

[Ramsay]

2 hours ago, zb2oby said:

With Mirage 2000-C.

With a setted wind from 180° / 8kts.

 

After several tests, here my observations : 

 

Incirlik

With ATC Clearance for RWY 23

 

- RWY 23 (ILS 111.70) : KO => No ILS signal...

This is a general DCS problem introduced with 2.5.x where ATC's active runway and active ILS desync (at most AB) when there is a moderate headwind (1-6 knots).

 

Here the 8 kts / 55° crosswind gives a RWY 23 headwind of 4.6 kts (8 x cos (55°)), increasing the crosswind to 10 knots fixes the ATC/ILS desync as 10 kts x cos (55°) = 5.7 kts which is enough for Incirlik's ILS to switch to RWY 23.

 

2 hours ago, zb2oby said:

Bassel El-Assad

With ATC Clearance for RWY 17R

- RWY 17R (ILS 109.10) :

• ILS signal => OK
• LOC => OK,
• GLIDE => KO (no Glide slope)

I confirm the missing ILS glide slope signal at Bassel Al-Assad

 

Tested Open Beta 2.7.1.6430

 

 

Edited May 21, 2021 by Ramsay

[zb2oby]

Hi, 

 

Thanks for the reply,

 

I've tried with 10kts. It seems not enough... I've No RWY 23 ILS signal.

 

I've made a test with 180°/12kts. So headwind of 6,8kts (12x cos (55°)) and it works. 

 

So, according to this test and other thread i've read on this forum,  i think the value which fix the desync is around 7kts.  But i thought it was the crosswind not the headwind. Now i'm aware ^^

 

Thank you for pointing me in the right direction ^^

 

For Bassel El Assad i hope it will be fixed soon.

[Scandfox]

Strange that wind shall trigger use of ILS....InstrumentLandingSystem is used to facilitate landing in Instrument condition and that is low visibility ,

 

Foggy/Hazy cinditions often have winds below 6 knot so in this case You can't use ILS when You really need help for a safe landing

 

Can anyone explain this logic for me pls......??

[Ramsay]

On 5/22/2021 at 9:48 AM, Scandfox said:

Can anyone explain this logic for me pls......??

AFAIK ATC's active runway direction and the ILS used to be coupled i.e. once there was a tailwind of ~6 knots (3 m/s), ATC would change the active runway direction and turn off the ILS for the opposite direction (regardless if it was the only system/direction or not).

 

This was somewhat logical as, Caucasus airports often use common frequencies for both directions with a change in audio ID's to confirm the active ILS/Marker direction (if the opposite direction did not turn off they would interfere with each other).

 

DCS's ATC has never supported flying a localiser "back course", though you could always ignore the AI's instructions if the signal was present.

 

This changed with DCS 2.5.0 and the active runway and ILS logics were separated.

 

Unfortunately the logic for the 2 decisions isn't consistent and DCS's ATC can, and often does, choose (desync) different directions for the active runway and the ILS when there is a moderate headwind 1-6 knots (1-3.5 m/s).

 

This effectively breaks the ATC/ILS combination in any "normal" mission made using realistic METAR data or dynamic weather unless the mission creator/player is extremely lucky.

 

Surprisingly (for a combat flight simulator) fixing this is a low priority for ED and is something we've had to learn to live with (I gave up trying to using real world METAR data 3 years ago).

Edited May 25, 2021 by Ramsay

[Scandfox]

Thanks for Your explanation and as You wrote we have to learn and live with it...

 

I fly with NOSIG, a Swedish group and I use their server for ILS training, direct landing and ILS with Circling approach to opposite runway

 

brgds/

Scandfox