cannot produce and mssing track file Odd Data Link Inconsistencies based on MP server

[BluesRocket]

I have been flying the Viper since June, and in August joined a nice mil sim type squadron. We have been in a training cycle and just entered a mission cycle. One thing that has been plaguing me (and only me it seems) is that despite a startup sequence that has been observed multiple times, in almost all weekend training or missions on our multiplayer servers, my INS is either screwed up and needs to be recalibrated in flight, and/or my DataLink is not showing any other aircraft on my MFD. If I go into practice alone or with one or two other people, I can get both INS and datalink working just fine. But when we get into a full squadron training or mission with the entire team, usually one or both systems are hosed.

I have streamed multiple time and had my startup sequence observed. On two occasions this behavior was repeatable, but not consistent EVERY time.

This is taking away from enjoyment of the game but we are baffled. Note: if I play on outside MP servers, I NEVER have either problem when starting from a cold jet, and never have problems with single player missions or campaigns. Weird.

Thanks for listening and considering these issues.

[razo+r]

Do you have a short track perhaps?

You say you don't have this issue in singleplayer. Are you trying to reproduce it with the exact same mission in which you have the problem?

[BluesRocket]

1 hour ago, razo+r said:

Do you have a short track perhaps?

You say you don't have this issue in singleplayer. Are you trying to reproduce it with the exact same mission in which you have the problem?

Yes. In fact we're going to try again to reproduce. Sometimes, I find I can at least get the DL issues resolved by going into the DED and turning GPS time off/on a few times. As for INS, with these problems, and inflight alignment can fix it if I can keep the jet level (asymmetrical loadouts can be a problem). We're all just baffled and getting pretty frustrated.

And I DON'T have this problem on servers outside the Squadron's. My GUT tells me it's something in the way the mission is being developed but I know nothing about creating multiplayer missions and how a data cartridge might be used for a given flight of 2-4 F-16s... And today, a few others had DL issues as well.

[razo+r]

Feel free to upload the mission here so we could take a look and try to reproduce it ourself.

[MeanJim]

Are you turning the MIDS LVT switch on before you have a GPS signal?  The manual's after engine start checklist states:

• The MIDS LVT knob should only be set to ON after the GPS receiver has been powered and the GPS timing signal has been received, indicated by “GPS SYSTEM” being displayed on the TIME DED page. 

You can also check the NAV status DED page (4 on the ICP keypad) and make sure SYS and GPS accuracy are high.  If you start out in a hangar, this can block the GPS from getting a signal and your datalink will not work.  Wait until after INS alignment, the taxi out of the hangar and wait for GPS signal status to show HIGH and then turn the MIDS LVD switch on.  If you forget, you can simply turn it off and back on to get it working.  This was fixed a patch or two ago, but seems to have broken again.

As for your INS issues, the most common mistake I see people do is arming the jet during alignment.  The movement during armament can mess up your alignment.  If you're not doing that, you can post a track of your startup procedure.

[Sarge55]

Any mods?

[BluesRocket]

Folks, after a bit of experimenting we've discovered that INS/DL issues are occuring (occasionally) while startup is performed inside the hanger. It's easy enough to correct, and if necessary for INS it can be performed in flight. Once the throttle geso idle and warning lights are off, pulling forward to expose the full canopy glass seems to be enough to turn GPS off and on and get the signal. If INS is hosed it can always be realigned in flight. Thanks for the feedback!

[darkman222]

The GPS time on and off for DL issues is a hassle as a fix. I would like to know why that happens too. It also happens on public servers and flying on custom missions with the squadron I am flying with.

Secondly: Doing an inflight align with GPS is no option in missions that have push times and time on target.

What do you mean by "INS hosed" is it just inacurate after some flight time, or is it totally unusable right from the start? I had created a thread about INS drift over time, which was corrected. It seems to be in allowable drift values often, but sometimes I still have the feeling that INS drifts way off allowable limits.

That hangars block GPS signal is a feature, that came to DCS like half a year ago, and represents real life GPS limitations.

Edited Tuesday at 04:33 PM by darkman222

[BluesRocket]

On 11/25/2025 at 11:32 AM, darkman222 said:

The GPS time on and off for DL issues is a hassle as a fix. I would like to know why that happens too. It also happens on public servers and flying on custom missions with the squadron I am flying with.

Secondly: Doing an inflight align with GPS is no option in missions that have push times and time on target.

What do you mean by "INS hosed" is it just inacurate after some flight time, or is it totally unusable right from the start? I had created a thread about INS drift over time, which was corrected. It seems to be in allowable drift values often, but sometimes I still have the feeling that INS drifts way off allowable limits.

That hangars block GPS signal is a feature, that came to DCS like half a year ago, and represents real life GPS limitations.

INS hosed as it's not operating after what appears to be a normal, successful start and nothing can be done to get it operating. It's happened to me a few times in the squadron missions, and the last one played apparently hit several other flyers as well. So far no pattern is emerging and no errors we can see in the logs. It almost always affects someone during a mission.

[darkman222]

I would be interesting if you did a video recording during the mission to see whats happening and how the failure shows in the jet. Trackfiles are pretty huge in a MP mission.

But the problem only ocurrs during startup right? Never in flight? So if it works, it works the rest of the mission, right?

Edited yesterday at 07:59 AM by darkman222

[BluesRocket]

1 hour ago, darkman222 said:

I would be interesting if you did a video recording during the mission to see whats happening and how the failure shows in the jet. Trackfiles are pretty huge in a MP mission.

But the problem only ocurrs during startup right? Never in flight? So if it works, it works the rest of the mission, right?

Yes, if it works at startup there are no issues. We've seen drift occasionally but in flight INS alignment usually fixes that quickly enough.