investigating ASL AUTO Crosswind Calculation Issues

[Mikaa]

Hi There,

Any updates for utilizing AUTO mode in crosswinds? It seems that the ASL is still not correctly calculating the offset required to track to the proper release point, and instead has the pilot fly a curved path (with seemingly unsafe bank angles) in order to meet the release criteria. This was reported back in 2021, but seems to still be present. 

 

 

Attached are two tracks made after today's most recent update. In both tracks, I attempt a level pass with 82Y in AUTO, to clearly demonstrate the present issues with the ASL calculations as TOF is increased in these conditions. Winds are 10kts at the surface, which aren't exactly 'gale-force' by any stretch of the imagination, and should be well within the capabilities of the jet to properly calculate the required steering.   

In the first pass, I attempt to follow the ASL as closely as possible (~500KIAS with ATC at 2000' MSL for both), and end up in a significant bank angle just to stay on the ASL by the release point. In the second pass, I attempt to 'Kentucky Windage' where the ASL should be steering (read tracking) me to, and can consistently get a better hit rate on the targets. 

F-18C 82Y AUTO Crosswind_1.trk F-18C 82Y AUTO Crosswind_2.trk

[BIGNEWY]

I have marked this investigating for now. 

Just to note also the high drag bombs should be delivered at a lower altitude and at a higher speed than demonstrated, also these are unguided so the CEP with higher winds will be greater, but I have asked the team about ASL Auto with a cross wind.

[Mikaa]

Thanks for looking into this. My tracks were really meant to show the need to chase the ASL as you approach the target, rather than flying a consistent wind corrected track to the release point. I can try it again at lower altitude and higher speed to see if anything changes, but I don't believe it'll make a difference to the guidance.

9 hours ago, BIGNEWY said:

...also these are unguided so the CEP with higher winds will be greater, but I have asked the team about ASL Auto with a cross wind.

Of course I don't expect JDAM levels of precision with high drag munitions, they were just used to show the movement of the ASL. This movement seems to be present in slicks too, but is very slight, as the TOF is short, and thus crosswind correction needed is minimal. 

 

Edit: Just tested again at 0.96M and 1500 feet, same issue - Track linked below. It can be flown, but the question is whether those steering cues are correct or not. Additionally, I tested it with slick Mk82's, and it doesn't seem to be an issue with wind. I even increased the winds to 40 kts at the surface - slicks still hit bang on with the ASL behaving as expected, giving steering cues for an appropriate track to release.

At those higher winds with the 82Y's, I can't even get a solution at .97M and 1200' MSL in afterburner. The ASL remains outside the HUD FOV at all times and I end up flying a circle around the target. Let me know if you need a track showing that. 

F-18C 82Y AUTO Crosswind_3.trk

Edited November 21, 2022 by Mikaa

[Mikaa]

Any updates to this? Still present in current OB, where excessive maneuvering is required to follow the HUD ASL for RET munitions, whereas slicks correctly account for crosswinds. 

 

@BIGNEWY - Seems some other Auto Bombing/CCRP-CCIP bugs are currently being investigated. Any chance this could be re-evaluated at the same time?

Edited April 15, 2023 by Mikaa

[Mikaa]

Any updates?

 

Let me be clear, the issue is specifically with the ASL drifting and being un-trackable with High Drag munitions, while slicks work correctly, even with wind present. This has nothing to do with the CEP of the various weapons. I can upload new track files if needed. 

[BIGNEWY]

Hi, no updates

I am going to have to run this by the team again. 

In our tests we are not seeing that much of a deviation, I am still unsure if a AUTO delivery should be used in this case with high drag munitions, better results can be had using CCIP 

 

[Mikaa]

Thanks for the response! 

If AUTO isn't capable of a correct ASL guidance with high drags because of lack of intended use, then this is totally understandable - goes beyond my expertise however, so someone more knowledgeable will have to chime in as to whether this is possible/intended steering cues.

Just seems like strange behavior that slicks have the correct crosswind accounted for in the ASL allowing for a near perfect track to the release point, but high drags make you follow this dramatic curved path. TOF differences aside, it appears to be way overcompensating for something. 

Thanks again for bumping this to the team.

[BIGNEWY]

We do have another report related to high drag that may be related. I will leave this tagged investigating for now and revisit again. 

thank you