acknowledged AIM-120 does not acquire target in HOBS if lock is not attained off the rail

[Default774]

AIM-120s fired in HOBS conditions do not acquire their target if the missile does not acquire the target instantly when coming off the rails.

In my test setup, I am firing a 120C at a target flying straight and level at varying degrees off bore. The name of the track denotes what degrees off bore the target was when weapon release was pressed. If the target is slightly (~1-2 degrees) out of gimbal limits, this means the missile will never acquire the target. 

120_hbs_38 - 38deg weapon release, 51deg motor ignition - 59deg first fin movement.

As you can hear on the friendly radio, the missile acquires the target practically instantly when coming off of the rails and has relatively little issue guiding onto the target and killing it in a practically over the shoulder shot.

120_hbs_40 - 40deg weapon release, 54deg motor ignition - 61deg first fin movement.

Despite only being a few degrees more off bore than the previous shot, the missile never acquires the target here. Likely due to the fact that the target was not within gimbal limits initially. Furthermore, the missile can be observed flying downwards, which is unusual considering the target and ownship are both flying straight and level, the missile should have no reason to fly downwards here.

Additionally, a few seconds after launch, the missile has manoeuvred enough to put the target pretty clearly within gimbal limits.

The target is flying straight and level, and the missile is being supplied correct and up-to-date datalink information. As the missile has an INS, is it not reasonable to assume that the missile should be able to guide itself onto the track of the target here despite it initially being out of gimbal limits? Aside from that, the missile should have plenty of energy and manoeuvrability to hit the target here, so I do not think this is an out of parameters shot.

120_hbs_40.acmi 120_hbs_38.acmi 120_hbs_40.trk 120_hbs_38.trk

[Default774]

To prove my point about this not being an out of parameters shot kinematically, here is a track with the target jamming, so the missile has no problems acquiring the target here. Aside from the strange (control damper?) behaviour here, this is literally an over the shoulder shot that hits its target perfectly due to it acquiring the target properly. This was only my second run trying these shots, you can definitely get the missile to go even further off bore than this.

https://streamable.com/q1d14a

120_megahobs.acmi 120_megahobs.trk

Edited February 22, 2023 by Default774

[Default774]

Issue still occurs in OB 2.8.4.48947 MT Preview

[BIGNEWY]

I have marked this acknowledge for now, the team will take another look in the future. 

We will need to have a think about this behaviour and look at the public evidence. 

thank you.