reported AIM-7 launch against rear-aspect target causes immediate loss of radar track

[Arctic Fox]

When employing Sparrows, the radar automatically switches from its regular PRF selection to HPRF PDI on launch. Against a hot target this is perfectly fine, but when attempting to engage a rear-aspect target, the switch from MPRF to PDI seems to almost always cause an immediate loss of track, with the target going into memory. This means that attempting to shoot a Sparrow at anything but a head-on target with the Hornet is borderline impossible right now.

There are a couple of problems here:

A. The radar's ability to maintain a rear-aspect target in HPRF should not be binary. If the target is near zero closure and over heavy terrain clutter then a failure to transfer the track to HPRF makes sense, but if the target is heavily separated from zero doppler and over little clutter, such as at high altitude or over water, it should be possible to maintain the track in HPRF.

B. From my understanding, with Sparrows selected the radar should continuously attempt to transfer the track to HPRF PDI even before a launch is commanded; this should provide some level of feedback on whether the missile should guide or not. It is also not currently possible to manually switch to PDI while in track, only in search.

If the transfer to HPRF does fail then launch should probably be inhibited. Alternatively the target should continue to be extrapolated until manually commanded to stop (IIRC this is what should happen with any lost track with AIM-7 in flight, but I'm not completely sure), or FLOOD mode should be engaged. Either way the current behaviour where pressing the missile launch button just immediately breaks your track and trashes your shot does not make much sense.

Tracks showing attempts to engage a Fitter and a Bear are attached. I did these tests over the ocean at relatively high closures which should have improved the probability of a successful track.

AIM-7 Fitter.trk AIM-7 Bear.trk

Edited August 31, 2023 by Arctic Fox

[Arctic Fox]

Additionally, there's a separate but related issue: If the track is dropped and you manage to reacquire the target in MPRF quickly enough, the missile will also reacquire and resume guiding on the target. Regardless of what the radar's PRF selection logic should be here, the missile should not be able to guide on a target with the radar in MPRF rather than in a missile illumination compatible mode (IE PDI).

AIM-7 MPRF Reacquisition.trk

[Esac_mirmidon]

I´ve found exactly the same problem.

Radar drops lock inmediate when bandit turns cold, everytime, no matter the range. 

[Raven (Elysian Angel)]

Yes, I noticed that too.

[BIGNEWY]

Please PM any public unclassified evidence of this behaviour. 

thank you

[Esac_mirmidon]

I dont have access at such information but i can share what is happening in DCS.

For example:

The F-18 drops radar lock at a bandit turning cold in RWS when launching Sparrows at less than 10 miles.

This is not happening when using TWS at the same range with the same missile, when STT at launch.

F-14B doesnt drop lock of bandits turning cold when launching Sparrows at less than 10 miles.

F-15E neither.

lf the F-18 radar is unable to keep a radar lock on a hot bandit under 10 miles just because is turning cold in real life........

[KenobiOrder]

Can this please get fixed. Its sort of a big deal. You cannot employ the sparrow at all in cold war servers because if the bandit turns cold or starts cold it instantly loses lock. 

[Solo_Turk]

I agree. aim 7 is so unusable. lost lock or doesn't guide at all most of the time.

[some1]

It is still a problem in 2.9.

Conditions in the attached track: 25k ft altitude, target is above me, closure rate is 300-400 kts. I fire four missiles between 7nm and 3nm and the radar is loosing lock every single time. 

On 9/7/2023 at 9:15 AM, BIGNEWY said:

Please PM any public unclassified evidence of this behaviour. 

https://www.af.mil/About-Us/Fact-Sheets/Display/Article/104575/aim-7-sparrow/

It says: "The versatile Sparrow has all-weather, all-altitude operational capability and can attack high-performance aircraft and missiles from any direction."

While in DCS Hornet it's effectively a front-aspect only weapon. And pray that the target won't make a turn.

HornetSparrow.trk

Edited October 21, 2023 by some1

[Solo_Turk]

there are some bugs about AIM 7 but the obvious one is this imo. if you have STT lock and shooting behind a target. radar goes to MEM mode immediately. even if you are at 3 nm away from IL76 target. other bug is that sometimes I shoot when I was on tws, radar goes stt but doesnt change prf to pdi, still guides the missle. sometimes it changes but doesnt guide the missile. I didn't get the logic and sparrow isn't usable effectively for F/A18C now.

aim7 bug.trk

Edited November 2, 2023 by Solo_Turk

[Tholozor]

A thread already exists for this: 

 

[Solo_Turk]

11 minutes ago, Tholozor said:

A thread already exists for this: 

 

so what? it's tagged wrongly as '' need evidence''. I wrote a comment in that topic as you can see. It is a neglected bug. Is there a rule saying if you shoot behind, your radar isn't capable to maintain lock?  this video can be an evidence, even  F4 phantom track and guide the missile to cold aspect target

 

[Solo_Turk]

at the meantime, F15E has the same missile and using it without any problem as far as I can see on youtube or twitch... they are asking evidence because they know we are not working for raytheon...

 

[Hulkbust44]

null@BIGNEWY This is incorrect, PM sent. 

If the radar dosen't see the target due to MLC for example, it will change the PRF to low.

 

[Raven (Elysian Angel)]

On 11/2/2023 at 11:22 PM, Solo_Turk said:

F15E has the same missile and using it without any problem

The F-14 uses it in rear-aspect without issues as well, even the AIM-7F works just fine :-)

[Solo_Turk]

we used to get stt lock from behind the targets at least, but now we don't even get the lock. It is going to HI prf and losing the lock. Instant mem mode. I'm not even talking about rear aspect AIM 7 shots. PDI is broken as well, it loses the lock instantly. come on guys you can do better. please solve this radar issues you made the jet like a 2.5 gen fighter...

f18 rear .trk

[Xhonas]

Hello there. Currently there are some issues with the APG-73 that makes it impossible to use the Aim-7 vs cold targets in the F/A-18 

First issue is: When you are in STT and shoot at a target with the Aim-7, the radar will enter the memory mode and eventually will drop the lock, despite being in ideal conditions to sustain a lock, making the Aim-7 lose track of the target.

Aim7 Cold target.trk

Second issue: If you are in TWS with the Aim-7 selected, if you fire an Aim-7, the radar should automatically command a lock on the target and switch to PDI. But thats not what happens. Instead, the radar maintains whatever PRF you had selected previously, and never switch to PDI, making it impossible to guide the Aim-7.

Aim7 tws to stt.trk

Edited January 3 by Xhonas

[Tholozor]

Already reported:

 

[BIGNEWY]

threads merged I will ask the team to take another look after the new year break. 

thanks

[TimSell75]

Here are two missions to test.

One is with Hot Aspect of an SU24. Shooting it down is no problem. PDI mode stays stable.

The other one is the same but with cold aspect, the SU24 flying away from you. As soon as you launch a Sparrow, the Radar goes into PDI and looses track soon after. This happens every single time, I have tested it 20+ times with the same result.

At the current state, the AIM7 is pretty much unusable in the hornet.

F18 AIM7 Cold.miz F18 AIM7 Hot.miz

[BIGNEWY]

Issue has been reported to the team for evaluation

thank you for the track replays