UNS on CBU103 Station

[flyco]

I recently had both CBU103s refuse to drop, with an indication on the DSMS of UNS, and the selections a solid white. Anybody know what I was doing wrong?

[Kimi_uy]

Maybe you're attempting to drop it below the minimum altitude setting of the profile.

[Tello]

iirc

You must wait for them to align when you are stationary. If you wait on the startup you will see that shortly after the 4.0.0.8 on the CDU you can notice that the UNS change to RDY in your DSMS

Edited May 27, 2015 by Tello

[shawnpatrick5000]

I've found that after some extreme maneuvering they will

Go out of alignment. After i've stabilized the CBU's will go into rdy indication. This usually takes only a few seconds. The cbu's don't align themselves, their driven off of the ins system. My understanding is the system will lock out the release of munitions if position is not within an accuracy threshold.

 

Ized

[flyco]

Thanks for the input. I was above 15,000ft and spent some time manoeuvring quite moderately, so I can rule out some of the suggestions. This leaves the suggestion that they did not ground align properly. I was very quick starting and taxiing to get into the fray so that suggestion is feasible.

 

The annoying thing is that the code UNS is not one described in the manual. It is a widespread problem in computing circles that strange errors are indicated that no-one seems to know the meaning of. Someone coded 'UNS' and presumably they knew why. It may be that the meaning is classified, but if anyone does know it would greatly ease my frustration. I can only think of 'unsafe', but why

[Dahlbeck]

I've had the same problem (unsure of DSMS indication though) with GPS/INS munitions after a quick start-up.

[david.lind]

The annoying thing is that the code UNS is not one described in the manual. It is a widespread problem in computing circles that strange errors are indicated that no-one seems to know the meaning of. Someone coded 'UNS' and presumably they knew why. It may be that the meaning is classified, but if anyone does know it would greatly ease my frustration. I can only think of 'unsafe', but why

 

I would put money on either UNStable or UNSecure.

 

Best / D

[david.lind]

I recently had both CBU103s refuse to drop, with an indication on the DSMS of UNS, and the selections a solid white. Anybody know what I was doing wrong?

 

From memory I think it also say's ALI or ALG close to UNS.

Which I read as Alignment Unstable.

Sometimes gentle sweeping turn's resolves this error in the DSMS.

But if your initial INS alignment is incomplete, it's hard to correct.

 

/D

[Tello]

Plz correct me if I am wrong - But as I understand you can select "Ground" or "Inflight" in the alignment options giving by the CDU upon start up. If one forgot or simply made a mistake not making sure the alignment has done it's job after take off - You can select "inflight" but it require one to fly straight for ten minutes(I am sure I have read this somewhere on the forum)

 

No matter the case. It is best to make sure the CDU read INS NAV READY/4.0.0.8 - select NAV, select EGI(Behind the stick) Arm the autopilot. And you are good to go.

 

From memory I think it also say's ALI or ALG close to UNS.

Which I read as Alignment Unstable.

Sometimes gentle sweeping turn's resolves this error in the DSMS.

But if your initial INS alignment is incomplete, it's hard to correct.

 

/D

[TIMBER SOUR]

There's lot of misunderstanding and incorrect advice posted above.

 

ALN UNS means Alignment Unsatisfactory. The EGI transfers position and rate data to the weapon using something called a Transfer Alignment. If the quality of the Transfer Alignment is poor, you will see Degraded or Unsatisfactory indications on DSMS.

 

To rectify a poor transfer alignment, you need to maneuver the airplane, specifically, make several large heading changes. Seeing ALN UNS is common on the ground while sitting stationary for 10 minutes in the EOR.

 

Regarding an in-flight alignment, this too requires you to fly a constantly varying flight path, with smooth constant rolling maneuvers to create heading changes. In-flight alignments do NOT require you to fly straight and level. Doing so would result in an unacceptably poor alignment.

[flyco]

In this case the caption ANS UNS came up while on the ground immediately,after a re-arming, on both CBU-103's. I have subsequently tried it several times with both 103 and 105, both before starting engines and after full INS alignment, with the same result. This was in multiplayer. When I tried in single player it was OK. Strange!

[TIMBER SOUR]

Again, ALN UNS is a normal condition when sitting stationary on the ground, or when flying for long periods in unaccelerated flight (straight and level). Make several large heading changes in order to increase the quality of the Transfer Alignment and regain the RDY indication.

 

I can't say for certain that DCS handles re-arming of IAMs without flaw, but generally speaking the indications you're seeing are easily explainable.

 

Of course, it goes without saying that IAMs require a platform (aircraft) EGI solution accuracy equivalent to a full gyrocompass (ground) alignment. So unless you see a 0.8 nm/hr EGI drift rate on the ALIGN page, IAMs shouldn't work.

[Tello]

I noticed that the status changed from UNS to RDY seconds after the CDU read 4.0.0.8.

Does this mean I am doing something in a wrong order with a cold ramp start ? I know it can be childish(It's just a game/sim) But I want to do things in a correct way just because the child inside me are truly a pilot :pilotfly:

 

Thanks for the clear up with all the technical expressions.

 

EDIT: no worries. I think I got it.

 

Again, ALN UNS is a normal condition when sitting stationary on the ground, or when flying for long periods in unaccelerated flight (straight and level).

Edited May 28, 2015 by Tello

[marluk]

I noticed that the status changed from UNS to RDY seconds after the CDU read 4.0.0.8.

Does this mean I am doing something in a wrong order with a cold ramp start ? I know it can be childish(It's just a game/sim) But I want to do things in a correct way just because the child inside me are truly a pilot :pilotfly:

 

Thanks for the clear up with all the technical expressions.

 

EDIT: no worries. I think I got it.

 

Probably. I'm waiting for 4.0.0.8 on CDU before changing to NAV and turning on EAC and RDR ALTM. After this procedure, I never had problem with ALN UNS again.

 

In flight I never noticed ALN UNS message if I had RDY message before.

Edited May 28, 2015 by marluk

[flyco]

Looks like you were right Timber Sour. I just ran a leisurely start with a CBU103, a CBU105, a GBU 31 and a GBU-38, requested as load. I waited for Align to show 4.0 0.8 and initially they were all showing UNS. After a few seconds the GBUs both went to RDY, while the CBUs went to DEG ( presumably degraded). After a further short wait they all went to RDY. as I taxied the CBUs went back to DEG.

 

My conclusion is that I need to wait for the full align before moving, and that as I move they may switch back and forth.

 

I'm just not sure that when I first encountered this in the air they all stayed solidly at UNS throughout the flight. Presumably because I had taxied before full alignment. More haste less speed, as my old granny used to say.

 

Thanks again. The problem with Forums (or Fora if you're a purist) is to separate the chaff from the grain - your input was genuine grain.

[Baxter]

TIMBER SWEET...thanks for the great info as usual TIMBER SOUR