not a bug INS alignment stops when throttling up.

[Lookiss]

I'm not sure if this is a bug or as intended. When you start the INS alignment, wait for RDY to appear in the DED. Then hit the wheel brakes and throttle up to about 80 or more, throttle down, the RDY disappears and the alignment stops. Maybe you're supposed to do the SEC test and the EPU test before starting the INS alignment. If so, it's not mentioned in the manual. See attached two tracks.

INS align lost.trk INS align lost2.trk

[Q3ark]

You shouldn’t do anything that may move the jet when aligning the INS, that goes for rearming too.

[Lord Vader]

Hello @Lookiss

The INS alignment procedures requires a completely stationary aircraft. Any movement or vibration may upset the internal systems and break the alignment. Like @Q3ark said, this can include even loading stores as it moves the aircraft slightly. Only move the throttle after alignment is complete and the knob is set to Nav. 

[SpecterDC13]

On 7/4/2024 at 10:13 AM, Lookiss said:

I'm not sure if this is a bug or as intended. When you start the INS alignment, wait for RDY to appear in the DED. Then hit the wheel brakes and throttle up to about 80 or more, throttle down, the RDY disappears and the alignment stops. Maybe you're supposed to do the SEC test and the EPU test before starting the INS alignment. If so, it's not mentioned in the manual. See attached two tracks.

INS align lost.trk 1011.4 kB · 5 downloads INS align lost2.trk 740.3 kB · 5 downloads

IRL SEC and EPU checks are done prior to anything else per the checklist which you can find publicly.

[darkman222]

As far as I can remember you can start up the engine while GPS is aligning, if you want to save time by overlapping processes. I have not tried it recently if its still the case tho.

But throttling up with engaged brakes will make the jet drop the nose slightly which will definitely throw off the GPS alignment.

[Furiz]

@Lookiss Hey, yeah as they have said above Alignment should be done while the jet is not moving or shaking.

Alignment also comes after EPU and SEC tests IRL, here is a good video of a real procedure done by Viper crew chief:

 

[WHOGX5]

On 7/5/2024 at 1:18 PM, Lord Vader said:

Hello @Lookiss

The INS alignment procedures requires a completely stationary aircraft. Any movement or vibration may upset the internal systems and break the alignment. Like @Q3ark said, this can include even loading stores as it moves the aircraft slightly. Only move the throttle after alignment is complete and the knob is set to Nav. 

This is incorrect. As soon as either a steady or flashing RDY is displayed on the INS page, you should be able to move your aircraft freely as it will automatically enter AUTO NAV mode, even with your INS knob set to STOR HDG or NORM. It doesn't matter if you're spooling up your engine, or you decide to taxi to the other side of the airfield, the alignment should not break. Then, once stationary again, the INS will automatically resume the alignment process without any actions from the pilot. The INS switch should only need to be set to NAV before takeoff, as AUTO NAV will only work on the ground. In fact, using these kinds of interrupted alignments should actually increase INS accuracy below 10, but this doesn't happen currently in the DCS F-16C either.

[Lord Vader]

9 hours ago, WHOGX5 said:

This is incorrect. As soon as either a steady or flashing RDY is displayed on the INS page, you should be able to move your aircraft freely as it will automatically enter AUTO NAV mode, even with your INS knob set to STOR HDG or NORM. It doesn't matter if you're spooling up your engine, or you decide to taxi to the other side of the airfield, the alignment should not break. Then, once stationary again, the INS will automatically resume the alignment process without any actions from the pilot. The INS switch should only need to be set to NAV before takeoff, as AUTO NAV will only work on the ground. In fact, using these kinds of interrupted alignments should actually increase INS accuracy below 10, but this doesn't happen currently in the DCS F-16C either.

Please supply any reference from unclassified official sources that supports your claim to @BIGNEWY via private message.

[WHOGX5]

On 7/8/2024 at 8:42 PM, Lord Vader said:

Please supply any reference from unclassified official sources that supports your claim to @BIGNEWY via private message.

DM sent.

[skywalker22]

On 7/8/2024 at 11:10 AM, WHOGX5 said:

This is incorrect. As soon as either a steady or flashing RDY is displayed on the INS page, you should be able to move your aircraft freely as it will automatically enter AUTO NAV mode, even with your INS knob set to STOR HDG or NORM. It doesn't matter if you're spooling up your engine, or you decide to taxi to the other side of the airfield, the alignment should not break. Then, once stationary again, the INS will automatically resume the alignment process without any actions from the pilot. The INS switch should only need to be set to NAV before takeoff, as AUTO NAV will only work on the ground. In fact, using these kinds of interrupted alignments should actually increase INS accuracy below 10, but this doesn't happen currently in the DCS F-16C either.

But he was correct about 1st part, that aircraft have to stay very still during the alignment process, even a little movement can interupt it.

[WHOGX5]

3 hours ago, skywalker22 said:

But he was correct about 1st part, that aircraft have to stay very still during the alignment process, even a little movement can interupt it.

Well, I'll extend an olive branch and say that he is partially correct. You have to remain stationary until the RDY indication is either flashing or solid, which will happen long before the alignment process is finished. After that you can move around freely, as the aircraft will automatically pause the alignment process while you're moving, and then automatically resume the alignment when stationary again. For a huge part of the alignment process, you can therefore move around freely. For a small part of it, you have to remain fully stationary.