How to recalibrate INS in the air

[Eduard Gasull 258]

I have noticed, that INS is losing precision via DSRTK mode, from 0  to 7 again. 

 

How i do to avoid this or to recalibrated the INS with the plane in the air moving?

 

Cheers

 

[Michael2 236]

The performance index number (I think that's the right phrase) is not an exact measure of the degree of position inaccuracy.  The number will get bigger as a function of time to indicate a sort of worst case scenario.

 

Nevertheless, the accuracy of the INS position does degrage over time. To improve it, you need to carry out a DME update.  See the INS manual, figures 6 and 7 (pages 23 to 26).  There are two steps to this process.  First you need to enter the DME station position into the INS.  You need a DME within range that you can tune with the NAV radio.  Ideally it will be one offset from your flight path.  So out in front and off to one side. Then you follow the procedure in the manual to enter the latitude, longitdude and elevation of the DME station.  You are going to charts or some kind of navigation addon like Aivlasoft to get the position data -- I note the P3D map doesn't give you this. When you enter the data you must first choose a DME ID# using the little black wheel on the INS. Any number other than zero is OK.  When the airplane loads it's set to one.

 

Once you have got the DME position entered (which can be done at any time during your flight) you can then set the INS to "aided" mode - figure 7.  Then your performance index will gradually move to a smaller number as the INS position updates.  You must keep your nav radio tuned to the DME while updating.  You can verify that the update is working with the shift-4 popup gauge. One of the green lights will be on if the update is working.

 

When the manual tells you to press two keys together, you need to right click them one after the other.

[Eduard Gasull 258]

I follow this but for any reason, I'm doing something wrong i will still try

[Eduard Gasull 258]

For some reason, i can't figure out why the INS is not updating. I know i can boring someone, but could you please or somebody write the exact steps and buttons to press to do it?

thanks

best regards

 

Eduard!