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Problem with the INS position update

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I have real trouble updating the INS during flight. Of course I used the INS manual, but it didn't work, the index stays on 9/5.

Information about the "altitude" of the VOR's are also rare.

 

Since the Airplane already has some easy ways concerning the INS, what about an easy trick to update the INS?

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It does work -- you must be skipping some step.  Are you switching to mode 4 before attempting the update?  From page 25 of the INS manual:

 

2. Set data selector to DSRTK/STS. (If 1 ---X4 is displayed in right-hand data display, proceed directly to step 5.) 3. Press keyboard key 4. Ensure that 000004 appears in right-hand data display and that INSERT key is lit before proceeding to next step. 4. Press INSERT key. (INSERT key goes out. Data displays return to normal with 4 appearing in last digit of right-hand display.)

 

The index will then read 9/4 and after the rest of the procedure is followed the 9 will begin to decrease.  Because you state the display stays at 9/5 I think that you are missing the set to 4 step. 

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These are the steps that i follow to update my INSs systems:

1: i Set the knob in the WAYPOINT position

2: i set the Waypoint little wheel in 1 position

3: i press simultaneously 7 and 9 keys (clicking first on 7 with right mouse button and than 9 ever with right mouse button)

<-- At this point the Display shows 0es in latitude and longitude

4: i instert latitude pressing before the north (2) or south (8) buttons, according to my latitude, and insert.

5: i insert the longitude pressing before the west (4) or east (6) buttons, according to my longitude, and insert.

6: inserted latitude and longitude, i press simultaneously keys 3 and 9

<-- Again, 0es appears in the Display -->

7: I press 2 or 8 button, both are useful for the same thing, and than i insert the altitude of the VOR rounding to 5 (if the VOR is 1200fts high, i simply press 1 to indicate 1000fts, if is 1700fts high, i press 2 to indicate 2000fts, if is 12500 high, i press 12 to indicate 12000fts), and i press insert.

8:I press 4 or 6 button, both useful again for the same thing, and i insert the frequency of the VOR (if it's 113.00, i press 1, 1, 3, 0, 0), then insert

<-------------------> At this point all informations are inserted in the INS to update<---------------->

9: i Turn the Knob to the DISTANCE position

10: I Set the VOR frequency in the NAV radio corrisponding the INS that i'm updating (if INS1, i set the frequency in NAV1, if INS2, i set in NAV2), assuring the radio capture the frequency and shoes in the DME indicator the distance from/to the VOR.

11: i check if the distances in the DME indicator and in the INS are similar (for example, 44nm in the DME indicator and 46 in the INS, they're near each others)

12: I turn the knob again in the WAYPOINT position, than i press WAYPOINT CHANGE key in the middle of the INS, and than i press 1 (that is the waypoint corrisponding the DME station i inserted, concerning the waypoint wheel at step 2)

13: i turn the Knob in DSRTK/STS position, and than i press the 4 Key

<-------------At this point on the right display appears 000004-------------->

14: Finally i press insert button

 

Now my INS is starting to update, and i will see the progress in the decimal decreasing gradually to 1

Hope i wrote all correctly and i've been exhaustive, good luck!

  • Upvote 1

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I found a note in DC-8 manual regarding Position check/position update:

 

NOTE: before and during ocean crossing, INS updating should be made only

            when a position error exceeding 5NM has been determined by

            accurate fix, preferably using VOR/DME

 

 

This is just an info that position error limit should init INS Update not PI according the manual .......

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On 10/8/2018 at 9:36 AM, FedeSuper10 said:

These are the steps that i follow to update my INSs systems:

 

Your post was helpful to me.  Thank you!   Sometimes I could get it to update, other times no.

 

I just did a flight from Lisbon (LPPT) to Rio de Janiero (SBGL) and my flight plan took me over Fernando de Noronha islands -- I used that VOR to update.

Interestingly it looks like the Fernando VOR has been moved ?? vs. the 2006 navdata.  Anyway, thank you again.

 

 

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On 10/14/2018 at 11:19 AM, AAC47 said:

I found a note in DC-8 manual regarding Position check/position update:

 

NOTE: before and during ocean crossing, INS updating should be made only

            when a position error exceeding 5NM has been determined by

            accurate fix, preferably using VOR/DME

 

 

This is just an info that position error limit should init INS Update not PI according the manual .......

It's impossible to update the INS during the Atlantic Crossing, there is no VOR/DME to use, the better you can do is to update it (and keeping it updating) at the last VOR you pass nearby before starting the Atlantic Crossing, and to re-update it once again when you're arriving in the other side of the Atlantic, with the first nearest VOR.

 

On 10/15/2018 at 7:23 PM, Mace_RB said:

 

Your post was helpful to me.  Thank you!   Sometimes I could get it to update, other times no.

 

I just did a flight from Lisbon (LPPT) to Rio de Janiero (SBGL) and my flight plan took me over Fernando de Noronha islands -- I used that VOR to update.

Interestingly it looks like the Fernando VOR has been moved ?? vs. the 2006 navdata.  Anyway, thank you again.

 

 

You're welcome :D

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If the position error is within limit I can't understand why You have to update INS

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