I used to do atlantic crossings with the Civa INS in FS9. The precision is not too bad. After a couple of hours without DME updating, I had an offset of maybe 4-5 nautical miles. So it's possible

well as i understand after several hrs of flight it is still possible to arrive in range of some coastal beacon, and then use radio navigation. sounds good, now i gotta buy 707

Markoz wrote on Dec 18^th, 2011 at 12:38am:



I think you need 2 units working to get them to update to a VOR.  There are some notes here about mods for dual use.

To update, do the following:

1. tune in Nav2 (not Nav1) to the in range VOR.
2. Get the long/lat of the VOR station from the chart or other source.
3. Select WPT and pick any number (say 1).
3. Right click on #7 and then #9 (you will see the WPT go to zeros.)
4. Enter the long/lat from above.
5 Once entered click INSERT WPT #1 enter.
6. check for the green light. Should be DME updating now.

Thanks for confirming, I have never used it with less than 2.

I'm with you, Mark.  I have tried DME updates to the single INS on my 707 and it has never worked.  I follow the CIVA checklist step by step and at the end I never get the green light.  With 2 or 3 INS heads I can follow the same checklist and have successful updates every time.

Jim C

From OperationsManual.pdf page 13 -

3 DME POSITION UPDATING

The INS positions may be updated by a single or dual DME (Distance Measuring
Equipment). Optimum single updating may be obtained selecting a DME station “off
track”, at least 15 NM off the intended track, and within 200NM of range. Optimum dual
DME updating is obtained tuning a second DME along track. INS 3 does not require DME
data insertion, since the INS 3 receives DME updating from INS1 and/or INS2. Tuning
both VHF NAV on the same frequency will not improve the single DME updating both in
efficiency and velocity.

This tells me it CAN be done. So I follow the instructions that follow this, but I really think that where it says on page 14:
Tune on VHF-NAV panels (n°1 and/or n°2) one DME or two DME stations, for a single or
dual DME updating as desired. INS 1 is connected to NAV 1 and INS 2 to NAV 2.
is where I become unglued when attempting to update. I seem to get a lot of trouble finding the DME station to enter, so I never seem to get it updated.

I know CoolP provided some great info in the CIVA INS - THE ONLY THREAD PLEASE (starting at reply #149 through to reply #158) on how it is done, but I still wasn't able to do it. I tried to achieve this twice, but I'm not sure I ever tried it again after those failures. I felt it best to do the same route, SEA - HNL (KSEA - PHNL), where I had all the data written down, so as to achieve a result. I'm pretty sure I also tried it on a flight from MEL - NAN (YMML - NFFN), but I failed again.

What is really strange here is that I have picked up something CoolP put in his reply (#154) that I must have completely overlooked or misunderstood, that now makes sense so I will try again. It has to do with the plan converter and the ADC file for the flight plan. I somehow thought they went into the plan and I somehow had to take the waypoints out of it so I wasn't doing some zigzagging in the flight. It's amazing when you read something, after you haven't read for a while, and it now makes perfect sense! I'm off to try SEA - HNL with this newly discovered (for me) info!

So here's hoping it works.

Mark

Since I am a newbe in the 707, I have not flown on the INS yet but have loaded lat/longs to it and played with the controls to verify it works correctly. I have had the CIVA INS installed in an AFG Beach 300 for a while and I use it regularly since it will allow me to fly a track out and back to the same airport, I use VOR1 to calibrate. It is set up as a single CIVA and works just fine. I will admit that I must use the manual every time to set up the updating as any variation from the procedure will cause it to malfunction. The programming was definitely created for someone who loves to follow process sheets  

Dave