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737NGX drifts off course


newtie

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Hi all-

 

I had this issue way back when and forgot what I did to fix it.

 

Set flight plan KLAX-BSR-KSFO, take off and climb, VNAV/LVAVAP all set and lit as usual, jet just drifts/ will not follow course.

 

Reinstalled the NGX after installing P3D3.0 so I'm assuming all service packs are included in the latest install.

 

Did not have this problem in 2.5

 

Any ideas?

 

Thanks,

Mark

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Reinstalled the NGX after installing P3D3.0 so I'm assuming all service packs are included in the latest install.

 

Did you download the newest installer that was made for P3Dv3, or did you use a migration tool?

 

Also, it doesn't matter what is "lit" on the MCP. What does the FMA (flight mode annunciator - top of the PFD) say?

 

 

 

Final note: full names -first and last - are required in each post in the forum here.

Kyle Rodgers

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Hi Kyle-

 

Latest download version from PMDG site.

 

What I was referencing with everything being lit was that there were no procedural changes (that I know of) from the same identical flight in 2.5

I'll check the FMA later today.

 

If I recall correctly, this drifting issue had something to do with ASN way back when. They had given specific directions to those who were experiencing this problem. I'm using their current beta for P3D.

 

Thanks,

Mark Jones

Order# [Removed - don't place order IDs in the forum, please]

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If I recall correctly, this drifting issue had something to do with ASN way back when. They had given specific directions to those who were experiencing this problem. I'm using their current beta for P3D.

 

Yeah, in the past, it was a turbulence thing from ASN (and FSX weather for that matter). Try it without ASN. If it solves the issue, let HiFi know to have a look into it through whatever avenue they use for beta feedback.

Kyle Rodgers

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If that doesnt work, try to align the IRS s correctly before takeoff. Then try to hit the first waypoints. Typical route KLAX KSFO would be the Ventura5 departure to Ventura, then San Marcos RZS, then either BSR or SERFR.

 

There are no VORs in the ocean and this makes it harder for the IRSs to track the aircrafts position unless you hit the waypoints.

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Hi Alberto-

 

I've always done KLAX > BSR > KSFO with 2.5 without problems.

 

I'm going to try without ASN when I get home tonight and see if that's the problem.

 

I'll come back at some point if no joy.

 

Thanks,

Mark Jones


Yeah, in the past, it was a turbulence thing from ASN (and FSX weather for that matter). Try it without ASN. If it solves the issue, let HiFi know to have a look into it through whatever avenue they use for beta feedback.

Thanks.

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If that doesnt work, try to align the IRS s correctly before takeoff. Then try to hit the first waypoints. Typical route KLAX KSFO would be the Ventura5 departure to Ventura, then San Marcos RZS, then either BSR or SERFR.

 

There are no VORs in the ocean and this makes it harder for the IRSs to track the aircrafts position unless you hit the waypoints.

 

Hitting waypoints doesn't actually affect the accuracy. In fact, if you're choosing VORs for DME/DME updating (not required in most modern aircraft), it's preferred that you use off-track VORs. You're correct that the lack of radio-based navaids compromises the position accuracy in theory, but with GPS, it doesn't matter very much. It's not until you get closer to the poles and you kick over to full inertial nav, and by then, radio-based navaids are generally not available either.

Kyle Rodgers

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Kyle, agree on the off track VOR cross referencing.

 

On the waypoints, if I fly PAJN-KSEA, and fly direct after takeoff to LVD, the airplane will waver left and right of track,

 

If I hit the departure waypoints, it does not do that, it flies precise.

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I made a roundtrip flight from PANC to PAFA last night and thought about this thread. I aligned the IRU's in the preflight which took all of 14 minutes, then took off from 7R and left turn direct CAWIN. The NGX had a very tough time tracking in LNAV and I had to fly the leg with HDG SEL.

On the return flight, using the PUYVO1 departure to PUYVO, touching the waypoints, the airplane navigated with no problem to the KROTO2 arrival procedure.

This doesn't only happen in Alaska, if I fly in Central Anerica taking off from MHTG for example and flying direct to AUR the same thing happens.

If a departure procedure is used with nearby waypoints and those are checked in, the airplane tracks correctly.

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