Recently we have seen a lot of codes used to unlock our products being offered for discounted prices. Almost all of them are bought using stolen credit cards. These codes will all be blocked by our systems and you will have to try to get your money back from the seller, we are unable to assist in these matters. Do be very careful when you see a deal that is almost too good to be true, it probably is too good to be true.

Jump to content

Archived

This topic is now archived and is closed to further replies.

Dakota558

NAV mode not very accurate

Recommended Posts

After a couple of flights, I have noticed that the AP is struggling to track the FMS course in NAV mode (yes, NAV source is set to FMS1). For each waypoint, the aircraft first turns      opposite, and after that will turn left and right of track until eventually coming on track. It´s almost like it´s tracking VOR stations and is struggling when coming closer to each station. It does remind me of the KAP 140 auto pilot which does a rather terrible job of maintaining course, both VOR and GPS...

 

I can't see anyone else commenting on this, so there is a possibility that I'm doing something wrong here. 

I´m using Prepar3D v4 with AS2016.

 

Instead of posting another topic, here is another question: Is there any tables which gives you the required N1 setting for cruise? I could not find anything in the manuals.

 

Share this post


Link to post

Try using direct to [your next waypoint]. 

For example if i delete a waypoint in my FMC, the CRJ wont fly to the next waypoint after the deleted one, so I have to manually set a direct to the one after the deleted one.

At least that worked for me...

Oh, yea and also the NAV disengages sometimes, so if anything is suspicious, check if your NAV switch is on.

Share this post


Link to post

Required N1 setting is whatever is needed for you to keep your desired speed. There is no fixed table as this differs with conditions. On the real plane, pulling the thrust levers back to get a fuel flow of about 750-800kg/h per engine wil generally result in about M.77 but again, dependent on conditions and requires adjustments from you as pilot since you are effectively the autothrottle/thrust.

Share this post


Link to post
22 minutes ago, swaor said:

For example if i delete a waypoint in my FMC, the CRJ wont fly to the next waypoint after the deleted one, so I have to manually set a direct to the one after the deleted one.

That's exactly how it is done. If you just remove a waypoint, there's no automatic sequencing.

Share this post


Link to post
2 hours ago, swaor said:

Oh, yea and also the NAV disengages sometimes

 

CRJ Pilots on the team have told us this happens in the actual aircraft as well.  I don't think it was planned to be like that, just pointing out a coincidence!

 

Share this post


Link to post
gerade, DaveCT2003 sagte:

 

CRJ Pilots on the team have told us this happens in the actual aircraft as well.  I don't think it was planned to be like that, just pointing out a coincidence!

 

Good to know :)

Share this post


Link to post

I have found my N1 in cruise is generally around 80.4 for Mach .74, and a bit higher for Mach .78 It depends on weight and OAT, but those figures are pretty close.

Share this post


Link to post

I'm having a similar issue with the NAV autopilot setting, both in terms of the mode shutting off without warning and not tracking properly.  My aircraft keeps trying to turn about 30 degrees left of the proper route when nav is engaged.

 

Other than that however I'm having a lot of fun on my first flight.

Share this post


Link to post

Had the same issue trying to fly the RNAV-Z into KSAN, the NAV did not want to track the downwind to final turn and I ended up shooting pretty well past the final approach course

Share this post


Link to post

Same thing here, happened every flight so far.. Tried the RNAV runway 19 at KDCA and it was all over the place..

Untitled.jpg

Share this post


Link to post
11 hours ago, Navigation said:

Again the aircraft is a challenge and fun. Time to use your pilot skills lol

 

I highly doubt an aircraft manufacturer would build an aircraft that wouldn't track the flight plan accurately, you'd have atc yelling at you constantly..

Share this post


Link to post

I used direct to DBL in Aspen, few minutes later.. Something going on with ND for sure..

Untitled.jpg

Share this post


Link to post
13 minutes ago, tyacono said:

I highly doubt an aircraft manufacturer would build an aircraft that wouldn't track the flight plan accurately, you'd have atc yelling at you constantly..

 

I can see why one might believe this, but actually it's not really true.

 

FMS on all sorts of real aircraft burp and hiccup from time to time, routes on Nav Displays (MFDs) get drawn in funky ways and the FMS gets confused by them and sometimes just decides to fly straight with or without a nav mode disconnect, etc.  This is one of the many reasons we have trained pilots aboard, and pilots are trained to perform continual scans all of their instruments and monitor aircraft performance and how the autopilot is functioning.  I was taught that when on Auto Pilot, the PF would say "Scheduled Left" when the Auto Pilot made a left turn in accordance with the programmed route, signifying not only that the turn was in accordance with the flight plan, but the PF was closely monitoring the flight plan and aircraft/Auto Pilot compliance.  If you watch enough Youtube videos of flight crews you'll see/hear this done.

 

My very best wishes.

 

Share this post


Link to post
7 minutes ago, DaveCT2003 said:

 

I can see why one might believe this, but actually it's not really true.

 

FMS on all sorts of real aircraft burp and hiccup from time to time, routes on Nav Displays (MFDs) get drawn in funky ways and the FMS gets confused by them and sometimes just decides to fly straight with or without a nav mode disconnect, etc.  This is one of the many reasons we have trained pilots aboard, and pilots are trained to perform continual scans all of their instruments and monitor aircraft performance and how the autopilot is functioning.  I was taught that when on Auto Pilot, the PF would say "Scheduled Left" when the Auto Pilot made a left turn in accordance with the programmed route, signifying not only that the turn was in accordance with the flight plan, but the PF was closely monitoring the flight plan and aircraft/Auto Pilot compliance.  If you watch enough Youtube videos of flight crews you'll see/hear this done.

 

My very best wishes.

 

Look at the above pic I just posted, highly doubt that should happen.

Share this post


Link to post

Im no expert. But cant it be that this happens bec you are too fast? I didnt do many flights yet, and i also experienced this. But im not really sure if its not me doing something wrong here, because in every case it happened, i was just too fast.

As i see it, the CRJ doesnt follow speed restrictions etc automatically. Where a a320 or 737 would automatically adjust the thrust to let this not happen, here its actually the pilot who has to control exactly this.

But again, im in noway an expert and i only did few flights with the CRJ.

Share this post


Link to post

I just flew the plane adjusting heading manually following the flight path. The nav control is just not doing its job plain and simple 

Share this post


Link to post

no plane follows the flightpath if too fast....every boeing fmc and dash8 and hatever do the same. Try follow a fp in a 737 when speed is set to manual control and your set to 50 kts higher as the fmc calculated. The very same happens. You appear next to the path.

Again, you have to control this here.

Share this post


Link to post
12 minutes ago, Senchay said:

no plane follows the flightpath if too fast....every boeing fmc and dash8 and hatever do the same. Try follow a fp in a 737 when speed is set to manual control and your set to 50 kts higher as the fmc calculated. The very same happens. You appear next to the path.

Again, you have to control this here.

I'm at .74 mach.. How's that too fast for a direct to?

21 minutes ago, Navigation said:

I just flew the plane adjusting heading manually following the flight path. The nav control is just not doing its job plain and simple 

Exactly.

 

Share this post


Link to post
2 hours ago, tyacono said:

Same thing here, happened every flight so far.. Tried the RNAV runway 19 at KDCA and it was all over the place..

Untitled.jpg

 

 

It appears you are tracking to a waypoint over 700 NM from your current position. I believe Hans mentioned that with a leg length that long, that the course line on the ND is going to appear offset because the actual course is a great circle (over the curved earth), while the ND treats the earth as flat for the purpose of displaying waypoints and course lines. I don't know if this is a limitation of the actual aircraft ND, but it may be a limitation in the sim emulation of the ND.

 

I do know that even in the advanced PMDG aircraft I have seen the aircraft flying to one side of the plotted course line on very long (350+ NM) legs between oceanic waypoints.

 

This shouldn't be a major issue on short legs of course, or while flying an RNAV approach, so if you are seeing problems there, something may be "buggish".

 

If you see the aircraft off track, try accessing the NAV STATUS screen on the MFD (press the MFD MENU button on the FMS). I don't know if that page is fully emulated, but it would provide information on the upcoming waypoint related to your current position including: bearing, heading, course, ground track and any cross-track error that may currently exist.

Share this post


Link to post

I also found the aircraft cannot do the RNAV 19 at KDCA. I had to takeover manually as the autopilot took a hard right turn once it "captured" the course. It also appears to have issues drawing the courses. 

2017-8-3_20-55-37-613.png

Share this post


Link to post

I had questions regarding this too.  Attached is my flight to KSEA, and screenshot is taken 180nm SE of SEA.  The aircraft shows its on course from the lines drawn, but off course in the FMS needle.  Also put in a fix for SEA at 100nm out, yet it says im 579nm out. Headwind is right on the nose so its not a course compensation. 

 

 

 

2017-8-4_14-23-19-404.jpg

Share this post


Link to post

I'm afraid there is a general problem concerning the FMS. Try flying RWY 28, SID DEGE2W at LSZH Zurich. Several things happened there. First thing is that the interpretation of the CF leg to KLO is wrong. It should do a left turn ISO what it shows on the ND: a right turn (the shortest way round). You would end up with pretty serious discussions on Zurich ATC when doing this....:D

 

The second thing I saw when flying this departure was that when engaging the A/P during climbout it did not follow the FD command. It started a left trun long before even ZH552 was reached an never rejoined the SID but continued turning left and right inorder to re-catch (at least trying to) the SID. Had I not returned to manual flying and updating the FMS with a DCT-TO towards a reasonable point, I'm sure it would still turn when writing this after half an hour... ;)

 

The A/P not following the FD bars is actually something that should not be possible as the FD bars are representing the steering command for the A/P !

Share this post


Link to post
Guest
This topic is now closed to further replies.

×
×
  • Create New...