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Ray Proudfoot

Vertx Diamond DA-62 and holding altitude issue

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I'm having a problem with the DA62 not holding altitude. I can't fathom out why it will climb to FL140 and remain there for quite a while before descending a couple of hundred feet for no apparent reason. See attached screenshot showing commanded altitude is 14,000 but it's dropped to 13,800ft. Am I alone in having this problem in P3D v4.5?

VNAV was engaged but the ToD point is a long way off.

DA62_Altitude.jpg


Ray (Cheshire, England).
System: P3D v5.3HF2, Intel i9-13900K, MSI 4090 GAMING X TRIO 24G, Crucial T700 4Tb M.2 SSD, Asus ROG Maximus Z790 Hero, 32Gb Corsair Vengeance DDR5 6000Mhz RAM, Win 11 Pro 64-bit, BenQ PD3200U 32” UHD monitor, Fulcrum One yoke.
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Hi Ray, the altitude is correct as shown in green 13800' , I think when you engage vnav the the decent altitude ( on the tape} is shown in amber ready for you to enter.

Edited by onebob

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Check the waypoint altitudes along your flightplan route in the MFD to make sure they are entered to the TOD point. If they arent entered and you have engaged VNAV (as you would in an FMC) the airplane will start a shallow descent at a calculated distance to make the arrival airport elevation. You can program VNAV in the MFD to make it work the way you intend for it to.  Also in the G1000 you should get an aural alert when you are approaching TOD I normally use that as a trigger to engage VNAV if I want to descend that way.  These guys have a nice series on the G1000.  I've used it to compare the the features of the actual unit to the one offered in the Vertx

 

Edited by jalbino59

Jose A.

Core Components: AMD Ryzen7 7700X - G.Skill FlareX 32 GB DDR5 6000 CL36 (XMP)  - Gigabyte B650M Aorus Elite AX  - Asus ROG Strix RTX3060 12gb

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29 minutes ago, onebob said:

Hi Ray, the altitude is correct as shown in green 13800' , I think when you engage vnav the the decent altitude ( on the tape} is shown in amber ready for you to enter.

Hi Bob. Sorry, I don’t quite follow what your saying. The commanded altitude is shown in yellow - 14000ft. I have entered a couple of altitude restrictions in the plan but the ToD point to meet those is a long way off.

26 minutes ago, jalbino59 said:

Check the waypoint altitudes along your flightplan route in the MFD to make sure they are entered to the TOD point. If they arent entered and you have engaged VNAV (as you would in an FMC) the airplane will start a shallow descent at a calculated distance to make the arrival airport elevation. You can program VNAV in the MFD to make it work the way you intend for it to.  Also in the G1000 you should get an aural alert when you are approaching TOD I normally use that as a trigger to engage VNAV if I want to descend that way.  These guys have a nice series on the G1000.  I've used it to compare the the features of the actual unit to the one offered in the Vertx

Jose, I have entered a couple of altitude constraints for waypoints on the STAR but not for any at cruise. Is that necessary to keep the aircraft at its commanded altitude? If so, I’ll do that for the last waypoint before ToD. Or would you advise not to engage VNAV until close to ToD?

Yes, I’m hearing the aural alert when ToD is 1 minute away. So that aspect seems okay. It’s frustrating because the docs just point to the real G1000 manual but there isn’t a tutorial on setting altitudes for the plan. Surely it’s not necessary to set an altitude for each one.

The other annoyance is the altitude constraints are deleted when selecting a Direct To. I’ll watch that video, thanks. 👍


Ray (Cheshire, England).
System: P3D v5.3HF2, Intel i9-13900K, MSI 4090 GAMING X TRIO 24G, Crucial T700 4Tb M.2 SSD, Asus ROG Maximus Z790 Hero, 32Gb Corsair Vengeance DDR5 6000Mhz RAM, Win 11 Pro 64-bit, BenQ PD3200U 32” UHD monitor, Fulcrum One yoke.
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1 hour ago, Ray Proudfoot said:

Or would you advise not to engage VNAV until close to ToD?

That is how I prefer to do it.  You could also program a descent to any particular waypoint in the MFD undder "Flight Plan>VNAV Profile" section to use a flight path angle of say 2.5 degrees, or descent rate (ie -1500 FPM) and the plane should hold your selected altitude until it can it can descend at the rate or angle you've selected

 

1 hour ago, Ray Proudfoot said:

It’s frustrating because the docs just point to the real G1000 manual but there isn’t a tutorial on setting altitudes for the plan.

Yes, it seems due to the circumstances, we have to rely on peer to peer to help us understand this title, but that video series I suggested should help, I believe one episodes covers VNAV exclusively.

1 hour ago, Ray Proudfoot said:

Surely it’s not necessary to set an altitude for each one

No it isn't but if you are going to engage VNAV well in advance only programing the altitude constraints and not the VS or FPA then the aircraft will try to meet the constraint at a default 100-200 fpm descent rate. So once you reach cruise, flip over to the MFD flight plan page and look at the VNAV profile section.  Change the FPA or VS to your preferred rate and the G1000 should recalculate the TOD for you.     

Edited by jalbino59
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Jose A.

Core Components: AMD Ryzen7 7700X - G.Skill FlareX 32 GB DDR5 6000 CL36 (XMP)  - Gigabyte B650M Aorus Elite AX  - Asus ROG Strix RTX3060 12gb

Storage: WD Black SN750 NVMe 1TB - AData sx8200 Pro NVMe 1TB - Samsung 860 EVO 500GB - Samsung 870 EVO 1TB

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Hi Jose. That’s the first thing I’ll do then. Refrain from engaging VNAV until I’m a few minutes away from ToD. If that cures the drift downwards that’s a good start.

I’ll keep to altitude constraints as they can be seen on the Approach charts. I can try being more adventurous with experience.

The video you linked to was helpful, thanks. Ideally I’d want to watch it when in the DA62 cockpit so I can replicate the actions. I can handle navigation in the 737 as well as Concorde so with some time the DA62 should be mastered. Helps keep the brain cells going! 😁

Thanks, you’ve been very helpful. 👍


Ray (Cheshire, England).
System: P3D v5.3HF2, Intel i9-13900K, MSI 4090 GAMING X TRIO 24G, Crucial T700 4Tb M.2 SSD, Asus ROG Maximus Z790 Hero, 32Gb Corsair Vengeance DDR5 6000Mhz RAM, Win 11 Pro 64-bit, BenQ PD3200U 32” UHD monitor, Fulcrum One yoke.
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Your welcome Ray, enjoy and please stay healthy.  

 

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Jose A.

Core Components: AMD Ryzen7 7700X - G.Skill FlareX 32 GB DDR5 6000 CL36 (XMP)  - Gigabyte B650M Aorus Elite AX  - Asus ROG Strix RTX3060 12gb

Storage: WD Black SN750 NVMe 1TB - AData sx8200 Pro NVMe 1TB - Samsung 860 EVO 500GB - Samsung 870 EVO 1TB

WIN10 - P3D v.5.3 HF2 - XPLANE 11 - MSFS

 

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Ray, this might seem to be a dumb question (I'm surprisingly good at those :biggrin:), especially seeing as you have a link to your local weather station in your sig, but will a change in pressure during your flight not affect the displayed altitude if you do not reset the altimeter? Does the new sim use and understand different transition altitudes or does it act like "you're not at 18000 so standard pressure doesn't apply?"


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7 hours ago, HighBypass said:

Ray, this might seem to be a dumb question (I'm surprisingly good at those :biggrin:), especially seeing as you have a link to your local weather station in your sig, but will a change in pressure during your flight not affect the displayed altitude if you do not reset the altimeter? Does the new sim use and understand different transition altitudes or does it act like "you're not at 18000 so standard pressure doesn't apply?"

Hi Mark. I do reset the altimeter as I pass through the transition altitude. With a cruise level of FL140 / 14,000ft that won't apply for US flights but does for European ones. I don't see any pressure changes being responsible given the small but consistent deviation in altitude. It's around -200ft, never more, never less.

But whilst I'm on the Vertx Diamond DA62 and I'm throwing this out to all users - why is it such a difficult aircraft to taxi? It needs a lot of power to get it moving but unless you then reduce the throttle to near zero it's up to 20kts in no time. A total nightmare. Is the real aircraft as difficult to taxi?

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Ray (Cheshire, England).
System: P3D v5.3HF2, Intel i9-13900K, MSI 4090 GAMING X TRIO 24G, Crucial T700 4Tb M.2 SSD, Asus ROG Maximus Z790 Hero, 32Gb Corsair Vengeance DDR5 6000Mhz RAM, Win 11 Pro 64-bit, BenQ PD3200U 32” UHD monitor, Fulcrum One yoke.
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18 hours ago, Ray Proudfoot said:

Hi Bob. Sorry, I don’t quite follow what your saying. The commanded altitude is shown in yellow

Hi Ray, sorry I didn't get back but i was doing a test flight last evening and was unable to complete it, will try again, however I think you may have to set the decent altitude before setting up the vpath and of course click the vnav button before TOD. In you photo you are  at altitude 13800 and the decent alt set at 14000 and possible why that is showing as a warning in yellow.

bob

Edited by onebob

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2 hours ago, Ray Proudfoot said:

But whilst I'm on the Vertx Diamond DA62 and I'm throwing this out to all users - why is it such a difficult aircraft to taxi? It needs a lot of power to get it moving but unless you then reduce the throttle to near zero it's up to 20kts in no time. A total nightmare. Is the real aircraft as difficult to taxi?

I've never flown Diamond but since they provided a link to the real POH and I recall reading in it that depending on load, the DA62 needs about 45 to 55 percent power to break away and about 15 to 17 to keep moving.  Since the plane is almost completely carbon fiber it makes sense it would taxi differently than an AC with a metal airframe because of the lower weight, and It would seem developer tried to model that.  But most developers agree P3D's ground friction variables are hard to work with.  If you have fairly accurate throttle hardware it becomes a little easier to get used to over time


Jose A.

Core Components: AMD Ryzen7 7700X - G.Skill FlareX 32 GB DDR5 6000 CL36 (XMP)  - Gigabyte B650M Aorus Elite AX  - Asus ROG Strix RTX3060 12gb

Storage: WD Black SN750 NVMe 1TB - AData sx8200 Pro NVMe 1TB - Samsung 860 EVO 500GB - Samsung 870 EVO 1TB

WIN10 - P3D v.5.3 HF2 - XPLANE 11 - MSFS

 

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1 hour ago, onebob said:

Hi Ray, sorry I didn't get back but i was doing a test flight last evening and was unable to complete it, will try again, however I think you may have to set the decent altitude before setting up the vpath and of course click the vnav button before TOD. In you photo you are  at altitude 13800 and the decent alt set at 14000 and possible why that is showing as a warning in yellow.

bob

Hi Bob,

See the attached screenshots for a flight from MIlan down to Nice. Cruise Alt is FL130 / 13,000ft. You'll notice on the right hand display I have engaged VNAV otherwise I'd never know where the ToD was. Notice the altitude constraint of 4,000ft for the approach fix.

On the left display I did not engage VNAV but with still 20mins before ToD to go the aircraft slowly started to descend. I stopped it at 12,800ft and engaged VSPD to climb back up to FL130.

Why it does this is totally inexpicable. It seems it's deciding a shallow descent is required to meet a non-mandatory altitude fix of 12,900ft at BORDI. These shots were taken well before the descent started.

I think I'll assign a constraint of the cruise level for the last waypoint before ToD (BORDI). I think that will ensure the aircraft doesn't start a drift downwards.

G1000_PFD.thumb.jpg.70d47f49148548b315a426c73f7269b0.jpg

 

G1000_Map.thumb.jpg.926bc755bff75c7162ec234f0190e728.jpg

Is this how you handle your descents?

Jose, thanks for the explanation of the taxi situation. I suppose the developer can only work with what's available to him in P3D and if there are restrictions the problem lies with L-M. Maybe one day they'll improve these things but I won't hold my breath!


Ray (Cheshire, England).
System: P3D v5.3HF2, Intel i9-13900K, MSI 4090 GAMING X TRIO 24G, Crucial T700 4Tb M.2 SSD, Asus ROG Maximus Z790 Hero, 32Gb Corsair Vengeance DDR5 6000Mhz RAM, Win 11 Pro 64-bit, BenQ PD3200U 32” UHD monitor, Fulcrum One yoke.
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31 minutes ago, Ray Proudfoot said:

Is this how you handle your descents?

If you notice on your 2nd screenshoot the ACTIVE VNAV WPT is 4000 at D207X.  The sink rate being used to meet that waypoint is -570 FPM.  Using that sink rate the airplane has to start down before BORDI and cross BORDI at 12,900, PIGOS at 7600 to ultimately meet the 4000ft constraint at D207X. Again this is all calculated at a sink rate of -570 FPM

If you change the VS TGT to a more realistic say -1500 FPM the G1000 should recalculate the TOD for you, it will also change the waypoint altitudes along the way to back your selected cruise altitutude in the PFD (BTW, thats also the reason for the climb back to cruise alt when you engaged VNAV SPD) and begin the descent further down the route when it intersects the point where a 1500 FPM descent is required to meet the same ACTIVE VNAV WPT constraint. 

Edited by jalbino59

Jose A.

Core Components: AMD Ryzen7 7700X - G.Skill FlareX 32 GB DDR5 6000 CL36 (XMP)  - Gigabyte B650M Aorus Elite AX  - Asus ROG Strix RTX3060 12gb

Storage: WD Black SN750 NVMe 1TB - AData sx8200 Pro NVMe 1TB - Samsung 860 EVO 500GB - Samsung 870 EVO 1TB

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Hi Jose,

I did as you suggested and set a descent rate of 1500fpm. This is on the return flight from Nice back to Milan.

I set a constraint of 13,000ft (my cruise alt) for the last waypoint before ToD. I then set another of 4,000ft for the FAF 35L.

But on reaching ToD the descent rate changed to 800fpm. I can only think a higher rate wasn't needed to achieve 4000ft at the FAF.

The aircraft still descended 100ft well before ToD. No further, just 100ft. Very strange. Here's the state of play. Can you see any reason why it would do that?

 

DA62_DescentTooEarly.jpg


Ray (Cheshire, England).
System: P3D v5.3HF2, Intel i9-13900K, MSI 4090 GAMING X TRIO 24G, Crucial T700 4Tb M.2 SSD, Asus ROG Maximus Z790 Hero, 32Gb Corsair Vengeance DDR5 6000Mhz RAM, Win 11 Pro 64-bit, BenQ PD3200U 32” UHD monitor, Fulcrum One yoke.
Cheadle Hulme Weather

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2 hours ago, Ray Proudfoot said:

The aircraft still descended 100ft well before ToD. No further, just 100ft. Very strange. Here's the state of play. Can you see any reason why it would do that?

 

Strange indeed, if you fly this route again try just entering the constraints for the arrival, don't enter any cruise restraints. When you reach cruise altitude change VS TGT to -900 FPM and then select VNAV. (VS TGT is just a target once the plane reaches the TOD the VS REQ will show you the actual decent rate required to meet the constraint based on your speed over the ground.)  

The seemingly arbitrary 100ft altitude drop is strange indeed. I see the VPTH in white on the PFD which means VNAV is armed but not active (it annunciates green when it's active) do you recall clicking VNV again after changing the VNAV profile?  (Like clicking EXEC on an FMS airplane)

If you like please feel free to post or send me your flight plan and I'll let you know how it works for me.

Edited by jalbino59

Jose A.

Core Components: AMD Ryzen7 7700X - G.Skill FlareX 32 GB DDR5 6000 CL36 (XMP)  - Gigabyte B650M Aorus Elite AX  - Asus ROG Strix RTX3060 12gb

Storage: WD Black SN750 NVMe 1TB - AData sx8200 Pro NVMe 1TB - Samsung 860 EVO 500GB - Samsung 870 EVO 1TB

WIN10 - P3D v.5.3 HF2 - XPLANE 11 - MSFS

 

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