Gotcha.  Yeah that's a strange one, I'll check it out.

8 hours ago, Michael Moe said:

Thanks , sorry yes no VNAV APP offcause.It wad just to illustrate the 3degree GP at 2450 feet. VNAV Speed was  staying in that mode despite flaps extending and landing gear.

Michael Moe

I have seen the same thing in two flights at least, and I bought the IFly B738 max 2 days ago. I thought I was setting the flaps in the wrong moment. I'll test it more.

 

11 hours ago, Stearmandriver said:

Can't say I've noticed and I've been testing the Max quite a bit, so I guess that means it's within the range of normal.  It is correct that the TOC and green banana won't perfectly agree and will change during climb as conditions change.  If you see them agree perfectly and never change in other sim aircraft, then that's not realistic. 

I would suspect that even more than winds, temperature plays a part.  MSFS live weather has a tendency to produce some very goofy temperature shifts.  You could try setting manual weather with a constant temperature layer and see what happens.

Please, I'd be grateful if you can test this on your side, because I don't see any temps or winds shifts, it's just raising its V/S without an apparent reason in the range of 30000+ altitude for about 4000ft.

My opinion on the B738 max at the moment is that it is a very good airplane but I felt better with the PMDG regarding the flight model, but I need to test more the Ifly.

On 3/6/2025 at 5:22 AM, Michael Moe said:

Anyone fresh for a try?

Airport YBCS

STAR NONUM 4Z

LNAV/VNAV RNP Y RWY15

Not once have i had the Max do the VNAV part despite having FMA LNAV/VNAV APP indicated with distance indicating.

My VNAV stays in VNAV Speed and never leaves this mode which must be the problem

I Reduce set speed to 180 prior to CNSI at 4000 feet setting the MCP to 2500 feet but  instead of respecting speed and descend  VNAV PATH never enables and the aircraft stays at 4000 feet.

VNAV should start descend on profile with selected speed.

i have also had this experience as well. 

Is there a new patch out or coming soon?

On 3/5/2025 at 11:22 AM, Michael Moe said:

Anyone fresh for a try?

Airport YBCS

STAR NONUM 4Z

LNAV/VNAV RNP Y RWY15

Not once have i had the Max do the VNAV part despite having FMA LNAV/VNAV APP indicated with distance indicating.

My VNAV stays in VNAV Speed and never leaves this mode which must be the problem

I Reduce set speed to 180 prior to CNSI at 4000 feet setting the MCP to 2500 feet but  instead of respecting speed and descend  VNAV PATH never enables and the aircraft stays at 4000 feet.

VNAV should start descend on profile with selected speed.

This is the first RNP LNAV/VNAV i havent manage in the Max.

This is before the latest bugfix though

VNAV GP is "captured 3 degree" at 2450 feet at CNSNF btw. Normally i would put 900 feet just prior  this FAF  and missed approach altitude 5200 feet at about 2000 feet

Thanks

Michael Moe

I flew this approach tonight and it worked well for me.  Only thing that might strike some as strange is that the MAP is the fix prior to the runway, and the 3 degree glidepath is only built to this fix; you're visual after that.  But LNAV / VNAV worked and speed intervention worked correctly; the plane stayed in VNAV PTH with the speed window open and flaps extended.  You can see it here, for the next week or two or however long Twitch leaves these up.  Never mind the random chatter; several of us were just killing time haha.

https://www.twitch.tv/stearmandriver/v/2399286093?sr=a&t=7712s

Now, I'm using a beta build of the upcoming 1.0.3 update, and I do think there are LNAV and VNAV tweaks that aren't in the public build, so it could very well be that you have a bug that I do not.  Good news is, I get the sense that everyone should have this version in the near future.

Edited March 7, 20251 yr by Stearmandriver

2 hours ago, Stearmandriver said:

I flew this approach tonight and it worked well for me.  Only thing that might strike some as strange is that the MAP is the fix prior to the runway, and the 3 degree glidepath is only built to this fix; you're visual after that.  But LNAV / VNAV worked and speed intervention worked correctly; the plane stayed in VNAV PTH with the speed window open and flaps extended.  You can see it here, for the next week or two or however long Twitch leaves these up.  Never mind the random chatter; several of us were just killing time haha.

https://www.twitch.tv/stearmandriver/v/2399286093?sr=a&t=7712s

Now, I'm using a beta build of the upcoming 1.0.3 update, and I do think there are LNAV and VNAV tweaks that aren't in the public build, so it could very well be that you have a bug that I do not.  Good news is, I get the sense that everyone should have this version in the near future.

Hi Andrew  , Thanks but idid the NONUM4Z coming from PULAX which is straight to CNSNI . Your seem to come from north

But i have done this 3 times now and maybe thought i had a Throttle input (disabled all offcause anyway during A/P)

Looking forward to this 1.03 🙂

Thanks

Michael Moe

 

Edited March 7, 20251 yr by Michael Moe

7 hours ago, Michael Moe said:

Hi Andrew  , Thanks but idid the NONUM4Z coming from PULAX which is straight to CNSNI . Your seem to come from north

But i have done this 3 times now and maybe thought i had a Throttle input (disabled all offcause anyway during A/P)

Looking forward to this 1.03 🙂

Thanks

Michael Moe

 

Transition won't matter if the issue is on the approach.  There's only one procedure coded in the navdata from the IF on in, so behavior won't change depending on where you came from.  

@Stearmandriver in this video at 1h 16min you can see the problem I tried to describe regarding the supposed not normal V/S acceleration near TOC:

 

4 hours ago, Claudius_ said:

@Stearmandriver in this video at 1h 16min you can see the problem I tried to describe regarding the supposed not normal V/S acceleration near TOC:

 

I'll be honest, with all the goofy overlays and popups occurring on this video, I'm not sure if I'm missing something or what... But that looked like a normal level off to me?  What were you expecting to see?

4 hours ago, Stearmandriver said:

I'll be honest, with all the goofy overlays and popups occurring on this video, I'm not sure if I'm missing something or what... But that looked like a normal level off to me?  What were you expecting to see?

It is not so difficult to see just a pair of minutes in that video where you can observe the v\s variations. Anyway, the Ifly support on discord hadn't no difficulty with this video and they told me that it was the Mach transition to cause the strange v\s behavior in proximity of TOC. It's no 100% a good explanation to me, but it's reasonable.

59 minutes ago, Claudius_ said:

It is not so difficult to see just a pair of minutes in that video where you can observe the v\s variations. Anyway, the Ifly support on discord hadn't no difficulty with this video and they told me that it was the Mach transition to cause the strange v\s behavior in proximity of TOC. It's no 100% a good explanation to me, but it's reasonable.

Bearing in mind hes a 737 pilot who I believe helps ifly he knows what hes looking at.

5 hours ago, Claudius_ said:

It is not so difficult to see just a pair of minutes in that video where you can observe the v\s variations. Anyway, the Ifly support on discord hadn't no difficulty with this video and they told me that it was the Mach transition to cause the strange v\s behavior in proximity of TOC. It's no 100% a good explanation to me, but it's reasonable.

Ok, so you're seeing an increase in climb rate at the transition from indicated to mach?  Yes that makes sense then, nothing wrong there.

2 hours ago, Stearmandriver said:

Ok, so you're seeing an increase in climb rate at the transition from indicated to mach?  Yes that makes sense then, nothing wrong there.

You can see that with your eyes on the video I proposed in my previous post. It doesn't make sense looking for something necessarily wrong or not there, but the flight simulation is useful to understand things. So, why the other study level airplanes don't show the same behavior? In decades I'm on civilian flight simulators I've never seen a similar thing, and I was thinking that the liners aren't able to accelerate in such way from 9k ft/min to about 1.5k ft/min when close to their service ceilings. It could be interesting to verify how the real liners behave.

Someone here mentioned RNP approaches.

On a flight from KSAN (San Diego - Runway 27 and SIDS BRDR7) to KPSP (Palm Springs ) and using the PMDG 737 and the (RNP)Y RWY 31L approach to KPSP it seems that I have to handfly the aircraft from the TRM initial approach fix otherwise I end up missing the runway. I'm either too high or too fast. And, I don't understand why the altitude constraint at the PGY waypoint goes all the way up to FL190 (save fuel?) when the MSA at KPSP is only at 12,700 ft. I don't think there are any obstacles requiring FL190 along the flight. A few questions: 

1. Are there any differences between iFly 737 Max8 and PMDG's 737-800 implementation of RNP-AR and missed approaches?  
2. Is there an autoland or autopilot mode for the RNP approach in both iFly and PMDG versions? 
3. How do I know if I am at the RNP approach? Is the FMA supposed to be what is shown in the picture below for the RNP approach?
4. How are missed approaches initiated? Do I press the TOGA switch again or are missed approaches completely handflown? Can I use an auto-pilot for missed approaches?
5. When doing an RNP-AR approach does that literally mean that the flight has to be formally authorized each time or simply that the aircraft has to be certified to fly the approach? In the first case, how is authorization obtained?

EDIT: 
I understand RNP approaches are supposed to be complicated. That probably applies to the BALDI IAF which I assume has CUPOL in its waypoint (Do I have this right? --see chart below - kinda weird why BALDI is even an IAF considering there are other IAF to KPSP). I can understand why BALDI is an RNP approach. It does look difficult. But, the TRM approach doesn't look that complicated at all. Why does TRM require an RNP approach? What does THERMAL mean?

 

 

Flight route. FL190 starting at waypoint PGY. Why?

Edited March 9, 20251 yr by anavsun

11 hours ago, Claudius_ said:

You can see that with your eyes on the video I proposed in my previous post. It doesn't make sense looking for something necessarily wrong or not there, but the flight simulation is useful to understand things. So, why the other study level airplanes don't show the same behavior? In decades I'm on civilian flight simulators I've never seen a similar thing, and I was thinking that the liners aren't able to accelerate in such way from 9k ft/min to about 1.5k ft/min when close to their service ceilings. It could be interesting to verify how the real liners behave.

I guess I'm still not understanding something.  Are you asking why climb rate increases when the transition occurs from indicated to mach?  Because the speed of sound decreases with altitude, so latching on to a mach number during climb means you're climbing more steeply than you were when you were holding a constant indicated speed. 

I'm not sure why you mention 9k ft/ min as that certainly wouldn't be normal, but I didn't see anything like that in your video near the time stamp you referenced.  I saw maybe 1,500ft / min, which is reasonable.  I can definitely verify this is how 737s (and really any jet) flies.  I do believe other sim add-ons do this; if you're using one that doesn't, it's simply not correct.

Don't worry about that, Ifly support understood my observations and they gave good replies.