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757 Captain III >> 757 Captain III - General >> VNAV descent in the 757 https://www.captainsim.org/forum/csf.pl?num=1559949362 Message started by CaptLE on Jun 7^th, 2019 at 11:16pm

Title: VNAV descent in the 757
Post by CaptLE on Jun 7^th, 2019 at 11:16pm

Just to clarify if other members have experienced these VNAV descent issues:

1) Speed constraints are not adhered to when input into the FMC for a waypoint in the descent phase (Screenshot 1)

2) Selected speed (SEL SPD) in the VNAV descent page does not function; the speed bug on the tape is erroneously increased no matter what input is made (Screenshot 2)

3) Speed restrictions (SPD RESTR) are not followed when the user inputs an entry to the VNAV DES page (Screenshot 3)

These entries appear to work fine during VNAV CLB and CRZ but the DES page is very unpredictable.

Please find the screenshots attached in the following posts:

Title: Re: VNAV descent in the 757
Post by CaptLE on Jun 7^th, 2019 at 11:17pm

VNAV speed constraint of 235 KIAS, bug remains at 250 KIAS:

CS757-_DES_SPEED_CONSTRAINT.jpg ( 111 KB | 134 Downloads )

Title: Re: VNAV descent in the 757
Post by CaptLE on Jun 7^th, 2019 at 11:18pm

A manually selected speed of 240 KIAS in the VNAV DES page sends the speed bug to 402 KIAS:

CS_757-_SEL_SPD_DES.jpg ( 112 KB | 89 Downloads )

Title: Re: VNAV descent in the 757
Post by CaptLE on Jun 7^th, 2019 at 11:20pm

Finally, a SPD RESTR of 230/FL80 is entered. The aircraft is now at 7880ft and the speed bug remains at 235 KIAS:

CS_757-_DES_SPD_RESTR.jpg ( 464 KB | 144 Downloads )

Title: Re: VNAV descent in the 757
Post by JOHN3057 on Jun 23^rd, 2019 at 8:35pm

I have experienced this in my last 3 flights. I don't know who was in charge of testing the last update but it has completely broke this airplane. Prior to this none of these issues were present. A few bugs here and there. But now its as if this add on has taken 5 steps back. Very frustrating for me since it was a joy to fly at one point :o

Title: Re: VNAV descent in the 757
Post by CaptLE on Jun 24^th, 2019 at 11:16am

Hi John,

Thanks for your reply. These screenshots were from update 1.400, but I still had these issues back in 1.303.
In which update did you start noticing it?

I see there is a new 1.404 (for FSX, released yesterday) but I have not yet tested it. Hopefully it will at least fix some of the VNAV issues since I filed some bug reports about it during the 1.400. I'll test it as soon as I can :)

Title: Re: VNAV descent in the 757
Post by CaptLE on Jun 24^th, 2019 at 3:50pm

Just landed a test flight in 1.404 for FSX. No changes to VNAV this time around as far as I can tell. There is no changelog so it wasn't a guaranteed fix anyway. I'll keep testing over the next few days to find more evidence of bugs.

Title: Re: VNAV descent in the 757
Post by Crabby on Jul 9^th, 2019 at 6:13pm

Unfortunately CS has not acknowledged these VNAV issues. I posted pictures too and was "kindly" asked to contribute to another forum including pointing out the exact area in the manual that I "thought" was not being followed.

So I just hangared the airplane and started advising others to not purchase CS products until such time as CS can learn customer support.

Title: Re: VNAV descent in the 757
Post by CaptLE on Jul 10^th, 2019 at 9:26pm

I posted a bug report for the speed restriction issue on descent a short while before the latest update. It was acknowledged and put on the list, so there's possible improvement for that issue in the future.

For the speed constraints, I've found the aircraft to follow on certain occasions and disregard on others, so it's difficult to pinpoint the manual references and describe how it functions for a bug report.
Same for SEL SPD - it sometimes locks to 240kts regardless of input and then for others it rapidly accelerates to 400+kts like in the screenshot; it's hard to summarise in a bug report.

Hopefully the 757 can be refined further in time. The descent phase is really letting it down now. :-/