P3D V 4.4     Since release  of 757 in december and 3 times new install I try to find the correct way to make a descent using VNAV and autoland.

I have tried several different airports and distances altitudes.

Studied the manuales and looking at many good ideas in forum and YOUTUBE, but I allways end up with a diving aircraft and very high speed.

All relevant data in the FMC  but I do something wrong.

Climb OK  and CRZ OK.  Before T/D I set altitude to ZERO (also tried fx. 2000.  When FMC in page VNAV reach T/D the aircraft descent maybe VS 4000  and accel..
OK I can use FLC and back to VNAV and control speed manual-


I used the 777 in earlier version P3D and had no problems.
I also use the AIRBUS PRO - and are aware that I cannt compare the two aircrafts behavior.


Hope someone can give an idea.

Hi,

do you mean an automatic landing or a landing with VNAV? Autoland requires some ILS with LOC and GS signal in addition to some other technical requirements for the 757. VNAV is only eligible for an NPA (LOC, VOR, NDB) if conditions permit. VNAV can not remain active until touchdown and can not be used in connection with an automatic landing

Thank you for the reply.
I thought the VNAV button had to be active when the FMC Vnav page "give" the descent order.
Fine suggestion.  I´ll turn off the Vnav button.

For an FMS-based approach using LNAV and VNAV, the data is already relevant there. But there are different ways to fly an approach. ILS, LOC, RNAV, VOR, NDB. ILS uses signals from ground transmitters, which guide the aircraft laterally and vertically when APPR mode is activated. Will or may one use only the signal of the LOC, only the mode LOC is activated. VOR and NDB Approaches can be flown using RAW data (reception of the NDB or VOR), but the autopilot can not take off signals automatically, so you have to control via HDG (or by hand). Also there is no vertical guidance here, but one must sink again, this time however also with the help of the autopilot (VS). In today's times, however, for these approaches, as well as for the RNAV approaches, the data in the FMS can be used to ultimately fly to check all data using LNAV and VNAV (in VOR and NDB but in parallel under control of RAW data). In some aircraft, the LNAV and VNAV modes are also flyable as an IAN as an ILS approach. But the 757 does not offer that. On the approach using LOC, ILS, LNAV and VNAV, one approaches the IF on a fixed routing or vectoring, then activates LOC, APPR or LNAV. When APPR is then automatically captured the GS, at LOC, VOR, NDB or RNAV, the descent is then started by means of VS or just VNAV (previously adjust the height accordingly and check the data on the LEGS side). That's a quick answer

Thank you FraPre for a wake up call...

There sure is a lot to learn. 
I have now  made 2 "happy" landings.
Before T/D I set a new altitude ZERO and    kept VNAV button activated during descent.
When close to the airport I went for LOC  and  airport  within 10 nm  I pushed  APPR.
During one descent I used the speedbrake - perhaps 15 sec. to prevent overspeed.

In the other test I changed data for a waypoint that was 331/12300  to 280/12300

VNAV was turned of autom..

Maybe I have have been totally wrong - but it turned OK for me.

Thank you

The altitude is set before the descend to the altitude in the MCP for which the ATC clearance was made. In offline mode you can set the height, which stands on the charts at the FAF / FAP. Here begins the final approach, for a VNAV controlled approach then before, inbound to the FAF / FAP set the DA, for an ILS controlled approach one need not set a lower altitude, as one of the active GS mode quasi independently descendants. Here then in the course of the final approach, the height is set for the missed approach, with some airlines really set 00000, but this is a company procedure. But nice that it works now at least.

I never set the altitude to 0000, but I often set the altitude to a low altitude, usually around 2000ft (this is often done just after the Pause at Top of Descent, which I have turned on), and once I capture the ILS/GS, I press APP button on the MCP, and once the autoland is established, I reset the altitude to the missed approach altitude.

I´ll try to set the altitude = the last waypoint  like I do using the Majestic Q400.

Correct It seems unreal to set  ZERO - but.

Also I set the stability a little bit higher ( nose up) than calculated.
Last test no need for speedbrake.

Thank for for the advice.  Nice to be on the right track...

Enclosed a photo  - OK landing - beautiful repaint . thank you

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Markoz wrote on Jan 28^th, 2019 at 3:30pm:

I never set the altitude to 0000, but I often set the altitude to a low altitude, usually around 2000ft (this is often done just after the Pause at Top of Descent, which I have turned on), and once I capture the ILS/GS, I press APP button on the MCP, and once the autoland is established, I reset the altitude to the missed approach altitude.

Precisely the way I saw the Captain of the Airtours(now defunct) 757-200 make the Approach Landing into Dalaman on a fantastic  ITVV video last night.

I have this problem too, VNAV is totally messed up, has been for a while now. It just descends at crazy rates, 4000ft+. It also fails to obey speed restrictions below 10,000.