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757 Captain III >> 757 Captain III - General >> How to use Auto throttle? https://www.captainsim.org/forum/csf.pl?num=1553170872 Message started by andy a on Mar 21^st, 2019 at 12:21pm

Title: How to use Auto throttle?
Post by andy a on Mar 21^st, 2019 at 12:21pm

Hi
I bought the CS 757 III P3D v4( Base pack and Expansion pack) a few weeks ago. Base pack has now been updated to 1.3.0.3.
It's a great aircraft which I enjoy very much. However, although I engage the Auto Throttle switch during taxiing, the speed after take off rises way past the 250kts listed on the FMC Legs Page, when the aircraft is climbing to the Transition Alt of 6000'. I have to manually control the speed via my Saitek Throttle Quadrant, as when left without manual input the speed rises to 300kts.

I have tried using F3 on the keyboard to control the throttle just in case there was some conflict with the Saitek quadrant.
I have also re-installed aircraft in an attempt to resolve the issue.

I have other aircraft where the A/T does not cause this problem, and I would be pleased if someone could offer me some advice.
Regards
Andy

Title: Re: Auto throttle is not controlling speed 757 III P3D
Post by Markoz on Mar 21^st, 2019 at 8:18pm

The way I get the AT to work on/after takeoff, is that I press the EPR once I'm ready to take off, and after takeoff, and I have raised tthe landing gear, and climbed to least 400ft AGL, I press the AP CMD switch, then LNAV & VNAV (LNAV and VNAV can be switched on in any order).

Title: Re: Auto throttle is not controlling speed 757 III P3D
Post by andy a on Mar 22^nd, 2019 at 12:14am

Thank you for your reply Mark.
My procedure is more or less the same as yours. I arm VNAV and LNAV prior to take off and then above 1500', press auto pilot.

I did notice that during climb out the VNAV light went off by itself, and then V/S light came on with window showing 3000fpm climb rate, with the speed increasing.
I haven't noticed this before as I've been too busy watching speed tape. However, when I again pushed the VNAV button it lit, and the V/S light went off...and then the Speed behaved as it should. The rest of the flight was satisfactory.

Hopefully the gremlin has gone ;)
Thank you again.
regards
Andy

Title: Re: Auto throttle is not controlling speed 757 III P3D
Post by Markoz on Mar 22^nd, 2019 at 4:11am

I do it thaat way because I often have the VNAV and LNAV not seeming to be on after I click on the AP switch. I don't think they should do that, so it might be a bug.

Title: Re: Auto throttle is not controlling speed 757 III P3D
Post by trevors on Mar 22^nd, 2019 at 9:57am

Don't engage the AP below 1000' AFE. That's why the MCP is changing from VNAV to VS.

Title: Re: Auto throttle is not controlling speed 757 III P3D
Post by Markoz on Mar 22^nd, 2019 at 1:03pm

trevors wrote on Mar 22^nd, 2019 at 9:57am:

Don't engage the AP below 1000' AFE. That's why the MCP is changing from VNAV to VS.

This happens to me even after I've turned the AP on when above 1000'. I've even tried it at 3000', and it still does this, so I will continue to use the method I described above. ;)

Title: Re: Auto throttle is not controlling speed 757 III P3D
Post by andy a on Mar 22^nd, 2019 at 8:24pm

trevors wrote on Mar 22^nd, 2019 at 9:57am:

Don't engage the AP below 1000' AFE. That's why the MCP is changing from VNAV to VS.

A typo on my part, should have read 1500'.
Andy