TO/GA works when it shouldn't

[lufthansi 0]

Good day!

I figured out that my throttles advance without arming either of the 2 flight directors. The manual correctly states that TO/GA is only available when both FD are engaged. What could be the cause that my TO/GA mode can be activated without any FD or only 1 FD active? It doesn't matter if I'm using the TO/GA buttons on the throttles or the hidden one on the MCP.

 

I'm using Prepar3D V3.2, the latest PMDG 737NGX updates (via the PMDG Updater -> no self caused finger trouble) and only liveries downloaded via the PMDG livery manager (again no finger trouble).

 

I'm running P3D on my iMac using Bootcamp and Windows 7 (also latest updates installed). Everything works wonderful btw. 

 

Maybe I just got something wrong here understanding the system. Even though I read a lot in the forum using the advanced search function. Therefore I'd be delighted getting answers from the pros!

 

Have a nice weekend everybody!

[downscc 1,327]

What is the page that you reference in the FCOM?

[ALF1 15]

I am not a 737 pro BUT, I will tell you what I know.

 

A/T is an independent system from the A/P, but designed to work in conjunction with.

 

If you have takeoff thrust specified in the FMC, and you press TOGA, you will have throttles advancing power and TOGA annunciated by the N1 gauges. This can occur without either FD engaged as long as the A/T is armed.

 

This must not be confused with the TOGA FMA PITCH annunciation, which needs the FD on for the command bars commanding TOGA for pitch.

[JoeDiamond 67]

Alf1 is correct.  If you press TOGA for takeoff with the F/D switches off the A/T will go into N1 mode but you will not get and roll or pitch modes.

 

Flip the F/D switches on and press TOGA again once you are airborne and everything will go back to normal.  Or so I have heard, I'd never do that myself. 

[pete_auau 1,159]

What is the page that you reference in the FCOM?

 

Had  a quick look and  it in fcom2 4.20.2 flight director displays is  the only  thing  that comes  to the question of  the op

 

[lufthansi 0]

Thank you for your replies! Got the message. The FD are necessary to enable the entire "TO/GA mode" shown on the PFD by the FD. I was just wondering because most people, who are having trouble with TO/GA can't get the throttles moving and every time they're told to switch the FDs on.