Takeoff / TOGA

[Zimmerbz 166]

I am re-learning the 737 after flying the A320 for a few years.  I have a question on takeoff.  When do you or don't you use TOGA on takeoff?  I ask because every time I press TOGA after the engine stabilizes it un arms LNAV and VNAV and won't let me select it for a while.  Therefore it makes it difficult to follow the FD correctly.  I'm sure I am doing something incorrectly so I wanted to see what the consensus is.  Thanks!

[Olympic260 415]

What do you mean disarms them? The MCP lights or the FMA annunciations? 

[Zimmerbz 166]

Both. 

[downscc 1,327]

TOGA is always used for safety reasons in case you need to do a RTO or lose an engine, plus it ensures you going to get reference thrust.  I don't understand your complaint.  TOGA takeoff you follow the TOGA pitch line after lifting off using the HGS.  You engage HDG or start to follow LNAV above 400 ft or as required by the procedure you are flying.  If it is unarming then it is because you are moving your throttles during takeoff roll above 80kts.

[Zimmerbz 166]

 

9 minutes ago, downscc said:

TOGA is always used for safety reasons in case you need to do a RTO or lose an engine, plus it ensures you going to get reference thrust.  I don't understand your complaint.  TOGA takeoff you follow the TOGA pitch line after lifting off using the HGS.  You engage HDG or start to follow LNAV above 400 ft or as required by the procedure you are flying.  If it is unarming then it is because you are moving your throttles during takeoff roll above 80kts.

I guess my main question is when should you use it.  This answers my question.. Thanks!

[Capt. Windh 3]

1 hour ago, downscc said:

 If it is unarming then it is because you are moving your throttles during takeoff roll above 80kts.

 

I also have a question regarding this. When I have klicked TOGA I usually move the throttles afterwards (to somewhat make them correspond with the physical setting that the motorized levers would do IRL) but even at low speeds this disarms the A/T all together and I have to re-arm it instantly.

 

(I have set manual throttle to NEVER override in the NGX settings)

 

Any ideas on when it would be "safe" to move the physical throttle, or is there any other way around it?

[downscc 1,327]

I always set my throttles up for override in arm or hold only.  For takeoff, I stand up the throttles and press TOGA when N1 exceeds 60% and then push throttles all the way forward.  This does not disconnect the A/T.  Normally on reaching 80 kts the FMA thrust switches from N1 to hold (depending a 737/747/777 there are different variations, the 737 is THR HLD). The servos are disconnected and the pilot can move the throttles which will cancel TOGA.  Above V1 the FMA returns to N1 and you takeoff.  More info in FCOM 4.20.6 among other sources.  Also see the FCTM.

[Capt. Windh 3]

Thanks Dan. I'm not really sure why mine makes it disconnect then.. As I have set it to NEVER, I would assume that it wouldn't interfere once TOGA is pressed.

 

 

15 minutes ago, downscc said:

I always set my throttles up for override in arm or hold only.  For takeoff, I stand up the throttles and press TOGA when N1 exceeds 60% and then push throttles all the way forward.  This does not disconnect the A/T.  Normally on reaching 80 kts the FMA thrust switches from N1 to hold (depending a 737/747/777 there are different variations, the 737 is THR HLD). The servos are disconnected and the pilot can move the throttles which will cancel TOGA.  Above V1 the FMA returns to N1 and you takeoff.  More info in FCOM 4.20.6 among other sources.  Also see the FCTM.

 

[downscc 1,327]

Never is not a good idea.  For example, using FLCH the A/T will go into hold and there you can use thrust to control descent rate.  Being able to use the throttles in hold mode is important to me.

[Capt. Windh 3]

3 minutes ago, downscc said:

Never is not a good idea.  For example, using FLCH the A/T will go into hold and there you can use thrust to control descent rate.  Being able to use the throttles in hold mode is important to me.

 

That's a good idea. I'll give it a try. Thanks Dan.