TO/GA and R-TO

[Guest B742FAN]

Let me start off by just saying how much I enjoy this bird. It's pretty much all I fly now. My question is about this TO/GA mode and takeoff. I am new to these types (my other payware addons are the 727 and RFP) of engine automation. So far when I takeoff I make sure the FMC is completely set up, do my taxi checklist (FAARTS) - flaps, altimeter, autothrottle, route (fmc), trim, squawkcode. Once I am lined up for on funway I make sure A/T is armed and just roll the throttles up. They seem to retard properly as per my selection on the FMC (usually CLM-2).On the EID it says the mode is R-TO. I presume it would say TO/GA if i pressed this top-left screw. However, If I push that screw just before rolling the throttles forward, nothing happens. Can someone explain TO/GA for me?Thank youJosh Laughlinjlaughlin@annnex.net

[ahaka 0]

R-TO stands for reduced takeoff thrust. This text only indicates which thrust limit mode is selected, not the A/T mode activated. The A/T information is displayed on PFD.

[Guest B742FAN]

OK so what does TO/GA actually do?Josh Laughlin

[Guest acroshaw]

TO/GA stands for TakeOff or Go Around and basically it commands the maximum thrust for the engines as defined on the N1 limit page. Obviously in a go around you want maximum thrust, as in a take off. However, in a takeoff you can choose to use less than maximum, i.e a derated takeoff to save on engine wear and tear and reduce noise, which is the option most pilots choose except on very short runways. It's better than just firewalling the throttles, as the autothrottle keeps the engines within limits. Hope this helps,ant

[Guest Ian_Riddell]

"Obviously in a go around you want maximum thrust, as in a take off."Not necessarily... See previous recent messages on this subject ;-)Cheers.Ian.P.S. Only a double push should give you the N1 limit during a Go-Around

[Guest B742FAN]

OK, but even without clicking TO/GA, I am getting limited thrust depending on what I set my CLB thrust parameter on the FMC. So the throttles don't seem to firewall the N1 when TO/GA is NOT engaged as long as I set it in the FMC. I always use CLB-2 anyway. Don't want to burn out my new PMDGCFM's :)Josh Laughlin

[Guest acroshaw]

you can certainly have fun with this fmc josh. There is a technique in the fmc guide by bill bulfer that works well with this bird, he calls it flying the high speed buffet boundary. Basically, if you want to gain some time on your eta, enter a cruise speed that is unattainable due to weight etc. The fmc will calculate and fly the max allowed airspeed considering the buffet boundary, and this will slowly increase as you burn off fuel. Just remember to reduce it well before t/d, otherwise vnav will disconnect on overspeed.Try it, it works quite well, and it shows the quality and depth of this product, even without su2,cheers,antp.s.I gonna try a missed approach now, see what all the fuss is about!

[Donstim 109]

"It's better than just firewalling the throttles, as the autothrottle keeps the engines within limits."The electronic engine control keeps the engines "within limits" even when the thrust levers are "firewalled."Don S.

[Guest Ian_Riddell]

"The electronic engine control keeps the engines "within limits" even when the thrust levers are "firewalled.""Good point, Don.You shouldn't see, say, red N1 displays unless there is something wrong with the EEC's (even when pushing the thrust lever forward manually). The EEC's compute idle and max thrust and give a particular thrust for a particular lever angle. 0 to 2.4 degrees is idle, 44 degrees is max climb, 52 degrees is max T/O (or G/A) and 58 degrees is Max Certified Thrust.Cheers.Ian.

[Guest acroshaw]

According to my sources (i.e Mr Bulfer again!), max N1 is 104%. If the fmc is not providing the a/t system with N1 limit values, the autothrottle uses a degraded N1 thrust limit from EEC and "A/T lim" is displayed in white. Nice to see it implememted so well,cheersant