Autoflight 737

[Olendirk]

Guys,

making a reduced thrust takeoff. deciding to get full power during roll, does pressing the TOGA buttons bring the full takeoff thrust, or do i have to put it manually?

flying a cat II approach, how do you guys fly it, with one or both autopilots?

thanks guys

[Todders]

Yes hit TOGA or you could just disconnect and push the puppies forward and let the eec's help you out.

Cat II Dual Autopilot coupled app. for us

[Denti]

Yup, second TOGA push gives full max rated take off thrust. Do not use if you use a fixed derate setting since it will give max rated thrust and therefore could violate the reduced Vmcg.

CAT II is flown with both autopilots and same procedures as for a normal CAT III a/b except the DH height of course. FLARE/ROLLOUT/LNAV armed for the NG and just normal FLARE armed for the classic.

[c100driver]

Yup, second TOGA push gives full max rated take off thrust. Do not use if you use a fixed derate setting since it will give max rated thrust and therefore could violate the reduced Vmcg.


Second TOGA push removes a thrust reduction only not a derate i.e. a flex or assumed reduction. If you are on a derate takeoff the second push will only go to that derate max.

I you decide that you need more than the derate you will have to manually apply more. Then as Denti said be cautious of Vmcg.

For our B733 operation CatII = autoland = dual autopilot

[Denti]

Might be that our manual is misleading there, however we are encouraged not to advance the thrust lever if we use derate and encounter an engine failure, especially if mixing derate and assumed temperature. The performance is allways conservatively calculated for the one engine case anyway so there is no need to do that. Below the relevant excerpt from the FCOM.

Combination Fixed Derate and ATM

This method uses a takeoff thrust less than the fixed derate takeoff thrust by first selecting a fixed takeoff derate from the FMC. This derate takeoff thrust is then further reduced by assuming a temperature that is higher than the actual temperature. In this case, the thrust reduction authorized by most regulatory agencies is limited to 25% below any certified takeoff thrust rating.

While the ATM portion of the thrust reduction is not considered a limitation for takeoff, the fixed derate portion is. Takeoff speeds consider VMCG and VMCA only at the fixed derate level of thrust for the actual temperature. Since the crew has no indication where the fixed derate limit is, thrust levers should not be advanced unless conditions are encountered during the takeoff where additional thrust is needed on both engines, such as windshear. A thrust increase beyond the fixed derate limit following an engine failure could result in loss of directional control.

To be honest the Vmcg case is normally academic as our V1s are way above Vmcg in all cases but reduced braking action or contaminated runway in which cases we are encouraged to use full rated thrust (derate is allowed, ATM not). And for some reason we do not use derate on the classic, only on the NG, never got an explanation why.

[logotol]

What will happen if you push TOGA on the climbout after you have selected N1?

[A37575]

Assume you are advised by ATC or a preceding aircraft of reports of strong windshear after take off. On that basis you elect not to make a reduced thrust take off as a precaution. If de-rated thrust was originally planned (as well as ATM) would it be considered good airmanship to therefore change from de-rated thrust to full rated thrust in case you need it to counter the expected windshear?

After all, you don't know exactly how dangerous that particular windshear may be and you would look a bit silly in a court of law if the prosecutor put it to you as the captain, that if it was good enough for you to cancel the assumed temperature power because of expected windshear then surely it would have been prudent to delete the de-rate setting as well? After all, it is only money we are talking about in terms of the advantages of various reduced thrust ratings - and not primarily flight safety...

[despegue]

Pressing the TOGA twice on T/O will NOT give you full thrust. A common misunderstanding among crews. You need to manually advance the throttles. Check it next time you fly.

[Todders]

Coming from operating nearly/full a/c pretty much every flight most of the time the de-rate, asum. temp methods to be honest didn't save us a lot but yes we still did it when poss.

As for windshear reported i personally would be straight to full thrust t/o there is no second chance windshear is a variable beast and just cause the guy before got out doesn't mean you will. As you said yourself your gonna look fairly silly at any AAIB hearing if your saying yeah i knew there was windshear but i thought we'd get away with it. Fairly sure even the harshest of CP's couldn't really argue with that logic.