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eurowing

how do you properly abort take off?

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hi,

 

i am quite embarrassed to ask this. i thought about creating a fake account for a minute to disguise myself but oh well.

 

a search here gave no results. and RTM did not help me either.

 

i always thought this was a no brainer but i just did a practice RTO and realized it doesn't work as i thought it would.

 

let's say you're on the take off roll with autothrottle i thought you'd apply reverse thrust and then the brakes would automatically kick in (hence RTO on auto brakes). however, moving the throttle levers (Saitek) back and to reverse did nothing. only after i applied toe brakes A/T deactivated, reverse was applied and i slowed down "manually".

 

do i need to disable the throttle override to make this more realistic or what am i missing here?

 

any input is appreciated! (and please don't make fun of me :Worried:)

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I don't push the TO/GA button for auto thrust takeoff. I hit it once with a/t off to arm the fd takeoff mode,and then flip the a/t to arm. If I want to rto, I move the levers to reverse and brakes and spoilers kick in automatically.

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The best practice regardless if you use auto-throttle on takeoff, is to disconnect it in any RTO situation... Much simpler, and a natural reflex action is to step on the brakes which gives more braking power than RTO setting.. I don't trust computers in takeoff or landing situations..

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I use TOGA all the time, I would click the auto throttle off and bring in the reverse thrust. Auto brakes kick in and you raise the spoilers.

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  • Close thrust levers
  • Disengage autothrotle
  • Raise speedbrake lever
  • Apply max reverse thrust
  • Make sure braking is happening (RTO autobrake only effective 90kts or above), otherwise max manual braking
  • Stop the aircraft, set the parking brake.
  • Diagnose failure and act appropriately

 

Henry Lidster

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Just a sidenote... Manual braking is NOT advised when above 80 kts. (high energy => RTO kicks in). The reasoning behind this is the following: on less than optimum runway surfaces, Max Manual braking will be more likely to lock the wheels, rendering the airplane (nearly) uncontrollable. The RTO setting will provide much better braking action than you can manually achieve.

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Hmm... reading it back, I expressed myself wrongly.

What I meant to say was: the method of braking differs... When you are braking Manually, Antiskid will cut in to prevent the wheels locking (hence, releasing the brakes), this can still render the plane incontrollable, albeit less so than planes before the NGs (which is where I made the error with locking up, thinking about all the 737 series, not just the NG). With RTO, the Antiskid will also kick in, but the brakes will be held to "just before" locking, which means better braking action in total.

Not sure if I explained it in a correct, coherent way, I hope it's understandable.

That's how I understood it, correct me if I'm wrong.

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I don't push the TO/GA button for auto thrust takeoff. I hit it once with a/t off to arm the fd takeoff mode,and then flip the a/t to arm. If I want to rto, I move the levers to reverse and brakes and spoilers kick in automatically.

 

Definitely not standard procedure there...

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Definitely not standard procedure there...

Sucks to make a nearly accurate sim of the NG and people don't use it correctly?

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Found this on you tube, hop it helps

 

 

Credit goes to the maker of this tutorial

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Found this on you tube, hop it helps

 

 

Credit goes to the maler of this tutorial

I havent watched it, but it looked pretty good

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Hi,

 

There is also a diffenrence in behaviour during RTO according to the speed.

 

for the brakes:

FCOM2 p. 14.20.4/14.10.4

 

And for the speed brakes:

FCOM2 p.9.20.17/9.10.0

 

Bert Van Bulck

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Yeah, I know it isn't standard, but I tend to use as little automatization as I possibly can so I don't use to/ga or autoland for that matter. I always disconect the autopilot before capturing the localizer and do it manually. As for the use of reverse thrust, I only practised rto-s in normal circumstances with everything working just as a test. In case of engine fire or failure, I wouldn't use reverse and I would extend the spoilers manually.

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The best practice regardless if you use auto-throttle on takeoff, is to disconnect it in any RTO situation... Much simpler, and a natural reflex action is to step on the brakes which gives more braking power than RTO setting.. I don't trust computers in takeoff or landing situations..

 

I may have misunderstood your post but to be clear RTO gives the maximum possible braking. It applies the full 3000 psi of hydraulic pressure. The pilot can not do better than RTO.

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From SOP.. "RTO Autobrakes are equal to Maximum Manual Braking". Ok, maybe not more, but equal..

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Can you perform take off abort correctly if you set override AT to "never" in FMC options?

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Can you perform take off abort correctly if you set override AT to "never" in FMC options?

 

Only if you change sequence of first two actions. First disengage A/T, second close thrust levers.

If you set "In HOLD/ARM mode only", you can abort correctly after 84 knots.

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Only if you change sequence of first two actions. First disengage A/T, second close thrust levers.

If you set "In HOLD/ARM mode only", you can abort correctly after 84 knots.

 

Yea, I use HOLD/ARM mode only and I can perform procedure correctly, but I was curious is it able to do the same in "never" mode. Tnx for answer :smile:

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Didn't know this was allowed.

 

I think only if there is symmetrical thrust available. If it is available with asymmetric thrust, I would imagine that it would only be available in dry, non-crosswindy-gusty-blow-you-off-the-runway conditions.

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From SOP.. "RTO Autobrakes are equal to Maximum Manual Braking". Ok, maybe not more, but equal..

To get maximum manual braking, you'll have to stand on the brakes real hard. In doing that, you'll probably have less control on the other control surfaces (steering, both rudder and nose wheel, ailerons for possible upwind situations,...). On top of that, Max Manual Braking describes what the plane can deliver, not what you can deliver. On an NG, it's VERY hard to manually equal those 3000 psi the RTO setting will give you, while maintaining direction.

Not using the RTO setting is like saying "Yeah, there's an autopilot, but I can fly much better myself, I don't use it at all." There are scenarios where computers and electronics outweigh human actions. This is just about always one of them.

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I think only if there is symmetrical thrust available. If it is available with asymmetric thrust, I would imagine that it would only be available in dry, non-crosswindy-gusty-blow-you-off-the-runway conditions.

That's why I had my original thought. There are quite a few restrictions concerning reverse thrust during aborted take-off.

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