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Peter de Bruin

Rejected Take-off mode

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Tried the rejected take-off between 80knts and V1 without success as the autobrake feature failed. Tried it as follow : started the take-off with stable engines moving up to with brakes on, brakes off - start of roll and engaged the TO mode - saw armed in PFD earlier, pushed the yoke levers all the way up and waited to pass the 80knts maintaining centre line, when passing the 120knts pulled the levers all the way back - auto brake did not come in. Maybe I do something not correct ?

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If you told the autothrottle to disregard your HW throttle position, it will not work like that. First you must disengage AT, and then pull the throttles to idle.

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For a rejected take off, as I recall it: Make sure the auto brakes are set in RTO. Then, do the takeoff run as you did, when you want to reject the takeoff, pull the throttles to idle, and engage the reversers. As soon as you engage the reversers, the autobrakes should come on. I'm not at home so I cannot try it, but I hope this helps.

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For a rejected take off, as I recall it: Make sure the auto brakes are set in RTO. Then, do the takeoff run as you did, when you want to reject the takeoff, pull the throttles to idle, and engage the reversers. As soon as you engage the reversers, the autobrakes should come on. I'm not at home so I cannot try it, but I hope this helps.
1. Like i said, either you have AT override on, or you need to turn off autothrottle.2. When you engage the reversers, the speedbrakes should come on, not autobrakes.

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1. Like i said, either you have AT override on, or you need to turn off autothrottle.2. When you engage the reversers, the speedbrakes should come on, not autobrakes.
Like I said: "as I recall it"... I stand corrected.Throttles to idle should engage RTO braking.When reversers are engaged the speedbrakes are deployed.

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Like I said: "as I recall it"... I stand corrected.Throttles to idle should engage RTO braking.When reversers are engaged the speedbrakes are deployed.
Sorry if i sounded a bit harsh, it was unintentional. I just wanted to clear some things up.

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Yes you have to disengage the autothrottle. I believe only the wheel brakes are the automatic method of slowing down (when in RTO mode) Idling the throttle, applying reverse thrust and raising the speedbrake all need to be done manually.Discussed in Section 3.24 in the Flight Crew Training Manual or herehttp://www.smartcockpit.com/data/pdfs/plane/boeing/b737/instructor/B737-Rejected_Takeoff_rev_03.pdf

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With RTO selected:

- if the takeoff is rejected prior to wheel speed reaching 90 knots autobraking is not initiated, the AUTO BRAKE DISARM light does not illuminate and the RTO autobrake function remains armed.

- If the takeoff is rejected after reaching a wheel speed of 90 knots, maximum braking is applied automatically when the forward thrust levers are retarded to IDLE.

Just checked the console while pulling the trust levers back at 120 knts and to my suprise the levers in the plane remain frozen at 100 percent. When I move the levers in normal conditions all works well. It seems that when N1 is engaged they are locked to the full trust position. When I use the F1 ( instant cut of power ) on the keyboard Rejected take of works as described above in point 2 - Maximum breaking, Iddle trust without the need to disengage the autotrottle switch.

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Just checked the console while pulling the trust levers back at 120 knts and to my suprise the levers in the plane remain frozen at 100 percent.
Why surprised? Cristi Neagu was probably right with his first reply.

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I tried this for myself some time ago. Without AT disarm, nothing happens. If you want the throttles to behave as they do in the real plane, go into the CDU, in the simulation options, and change AT override to "always", or something along those lines. Can't remember the exact option. That way, when you pull back on the throttles, autobrakes engage. The downside is that any kind of jitter or spike in your hardware throttles will disengage autothrottle.If you choose to never override the AT, you HAVE to disengage AT prior to throttle reduction to engage autobrakes.

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Moving the trotlle should be reflected in the NGX cockpit anyway... if I follow your argument. However it is frozen at 100 percent and sticks there no matter what. Then F1 is functional ( wich represent the trottle function via the keybord ) and high speed abort functions like it should, maximum breaking is automatically applied. In my opinion flicking a switch during high speed abort is not how it should be and in agreement with documentation - and for instance Level-D 767.In a low speed zero to 80knts I agree with you all the way. That's indeed the way how it works. It seems we have 3 items on NGX plate - one is the yoke not reflecting the actual movement of the pilots input, F1 invokes different behavior, and implementation of high speed abort without flicking of a switch first.

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there is an option to disable the ""lock" of the throttle but you will have troubles.To disengage the AT in real life the switches are on the throttles, you can do the same on your joy. And real throttle are motorized, your joy not, so, disabling the "lock" of the joy command when AT is used will cause sometimes unattended movement of the levers according to the last selected.Try to disable from the option the option that locks the throttle when in thrust hold.

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