What causes AutoBrakes to snap back from RTO to off

[Boomer 1,619]

So on the ramp before taxi (or even during taxi) when I try to select autobrakes RTO it just snaps back to off.

Havent been able to discern a pattern as to why as yet.

Thoughts?

[scandinavian13 5,192]

15 minutes ago, Boomer said:

So on the ramp before taxi (or even during taxi) when I try to select autobrakes RTO it just snaps back to off.

Havent been able to discern a pattern as to why as yet.

Thoughts?

Garbage data/calibration on your hardware. Recalibrate and set a proper null zone.

[Boomer 1,619]

2 hours ago, scandinavian13 said:

Garbage data/calibration on your hardware. Recalibrate and set a proper null zone.

So then an issue with my HOTAS x65 throttle null zone ya think?

I will check that option out and advise back, brother Kyle.

[scandinavian13 5,192]

19 minutes ago, Boomer said:

So then an issue with my HOTAS x65 throttle null zone ya think?

Probably. There's something causing it to kick off, and it's likely hardware.

[Qavion2 39]

The only thing which can cause the RTO to trip to OFF is liftoff, power failure, normal antiskid or autobrake failure. Unless your joystick is simulating the aircraft lifting off the ground, then it shouldn't be the joystick.

RTO will arm even with the IRUs off and the park brake set.

[Chock 17,769]

10 minutes ago, Qavion2 said:

The only thing which can cause the RTO to trip to OFF is liftoff, power failure, normal antiskid or autobrake failure. Unless your joystick is simulating the aircraft lifting off the ground, then it shouldn't be the joystick.

On the real thing maybe so, but in the sim there's all kinds of stuff going on and hoops the developers have to jump through to get FS to depict a 747, so in the sim it certainly could be the joystick spiking or sending spurious signals.

[anden145 2,284]

14 minutes ago, Chock said:

On the real thing maybe so, but in the sim there's all kinds of stuff going on and hoops the developers have to jump through to get FS to depict a 747, so in the sim it certainly could be the joystick spiking or sending spurious signals.

Indeed. There's an easy way to test. Disconnect the joystick and see if the behavior continues... 

[Jovabra 18]

9 hours ago, Qavion2 said:

The only thing which can cause the RTO to trip to OFF is liftoff, power failure, normal antiskid or autobrake failure. Unless your joystick is simulating the aircraft lifting off the ground, then it shouldn't be the joystick.

RTO will arm even with the IRUs off and the park brake set.

In the "real world" also hitting the brake pedals.

Regards
Jo va Bra

[JRBarrett 3,048]

3 minutes ago, Jovabra said:

In the "real world" also hitting the brake pedals.

Regards
Jo va Bra

Hitting the brakes after landing with auto brakes set to 1 through 4 will disarm them, but manual braking will not disarm RTO. Many crews arm RTO mode as part of standard checklists post-engine start, before beginning their taxi to the runway, and manual braking will certainly be employed during the taxi.

 

[Jovabra 18]

According MM 32-42 Autobrake deactivated.
1.. Brake pedal press>750psi
2.  Throttles are advanced
3.  Speed brake lever is moved to down detent

Regards
Jo va Bra

[skelsey 765]

7 minutes ago, Jovabra said:

According MM 32-42 Autobrake deactivated.
1.. Brake pedal press>750psi
2.  Throttles are advanced
3.  Speed brake lever is moved to down detent

Regards
Jo va Bra

But not in RTO mode. Think about it: if those conditions also applies to RTO it would disarm immediately the thrust levers were advanced for takeoff, which would be somewhat counterproductive!

[Jovabra 18]

My mistake. It is not in the RTO mode but in the Auto Brake mode.

regards

Jo va Bra