Hi everyone,

 

When I begin my taxi to the active RWY with a TW of about 500,000 lbs normally, pushing the throttles up to about 25% N1 gets the aircraft to roll quite easily, reaching desired taxi speed within seconds. As soon as I apply some braking action during a turn or something, the same thrust setting wouldn't move the aircraft at all anymore but find myself forced to advance power to about 29 or 30% N1 to get the plane to move. After several times I thought I'd try to set the autobrake to OFF when that happened and the aircraft taxied back normally, as if the autobrake was applying some little braking action. That only happens when I use the brakes. I also noticed that if I use differential braking, the plane wouldn't taxi straight anymore but instead drifts a little bit towards the side where brakes have been used. This is really annoying! The last couple of flights I had to taxi with autobrake set to OFF and set it to RTO just before takeoff roll.

 

I have tried playing around with the sensitivity and null zone settings thinking that they might be the reason of that, but no luck. I can't think of anything else.

 

Is anyone experiencing this? How do you think I can solve this issue?

 

Many thanks in advance!

 

Best,

 

Marc

What's your "desired taxi speed"?

 

regards

I normally taxi at about 15 kts, sometimes reaching 25 at high speed taxiways. But the issue is that in order to reach and maintain something around 15-18 kts, I have to push the throttles up to 29 or 30% at a relatively light weight for a B777. I can't see why the autobrake is applying brake pressure when set to RTO, and that is only initiated after applying manual braking.

 

Thanks!

 

Marc