B777 Nws

[ZAGORFLY]

We all know about the steering 3rd axel og Main Langin Gear (MLG). what happen when you push Back? is it reacting to the NWS angle? (no, because the NWG HYD is disconnected or ..)
Just keep centered and under stress enough to sometime give an Gear disagree EICAS during T/O.

[Old Smokey]

stefanoperer,

The next time that you do a push-back, take note that the steering tiller still follows up the actual Nosewheel position, which is castoring in response to the tug's movements. In response to the tiller and nosewheel position, the Main Gear Steering still operates normally, as, even though the Nosewheel steering has been isolated, the Main Gear steering is still hydraulically powered and operates in the normal sense.

Regards,

Old Smokey

[ZAGORFLY]

Thank you very much inedeed.

Therefore that is why Push back is not permitted if the hydraulic system is not pressurized! This in order to power the main landing 3rd axel steering capabilities according to the tiller angle deviation, since the NSW is disconnected from the Hydro power. Correct?

[Old Smokey]

stefanoperer,

That is why Push back is not permitted if the hydraulic system is not pressurized. If unpressurized, the Main Gear Steering would attempt to castor, in this case towards 'full throw'. This is why the Main Gear steering must be locked into the straight position if inoperative.

Regards,

Old Smokey