PPRuNe Forums - View Single Post - B747 Taxi & Turning Operations
View Single Post
Old 20th Apr 2015, 02:50
  #4 (permalink)  
JammedStab
 
Join Date: Apr 2008
Location: nowhere
Posts: 0
Remember, only the body gear has steering, not the wing gear so you could never set it up in the same way as the B-52 even if there was a way to activate it from the cockpit for landing(which there is not).

http://cdn-www.airliners.net/uf/1137...phpJa7h1s.jpeg

Going from memory, as the tiller moves beyond 20 degrees of nosewheel steering, the body gear for the -400 starts to turn in the opposite direction to a maximum of 13 degrees presumably at max nosewheel steering angle(although that is just a guess). But, this is only at slower speeds. It is disabled once accelerating through 20 knots and enabled when decelerating through 15 knots so it is for low speed operation only.

I'd say in general that you never really think about it. Until it is MEL'd as inoperative that is. That being said I did see one pilot work his way through a 120 degree turn onto the parallel taxiway from the high speed exit in this condition so normal ops really are not affected but turning radius for close-in ops should be considered.

Non-centered body gear will cause damage if retracted. Therefore, there is a takeoff warning if it is not centered when power is advanced for takeoff. So prior to adding a bunch of thrust for takeoff it is best to make sure the tiller is centered to avoid a false warning. I believe the gear lever will not move to the Up position if the body gear is not centered(or if it is not tilted) and therefore the override function should not be used until it is verified why the handle will not move to Up(such as an EICAS message).

Last edited by JammedStab; 26th Apr 2015 at 14:27.
JammedStab is offline