Go Back  PPRuNe Forums > Flight Deck Forums > Tech Log
Reload this Page >

747-400 alternate gear extension

Tech Log The very best in practical technical discussion on the web

747-400 alternate gear extension

Old 23rd May 2001, 00:09
  #1 (permalink)  
Posts: n/a
Question 747-400 alternate gear extension

the uplocks that hold the gear up are released by...hydrolic or electric...when the alt gear extension switch is pushed ??
bear in mind that gear lever is in off position(in checklist)and hyd system loss may exist..

many thanks..
Old 23rd May 2001, 01:46
  #2 (permalink)  
Posts: n/a

am I thick or is it that I just dont understand the question?
Old 23rd May 2001, 01:48
  #3 (permalink)  
gas path
Posts: n/a

One switch for the nose and body gear (failure of hyd. sys. 1).
One switch for the wing gear
(failure of hyd. sys. 4).
Old 23rd May 2001, 14:16
  #4 (permalink)  
Cornish Jack
Posts: n/a

The Alternate gear actuation is by electric motors which drive the the uplock jaws through 180 degrees. The jaws are open ended - the uplock roller drops out and the gear drops under gravity and air loads. Same type of system for both Wing and Nose and Body.
Old 23rd May 2001, 14:39
  #5 (permalink)  
gas path
Posts: n/a

Providing of course that the system first released the door actuator locks and the spring bungee is juuussssst strong enough to push the downlock linkage overcentre.

[This message has been edited by gas path (edited 23 May 2001).]
damned dys.. dysle.. dyslexia!

[This message has been edited by gas path (edited 23 May 2001).]

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off

Thread Tools
Search this Thread

Contact Us - Archive - Advertising - Cookie Policy - Privacy Statement - Terms of Service - Do Not Sell My Personal Information

Copyright 2018 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.