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

747-400 Flap schedule

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

747-400 Flap schedule

Old 16th Aug 2019, 13:02
  #1 (permalink)  
Thread Starter
 
Join Date: May 2019
Location: Albuquerque, NM
Posts: 27
747-400 Flap schedule

Hi,

Just wondering if anyone could explain in very simple terms the flap schedule for the 747-400. Alternatively, tell me if i have it correct or incorrect! It feels slightly different to the bus way of doing / displaying things!

As i understand it, for flap extension:

select the stage of flap you are approaching as you decelerate. Ie at a few KTS above "5" on the speed tape, decelerating towards it, select flap 5 (from flap 1).

for retraction:

select the stage of flap as you pass the respective number and are accelerating. i.e. when you reach the speed '10' is displayed at, and are accelerating, select flap 10 (from flap 20)

Thanks,

H
Heisenb3rg is offline  
Old 16th Aug 2019, 13:46
  #2 (permalink)  
 
Join Date: Sep 2016
Location: Airborne mostly
Posts: 32
The 747 is different to other types of Boeings, so your interpretation is incorrect.

The flap manoeuvre speeds are flown as minimum speeds for that flap setting. For extension of flaps, you shouldn’t be slower than the flap marker for that present flap setting (ie no slower than Up with flaps up, no slower than 20 with flaps 20.)

For retraction, the flap can be retracted once above the next flap speed. I.e. with flaps 10 extended, once above 5, then flaps 5 can be selected.
andmiz is offline  
Old 16th Aug 2019, 15:13
  #3 (permalink)  
Thread Starter
 
Join Date: May 2019
Location: Albuquerque, NM
Posts: 27
Apologies, I'm probably still confused: is what you say not the same as what I said?
Heisenb3rg is offline  
Old 16th Aug 2019, 20:23
  #4 (permalink)  
 
Join Date: Dec 2007
Location: Luxembourg
Posts: 32
During flap extension, selection of the flaps to the next flap position should be made when approaching, and before decelerating below, the maneuver speed for the existing flap position.
747-8driver is offline  
Old 16th Aug 2019, 20:37
  #5 (permalink)  
 
Join Date: Nov 2008
Location: Europe
Posts: 24
Here's an example
Bluescan is offline  
Old 18th Aug 2019, 07:33
  #6 (permalink)  
 
Join Date: Aug 2007
Location: Seattle KBFI
Posts: 115
For acceleration, you are correct.
For decelerations, you never get slower than the flap bug for the current flaps (min speed for that flap setting). So you slow to or at the UP/ clean bug, then select F1. Now you can decelerate below UP speed after the flaps have extended to 1. Select and wait for flaps 5 prior to dropping speed below the flaps 1 bug. Etc.
bigduke6 is offline  
Old 18th Aug 2019, 15:52
  #7 (permalink)  
Thread Starter
 
Join Date: May 2019
Location: Albuquerque, NM
Posts: 27
I think I've understood it now:

for flap extension, before you reach the number on the speed tape you call for the next flap setting as you can't go slower in the current config.

for retraction, as you pass the number on the speed tape you call for that flap stage.

Cheers everyone
Heisenb3rg is offline  

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.