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

747 Classic question

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

747 Classic question

Old 19th Jun 2019, 09:47
  #1 (permalink)  
Thread Starter
 
Join Date: Aug 2007
Location: No Way
Age: 68
Posts: 30
Received 0 Likes on 0 Posts
Thumbs up 747 Classic question

I never flew the classic, so I have no clue. Saw this on fb:

“On long range sectors, where fuel could be critical, and dodgy weather they (a kangaroo airline) would fly single pac, the air became very stuffy, it was hard to breathe when working, a quick visit to the flight deck confirmed it, only one pac running, they weren't supposed to do it, but they did.”

Could it fly with one pack ops?





Oyster Shucker is offline  
Old 19th Jun 2019, 10:34
  #2 (permalink)  
 
Join Date: Jun 2001
Location: OZ
Posts: 1,116
Received 11 Likes on 5 Posts
Nope.
For the B747-300 I think there was a "half flow" option on the pack controllers for use in crz. SOP's mandated what pack selection was used and 1 pack was not one of them. Personally I, FEO, only ever used half pack on the Capt direct instructions coz it saved 3/5 of 5/8 of FA fuel. The possible fuel savings disappeared in the static like heavy airframes - OJU was heavy and always had difficulties BKK-FCO while other aircraft made it OK.
mustafagander is offline  
Old 19th Jun 2019, 10:42
  #3 (permalink)  
Thread Starter
 
Join Date: Aug 2007
Location: No Way
Age: 68
Posts: 30
Received 0 Likes on 0 Posts
Originally Posted by mustafagander
Nope.
For the B747-300 I think there was a "half flow" option on the pack controllers for use in crz. SOP's mandated what pack selection was used and 1 pack was not one of them. Personally I, FEO, only ever used half pack on the Capt direct instructions coz it saved 3/5 of 5/8 of FA fuel. The possible fuel savings disappeared in the static like heavy airframes - OJU was heavy and always had difficulties BKK-FCO while other aircraft made it OK.
Yeah. I would have thought that a single pack ops would affect ventilation, pressurisation and equipment cooling?

Is half pack similar to low flow on the -400? and was that with 3 or 2 packs ON?

cheers
Oyster Shucker is offline  
Old 19th Jun 2019, 10:48
  #4 (permalink)  
 
Join Date: Nov 2001
Location: Delta of Venus
Posts: 2,383
Likes: 0
Received 2 Likes on 1 Post
Some airlines had an SOP to switch off ONE pack in the cruise ( so 2 packs still running) to reduce fuel burn, in theory, by a small percentage.
Yes, the -300's had a half pack setting as well & low flow on -400. Personally I thought the air on a highly populated 747 was never great in terms of quality or quantity even with 3 packs running.
Private jet is offline  
Old 19th Jun 2019, 10:58
  #5 (permalink)  
Thread Starter
 
Join Date: Aug 2007
Location: No Way
Age: 68
Posts: 30
Received 0 Likes on 0 Posts
from b747classic.co.uk

One Pack Operation:
Galley / Lavatory exhaust fan Auto / On
Recirculating fans On
Gasper fan On

Supplemental vent fans On”


Is 1 pack ops possible?
Oyster Shucker is offline  
Old 19th Jun 2019, 11:06
  #6 (permalink)  
 
Join Date: Feb 2018
Location: East of Westralia
Posts: 675
Received 100 Likes on 29 Posts
On the 747-400 we used to have cabin crew ring up / visit the flight deck and ask for more oxygen.. They would not believe that we had no such control.. I’d take the original post with the required pinch of salt...
ScepticalOptomist is offline  
Old 20th Jun 2019, 01:44
  #7 (permalink)  
 
Join Date: Apr 2004
Location: Planet Earth
Posts: 2,083
Likes: 0
Received 8 Likes on 7 Posts
In the account of the Qantas 744 that flew non stop from London to Sydney many different fuel saving techniques were used


One of them was to use only one pack for
the entire journey, towards the end of which
they were at FL450


Of course I don’t think they had any more than 20 people on board including pax and crew
stilton 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

Copyright © 2024 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.