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

A340 vs 747-400

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

A340 vs 747-400

Thread Tools
 
Search this Thread
 
Old 19th Oct 2000, 19:27
  #1 (permalink)  
cortilla
Guest
 
Posts: n/a
Post A340 vs 747-400

a friend of mine is capt. with SIA, and whenever he flys to singapore on 747-400, he's always complaining that A340's ahead of him are always slowing him down. How true is this, or is he just a man who likes to moan (like most of us humans)
 
Old 19th Oct 2000, 20:47
  #2 (permalink)  
Lucifer
Guest
 
Posts: n/a
Post

The A340 does has a slightly slower cruising speed than the 747-400. Thus it is unable to use some routes such as the new Tokyo route that BA is using with -400s due to certain restrictions.
 
Old 19th Oct 2000, 20:49
  #3 (permalink)  
jtr
Guest
 
Posts: n/a
Post

The 340 plods along at around 0.82, whilst the -400 is more in the region of 0.84 or 0.85 (depend on the airlines op. proc. of course) So yes, at the same level the the -400 will close. The 340 will usually step higher earlier though (at heavy weights) so not always a prob. As you say human nature, like being in the circuit in a C210, and bitching about the Tomohawk in front.

Lucifer, what routes place a restriction on min. speed? I am aware of Mach no. technique etc, but have not heard of a route not being available to an a/c type per se. In my experience, he who is in front generally get to set the pace.

[This message has been edited by jtr (edited 19 October 2000).]
 
Old 19th Oct 2000, 21:51
  #4 (permalink)  
ManaAdaSystem
Guest
 
Posts: n/a
Post

There used to be some airways in Russia with a max speed of .80. Maybe still?
The guy in front has the right of way. A simple fact that a few pilots seem quite unaware of.
 
Old 20th Oct 2000, 17:28
  #5 (permalink)  
Lucifer
Guest
 
Posts: n/a
Post

I don't know details, but BA are flying a new Tokyo route with -400s, which Virgin are unable to use with their A340s.
 
Old 20th Oct 2000, 19:00
  #6 (permalink)  
jtr
Guest
 
Posts: n/a
Post

Sound like it may be either an eng-out prob., or an O2 capacity one. The Virgin 340's have the smaller CFM on them, and maybe can't maintain terrain clearence if one goes out, or it may be that they can maintain the required alt., but don't have the O2 to be able to stay high enough long enough.
On the NOPAC routes between Anchorage/Vancouver etc, and Japan and further, you will often hear speed jockeying going on. Whoever is in front is entitled to stick to whatever speed they choose. Some of the 340 guys even slow down if the -400 behind them complains too much.

[This message has been edited by jtr (edited 20 October 2000).]
 
Old 22nd Oct 2000, 00:26
  #7 (permalink)  
tired
Guest
 
Posts: n/a
Post

Lucifer/jtr - there's a high speed airway in eastern Siberia that has a min. speed of .84 or .85 (can't remember the exact speed), so it's effectively limited to 747s.

Despite all the whingeing from the Jumbo brigade there's not a hell of a difference in TAS between .82 and .85 - a jumbo picks up maybe 20 minutes in a 12 hour flight. Not that you'd believe it listening to all the moaning coming from the sharp end
 

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



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.