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

Optimum flaps for takeoff

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

Optimum flaps for takeoff

Old 10th Sep 2018, 11:36
  #1 (permalink)  
Thread Starter
 
Join Date: Sep 2018
Location: mumbai
Posts: 1
Optimum flaps for takeoff

Hey all

Wondering what individual airlines like southwest/ Ryanair/ Turkish etc are using for take off flaps. Fixed or optimum?
ks737 is offline  
Old 11th Sep 2018, 16:14
  #2 (permalink)  
 
Join Date: Apr 2008
Location: Nearer home than before!
Posts: 464
Virtually every airline would use optimum as an SOP now, The performance data for most companies is set to exclude F1 for -800/900.
RVF750 is offline  
Old 11th Sep 2018, 20:33
  #3 (permalink)  
 
Join Date: Jan 2006
Location: Between a rock and a hard place
Posts: 1,103
Virtually every airline would use optimum as an SOP now, The performance data for most companies is set to exclude F1 for -800/900.
The vast majority of our take offs are flaps 1, on the -800. That's what "Optimum" often spits out. On shorter runways in suggests higher settings to allow higher ATM.
172_driver is online now  
Old 23rd Sep 2018, 04:26
  #4 (permalink)  
 
Join Date: Apr 2007
Location: EU
Posts: 8
Smile

Originally Posted by ks737 View Post
Hey all

Wondering what individual airlines like southwest/ Ryanair/ Turkish etc are using for take off flaps. Fixed or optimum?
Application calculates the best scenario, and optimum flaps are being used in most of the cases, even though , if compare fuel used Flaps1 nad Flaps 5 TKOF on NG the difference reaches 80kg accordingly. For specific scenarios or airport you can choose fixed flaps ....
Flyer007 is offline  
Old 23rd Sep 2018, 13:47
  #5 (permalink)  
 
Join Date: Jun 2000
Location: Australia
Posts: 4,007
and optimum flaps are being used in most of the cases
Optimum flaps often requires higher takeoff speeds; therefore higher tyre speeds. Higher VR speeds than necessary increase the chances of tyre failure. High speed tyre failure on limiting runway length increase the chances of an over-run if the pilot decides for whatever the reason to abort the take of run. Especially as loss of braking efficiency will occur with tyre failure. No brainer for the safety conscious pilot especially if runway wet
Centaurus is offline  
Old 23rd Sep 2018, 22:27
  #6 (permalink)  

Only half a speed-brake
 
Join Date: Apr 2003
Location: Commuting home
Age: 42
Posts: 3,005
How much of a higher EGT would you scarifice for a lower tyre speed? There must be a break-even point, I guess. But maybe I am just allergic to mis-applications of the S word.
FlightDetent is online now  
Old 23rd Sep 2018, 22:50
  #7 (permalink)  
 
Join Date: May 2009
Location: london
Posts: 137
Originally Posted by Centaurus View Post
Optimum flaps often requires higher takeoff speeds; therefore higher tyre speeds. Higher VR speeds than necessary increase the chances of tyre failure. High speed tyre failure on limiting runway length increase the chances of an over-run if the pilot decides for whatever the reason to abort the take of run. Especially as loss of braking efficiency will occur with tyre failure. No brainer for the safety conscious pilot especially if runway wet
hello Centaurus

do you have any reference material to support the suggestion of increased liklihood of tyre failure with the higher Vr? Having done a fair bit of research into tyre dynamics at university I am not sure where that comes from. It isnt supported from anything I remeber from those days and would be interested to see the reasons for it. Marginally increased wear I could understand but if you remain within the stated performance envelope of the tyre I dont understand what is failing.

honest question, not fishing..
GlenQuagmire is offline  
Old 24th Sep 2018, 09:49
  #8 (permalink)  
 
Join Date: Jun 2014
Location: Earth
Posts: 663
Originally Posted by GlenQuagmire View Post


hello Centaurus

do you have any reference material to support the suggestion of increased liklihood of tyre failure with the higher Vr? Having done a fair bit of research into tyre dynamics at university I am not sure where that comes from. It isnt supported from anything I remeber from those days and would be interested to see the reasons for it. Marginally increased wear I could understand but if you remain within the stated performance envelope of the tyre I dont understand what is failing.

honest question, not fishing..
Incident: Alitalia Cityliner E175 at Rome on Sep 15th 2018, burst both right main tyres on departure

what happened to these tyres?
Officer Kite is offline  
Old 24th Sep 2018, 14:27
  #9 (permalink)  
 
Join Date: Jun 2000
Location: Australia
Posts: 4,007
do you have any reference material to support the suggestion of increased liklihood of tyre failure with the higher Vr?
Fair enough question. The answer is not off the top of my head. The evidence comes from my recollection of reading numerous incident and accident reports over the many years I have been flying aeroplanes big and small. Some of these included tyre failure incidents. One recommendation by McDonnell Douglas does stick in my mind, however.
That is, do not abort for a tyre failure if the failure occurs at speeds more than V1 minus 20 knots. Loss of braking efficiency means V1 as a decision speed becomes invalid. MD would not have issued that warning unless there was evidence that tyre failures at high speed have happened. MD did not supply individual details.
Centaurus is offline  
Old 24th Sep 2018, 14:36
  #10 (permalink)  
 
Join Date: Jan 2000
Location: FL410
Posts: 855
Originally Posted by Centaurus View Post
That is, do not abort for a tyre failure if the failure occurs at speeds more than V1 minus 20 knots. Loss of braking efficiency means V1 as a decision speed becomes invalid. MD would not have issued that warning unless there was evidence that tyre failures at high speed have happened. MD did not supply individual details.
MD could've issued the warning as it is proven much safer to continue a departure and land (normally) with a tyre missing instead of a executing a (rare) high speed RTO. Crew familiarisation comes into play here as well as recognition and non-eventful execution of an RTO.
Skyjob is offline  
Old 25th Sep 2018, 14:14
  #11 (permalink)  
 
Join Date: Apr 2006
Location: Front right seat
Posts: 274
My company has dabbled with the fixed versus Optimum Flap for A330/340 fleet for some time. Tail strike avoidance was one reason given by the fixed flap fans. At the end of the day, it's all just silly really. The manufacturer wouldn't have called it optimum if it wasn't that. Train your pilots properly and use Optimum Flap. In the 2 yrs since moving back to Opt Flap, we haven't seen any tail strikes, or increased tire failures for that matter.
divinehover 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.