Go Back  PPRuNe Forums > PPRuNe Worldwide > Australia, New Zealand & the Pacific
Reload this Page >

F100 - Overshot Runway at Newman Airport (9/1/2020)

Australia, New Zealand & the Pacific Airline and RPT Rumours & News in Australia, enZed and the Pacific

F100 - Overshot Runway at Newman Airport (9/1/2020)

Old 5th Sep 2021, 04:02
  #121 (permalink)  
 
Join Date: Jun 2006
Location: 3rd rock from the sun
Posts: 2,146
Likes: 0
Received 0 Likes on 0 Posts
Originally Posted by neville_nobody View Post
You're confusing pre dispatch with post dispatch. Post dispatch you are using whatever approved system you have available which may even have the 15% factor built in them.

The pre dispatch 1.67 figures are off the maximum braking performance of the aircraft. You couldn't factor 67% on a normal everyday landing performance you'd need 3500m+ everywhere you went.
Read the posts by Bloggs and Kitchen
morno is offline  
Old 5th Sep 2021, 04:11
  #122 (permalink)  
 
Join Date: Jun 2006
Location: 3rd rock from the sun
Posts: 2,146
Likes: 0
Received 0 Likes on 0 Posts
Originally Posted by Capn Bloggs View Post
Curtain Twitcher, that's not a new instrument, it's only a CAAP. Essentially, nothings changed except that there is now a para on "very wet" landings.

IMO the fundamental flaw in all of this was the LDR change from +67% of demonstrated/actual to +15% just because you're now airborne (11.2 and it's Note). A bit like the old 45min FR for planning verses 30min FR after you get going. Illogical.

15% was always going to cause grief, and will continue to do so until somebody steps up and says the current rules are "an ass" and slaps some additional buffers on. Personally, if I don't have full preflight factors (1.67 or 1.92), even when airborne, I'm not doing it unless I'm in dire straits.
Referred Post
morno is offline  
Old 5th Sep 2021, 04:30
  #123 (permalink)  
 
Join Date: May 2013
Location: Mostly here, sometimes over there...
Posts: 320
Likes: 0
Received 0 Likes on 0 Posts
......yeah, and that messed with my fragile mind too, but I figured Bloggs may have just been drinking a lot before posting.
Buttscratcher is offline  
Old 5th Sep 2021, 04:51
  #124 (permalink)  
 
Join Date: Jul 2003
Location: Somewhere
Posts: 2,884
Likes: 0
Received 0 Likes on 0 Posts
There appears to be confusion about definitions. Have a look at Hamilton Island and tell me how anyone in an airliner can dispatch there with a 1.67 factor and what sort of performance is needed to make the factoring work.
neville_nobody is offline  
Old 5th Sep 2021, 05:54
  #125 (permalink)  
 
Join Date: Nov 2001
Location: Australia/India
Posts: 4,519
Likes: 0
Received 0 Likes on 0 Posts
The factor could be 1.92 for the 'dispatch' maximum weight!

I can't work out why s 11.1(b) of CAO 20.7.1B makes specific provision for the wet destination runway scenario for the 'dispatch' maximum weight but s 11.2 does not for the 'in air' calculation. If you know, before you take off, that the destination runway is or may be wet, the maximum take off weight has to be calculated on the basis that the landing distance required will be 1.92 times the distance required to land in the dry and, apparently, that requirement applies irrespective of whatever landing distance data has been supplied by the holder of the type certificate for the aircraft. However, once the actual destination conditions are known the factor changes to 1.67 or, in the case of an aircraft whose type certificate holder has supplied actual distance data, 1.15. Whattha?

If the actual conditions on arrival turn out to be wet as forecast, what magic changes the risk from one requiring a 1.92 factor to 1.67 or 1.15 factor in the same aircraft?
Lead Balloon is online now  
Old 5th Sep 2021, 07:00
  #126 (permalink)  
 
Join Date: Mar 2002
Location: Seat 0A
Posts: 8,281
Received 0 Likes on 0 Posts
The irony, Morno, is that your Flysmart (should) give you a 167% landing distance calculation for dispatch.
Capn Bloggs is offline  
Old 5th Sep 2021, 07:03
  #127 (permalink)  
 
Join Date: Mar 2002
Location: Seat 0A
Posts: 8,281
Received 0 Likes on 0 Posts
......yeah, and that messed with my fragile mind too, but I figured Bloggs may have just been drinking a lot before posting.
All I'm saying is that routinely landing with only 15% over the actual landing distance required ie 50ft over the fence to a max-effort full stop, is going to eventually end in grief.
Capn Bloggs is offline  
Old 5th Sep 2021, 08:25
  #128 (permalink)  
 
Join Date: Jun 2006
Location: 3rd rock from the sun
Posts: 2,146
Likes: 0
Received 0 Likes on 0 Posts
Originally Posted by Capn Bloggs View Post
The irony, Morno, is that your Flysmart (should) give you a 167% landing distance calculation for dispatch.
It does mate. And for dispatch thatís fine, but Iím sure as shit not going to use 167% while Iím in the air like you said you would.
morno is offline  
Old 5th Sep 2021, 08:26
  #129 (permalink)  
 
Join Date: Jun 2006
Location: 3rd rock from the sun
Posts: 2,146
Likes: 0
Received 0 Likes on 0 Posts
Originally Posted by Capn Bloggs View Post
All I'm saying is that routinely landing with only 15% over the actual landing distance required ie 50ft over the fence to a max-effort full stop, is going to eventually end in grief.
In what aircraft? Are you saying every aircraftís landing performance is predicated on max braking effort? Because youíre very wrong.
morno is offline  
Old 5th Sep 2021, 10:13
  #130 (permalink)  
 
Join Date: Feb 2000
Location: Mycenae
Posts: 494
Likes: 0
Received 0 Likes on 0 Posts
Originally Posted by Capn Bloggs View Post
All I'm saying is that routinely landing with only 15% over the actual landing distance required ie 50ft over the fence to a max-effort full stop, is going to eventually end in grief.
If you only have those landing distance figures available then you shouldnít be using 15%. TALPA arc guidance for aircraft where no inflight landing performance is available suggests using factors of 1.67 to 3.4/5.1 depending on runway contamination and reverse thrust availability.
If a manufacturer has provided inflight landing distance figures, these are not just based on 50ft/max effort so 15% is considered an acceptable buffer.
StudentInDebt is offline  
Old 6th Sep 2021, 02:47
  #131 (permalink)  
 
Join Date: Mar 2002
Location: Seat 0A
Posts: 8,281
Received 0 Likes on 0 Posts
Originally Posted by Morno
And for dispatch that’s fine, but I’m sure as shit not going to use 167% while I’m in the air like you said you would.
And of course, unless you shorten your flight time, you'll always have close to a 67 % buffer when you land anyway...

Originally Posted by Morno
Are you saying every aircraft’s landing performance is predicated on max braking effort? Because you’re very wrong.
What is it based on then?

Originally Posted by Student in Debt
If a manufacturer has provided inflight landing distance figures, these are not just based on 50ft/max effort so 15% is considered an acceptable buffer.
Please explain "not just based on". What are they based on then?

Capn Bloggs is offline  
Old 6th Sep 2021, 03:22
  #132 (permalink)  
 
Join Date: Feb 2000
Location: 500 miles from Chaikhosi, Yogistan
Posts: 4,079
Likes: 0
Received 0 Likes on 0 Posts
50% of headwind for starters.
compressor stall is online now  
Old 6th Sep 2021, 03:34
  #133 (permalink)  
 
Join Date: Mar 2002
Location: Seat 0A
Posts: 8,281
Received 0 Likes on 0 Posts
Originally Posted by Comp Stall
50% of headwind for starters.
If they're based on 50% HW, then when you get there and there's no HW, you're worse off.
Capn Bloggs is offline  
Old 6th Sep 2021, 03:41
  #134 (permalink)  
 
Join Date: Mar 2002
Location: Seat 0A
Posts: 8,281
Received 0 Likes on 0 Posts
A request:

Run Flysmart in the pre-dispatch scenario to say Hamilton Island and advise the landing weight allowed.

Then run Flysmart in the in-flight scenario and advise the weight allowed.
Capn Bloggs is offline  
Old 6th Sep 2021, 03:41
  #135 (permalink)  
 
Join Date: Feb 2000
Location: Mycenae
Posts: 494
Likes: 0
Received 0 Likes on 0 Posts
Originally Posted by Capn Bloggs View Post
What is it based on then?


Please explain "not just based on". What are they based on then?
Youíd have to look that up for your aircraft type, if the information is provided, as it varies depending on the assumptions the manufacturer makes.
StudentInDebt is offline  
Old 6th Sep 2021, 03:45
  #136 (permalink)  
 
Join Date: Mar 2002
Location: Seat 0A
Posts: 8,281
Received 0 Likes on 0 Posts
Originally Posted by Studentindebt
You’d have to look that up for your aircraft type, if the information is provided, as it varies depending on the assumptions the manufacturer makes.
What is it for your type? You don't have to state what type you're on.

Landing is pretty standard: threshold at 50ft at VRef, 7 seconds to touch down then max braking with full reverse to a stop. What other things will make "15% an acceptable buffer" [your words]?
Capn Bloggs is offline  
Old 6th Sep 2021, 04:00
  #137 (permalink)  
 
Join Date: Feb 2000
Location: Mycenae
Posts: 494
Likes: 0
Received 0 Likes on 0 Posts
Originally Posted by Capn Bloggs View Post
What is it for your type? You don't have to state what type you're on.

Landing is pretty standard: threshold at 50ft at VRef, 7 seconds to touch down then max braking with full reverse to a stop. What other things will make "15% an acceptable buffer" [your words]?
50ft, 7 seconds, landing conditions as entered, braking according to chosen method (autobrake/manual-max braking/reverse), reported braking action taken into account. 15% on top of that figure. As the PIC you are free to use whatever figure you like as a buffer if you feel it is appropriate, just as you can opt to use a higher landing minima than say 200ft/550M.
StudentInDebt is offline  
Old 6th Sep 2021, 04:56
  #138 (permalink)  
 
Join Date: Mar 2002
Location: Seat 0A
Posts: 8,281
Received 0 Likes on 0 Posts
Given the thread is about an aeroplane that ran off the end in the wet, your choosing of the desired braking "method" to increase the buffer is irrelevant. Obviously, we're talking about a max-braking landing with only 15% buffer.
Capn Bloggs is offline  
Old 6th Sep 2021, 05:32
  #139 (permalink)  
 
Join Date: Feb 2000
Location: Mycenae
Posts: 494
Likes: 0
Received 0 Likes on 0 Posts
Originally Posted by Capn Bloggs View Post
Given the thread is about an aeroplane that ran off the end in the wet, your choosing of the desired braking "method" to increase the buffer is irrelevant. Obviously, we're talking about a max-braking landing with only 15% buffer.
We are not obviously talking about a max effort stop with a 15% margin because the crew concerned didnít carry out any landing distance calculations. This whole line of conversation has come about because you stated that you donít feel that 15% is an adequate margin on assessed landing performance and prefer to rely on 67/92%.
IFLD figures are there to provide guidance on the actual level of performance available given the conditions and take account of runway condition. So the braking method chosen is not irrelevant, one could calculate the distance required with autobrake 2/low and find that even on a contaminated runway there is sufficient LDA with the 15% margin applied.
StudentInDebt is offline  
Old 6th Sep 2021, 06:08
  #140 (permalink)  
 
Join Date: Mar 2002
Location: Seat 0A
Posts: 8,281
Received 0 Likes on 0 Posts
I am attempting to understand what you people understand about the 15% and why it seems OK on a routine basis, that is all.



Capn Bloggs is offline  

Thread Tools
Search this Thread

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

Copyright © 2022 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.