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

Runway behind you.

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

Runway behind you.

Old 16th Jul 2009, 18:52
  #21 (permalink)  
 
Join Date: Jul 2008
Location: Gone to my "Happy Place".
Posts: 157
Likes: 0
Received 0 Likes on 0 Posts
Cool

Educated and / or common sense reply's. Excellent, where were all you guys when we were debating enroute alternates?
Jimmy Do Little is offline  
Old 16th Jul 2009, 19:14
  #22 (permalink)  
 
Join Date: Jun 2001
Location: Boldly going where no split infinitive has gone before..
Posts: 4,781
Received 44 Likes on 20 Posts
Excellent, where were all you guys when we were debating enroute alternates?
Which I've noticed you've stopped doing since you were shown you didn't know what you were talking about
Wizofoz is online now  
Old 16th Jul 2009, 19:58
  #23 (permalink)  
Warning Toxic!
Disgusted of Tunbridge
 
Join Date: Jan 2005
Location: Hampshire, UK
Posts: 4,011
Likes: 0
Received 0 Likes on 0 Posts
Don't talk about thrust! When some of these people discover we never use full power on take-off, it will unleash the hounds out of hell!
Rainboe is offline  
Old 16th Jul 2009, 20:21
  #24 (permalink)  
 
Join Date: Dec 2006
Location: The No Transgression Zone
Posts: 2,483
Received 5 Likes on 3 Posts
firstly all the writings about FAR 25 and performance A is not relevant to this poster's query as everyone here knows just how completely diffrent the certification criteria are.

I don't know about there in the UK, but here in the US under the FARs the pilot in command is directly responsible for and is the sole authority as to those sorts of decisions...but if you make that decision,...may have other consequences, for example, to wait forever and burn lots of fuel etc. perhaps upset a few folks, get laughed at, derisive comments --all to be ignored once you've made your decision but the decision shouldn't be made in an ignorant manner...e.g.


but in a SE or far 23 twin you have to evaluate the two options if the surrounding terrain is unfriendly,... it may be worth the wait,...if however you have a 10000' RWY at a busy class B terminal then perhaps the wait is not worth it

PA
Pugilistic Animus is offline  
Old 17th Jul 2009, 11:02
  #25 (permalink)  
 
Join Date: Jul 2008
Location: Gone to my "Happy Place".
Posts: 157
Likes: 0
Received 0 Likes on 0 Posts
Runway behind you IS useless because you can't use it. Simple as that.
V1 is V1. A longer runway will effect your performance calculations, but regardless, once you've hit V1 (just prior), your going flying (or should be)!

Another way of looking at it is this....

Specific Runway is 10,000 feet long. If your aircraft was quite light (Ferry flight for example) you''ll be airborne in less than 4000 feet. Once you've hit your computed V1, you fly. Now the runway ahead of you in useless, since chopping the power (Most Boeing, Airbus and Douglas) and landing straight ahead is not an option.

Granted, during an RTO at heavier weights, that intersection departure may leave you wishing that you'd gone the full length. However - had you - you could have possibly computed a higher V1 speed anyways, so in the end, it's all pretty much the same.

Last edited by Jimmy Do Little; 17th Jul 2009 at 11:49.
Jimmy Do Little is offline  
Old 17th Jul 2009, 11:17
  #26 (permalink)  
 
Join Date: Jul 2008
Location: Gone to my "Happy Place".
Posts: 157
Likes: 0
Received 0 Likes on 0 Posts
Which I've noticed you've stopped doing since you were shown you didn't know what you were talking about
Some of us actually work for a living.

I might suggest that you have a look at the "Tech Log" forum rules... (Some examples follow)...

Tech Log is not ...
(a) an academic ivory tower with information being rigorously correct and subject to strict peer review.

(b) an idealistic think tank.

(c) available for, or of use only for, experienced Industry people. We want all PPRuNe people to use this forum and know that they are welcome and welcomed here. You will find here Industry beginners right through the whole range to the most experienced of Aviation, related Industry and academic personnel.

(a) abuse of another poster will not be tolerated at all ... play the ball hard by all means if the subject matter is controversial .. but NEVER the player. In using the term "abuse", we include anything of a nasty nature... including overt sarcasm, vilification, etc., etc. .. Please remember that a poster may be very new to the Industry and not have as much knowledge as more experienced people .. the aim is to spread the knowledge base amongst all who might have an interest in learning. This is not to suggest that friendly banter is not welcome .. I am sure that we all understand what is being suggested here ...

(b) it is an Industry truism that, if you ask 10 pilots (engineers/ATC-ers/FAs etc., etc.) a complex question, you will probably get 20 different answers. Sometimes a slightly different approach to an answer will make just that little bit of difference to your understanding the subject material ... we all learn and understand in slightly differing ways ..

(e) if you are posting an answer, please qualify your comments where appropriate, e.g., "on the such-and-such aircraft", "in my airline", "under British rules", etc. Sometimes, useful and detailed comments are rendered unusable if the reader doesn't know the context.

Maybe a moderator could elaborate further.





firstly all the writings about FAR 25 and performance A is not relevant to this poster's query as everyone here knows just how completely diffrent the certification criteria are.
I'll agree with that. Where I previously wrote FAR/JAR 25..., insert "Transport Catagory Aircraft with certified engine-out climb performance." Also agree - as previously stated - that it's not relevent to a typical PPL.

Last edited by Jimmy Do Little; 17th Jul 2009 at 12:05.
Jimmy Do Little is offline  
Old 17th Jul 2009, 16:52
  #27 (permalink)  
Moderator
 
Join Date: Apr 2001
Location: various places .....
Posts: 7,173
Received 92 Likes on 61 Posts
Which I've noticed you've stopped doing since you were shown you didn't know what you were talking about

We're all big people and have broad shoulders. Hence a bit of latitude is reasonable... however the above comment is about as far as we would like it to go in Tech Log.

If we were to be excessively PC, then we would not get very far in our discussions ...
john_tullamarine is offline  
Old 17th Jul 2009, 17:01
  #28 (permalink)  
VC9
 
Join Date: Oct 2004
Location: Australia
Posts: 71
Likes: 0
Received 0 Likes on 0 Posts
What really irritates is when a "Airmanship" is used as an excuse for ignorance. Unfortunately I have experienced this often in my forty something years as a military/airline pilot.
VC9 is offline  
Old 17th Jul 2009, 17:27
  #29 (permalink)  
 
Join Date: May 2009
Location: United Kingdom
Age: 62
Posts: 212
Likes: 0
Received 0 Likes on 0 Posts
The lighter perspective.

I am just a humble light twin PPL and am interested to see the points of view outlined here.

One understands why a commercial set up would like to expedite departure (fuel saving, time savings, slot availabillity) and with all the thrust available to modern jets it is clear that this the sensible approach.

One earlier poster mentioned Manchester and the light stuff being in synch with the big commercial traffic. I used to fly out of Cardiff and would accept an intermediate hold point and departure if the numbers clearly indicated that I had more than enough margin to get up and away safely within the regs (never a problem there).

However I still feel better if I know that I have enough runway to land straight ahead and preferably still come to a stop if something goes bang on take off. The margin between climbing on one engine and descending in what I fly is often very small and without the luxury of all that additional thrust, runway ahead is not to be sneered at.
Cacophonix is offline  
Old 17th Jul 2009, 21:00
  #30 (permalink)  
 
Join Date: Jun 2009
Location: Tunisia
Age: 71
Posts: 146
Likes: 0
Received 0 Likes on 0 Posts
3 things will get you in this business
1. runway behind you
2. fuel in the truck
3. flight attendant with a chipped tooth
poina is offline  
Old 18th Jul 2009, 00:13
  #31 (permalink)  
 
Join Date: Jul 2009
Location: N 06/W 75
Posts: 81
Likes: 0
Received 0 Likes on 0 Posts
Another way of looking at it is this....

Specific Runway is 10,000 feet long. If your aircraft was quite light (Ferry flight for example) you''ll be airborne in less than 4000 feet. Once you've hit your computed V1, you fly. Now the runway ahead of you in useless, since chopping the power (Most Boeing, Airbus and Douglas) and landing straight ahead is not an option.
Me thinks "Who cares?", since you are already up, even in the most precarious situation from a performance point of view (i.e. engine-out), you are expected at least not to descend any further; and that "old saying" is pretty much of the single-engine pilots, because for them those little meters you just left behind could prove to be of life and death.

Just my 2 cents. Not to offend you, nor anybody else.

Last edited by Ocampo; 18th Jul 2009 at 06:11.
Ocampo is offline  
Old 18th Jul 2009, 00:31
  #32 (permalink)  
 
Join Date: Nov 2007
Location: United Kingdom
Age: 71
Posts: 713
Likes: 0
Received 0 Likes on 0 Posts
NamibFox,

You're quite right, it would be great to know if we could land straight-ahead; however, like most twin-engined aeroplanes, a failure of one engine will most likely mean that we'll be committed to an unscheduled landing into a suitable vacant space within the countryside... that's a fact! Unless of course that you're flying for fun and that you're not carrying an appreciable payload; otherwise, we might fly the curvature of the earth and find a suitable route back to where we defied the original effects of gravity!

Ho-hum,

TCF
TheChitterneFlyer is offline  
Old 18th Jul 2009, 09:12
  #33 (permalink)  
 
Join Date: Jul 2008
Location: Gone to my "Happy Place".
Posts: 157
Likes: 0
Received 0 Likes on 0 Posts
Me thinks "Who cares?", since you are already up, even in the most precarious situation from a performance point of view (i.e. engine-out), you are expected at least not to descend any further; and that "old saying" is pretty much of the single-engine pilots, because for them those little meters you just left behind could prove to be of life and death.

Just my 2 cents. Not to offend you, nor anybody else
No offence taken. For the SE guys (Or even some smaller ME), you're entirely correct. Point is, that in larger ME aircraft, performance is calculated, and provided that you calaculate correctly (EK Tailstrike comes to mind), it doesn't much matter where on the runway you start from so long as you've calculated from that point - generally speaking of course.
Jimmy Do Little is offline  
Old 18th Jul 2009, 10:03
  #34 (permalink)  
 
Join Date: Feb 2009
Location: some hotel
Posts: 69
Likes: 0
Received 0 Likes on 0 Posts
runway behind

A person once told me there are 4 things useless to a pilot;

- runway behind,
- fuel in the truck,
- altitude above and
- a birthcontrol pill in your pregnant wife's hand.

Respecting all philosophies and practices on fuel saving, balanced field T/O etc. etc. the statement on the uselessness of these things when present remains valid.
Does that mean all procedures are wrong and need to be changed? No.
Does it hurt to depart full length when available? No.

Maximising profit and time available does not take place during intersection take-offs or departing minimum fuel when indexes are similar. It takes place during the organisation of a controlled turnaround and the execution of it. For scheduled operations that is. There is a difference between what is wise and what is permissible. A clear example of that is work and rest regulations. Don't hear many folks that suffer from the "hurry-up-time-is-money" syndrom advocate that though .

The same applies for speed control on final but that is off topic.

Cheers.
postman23 is offline  
Old 18th Jul 2009, 10:25
  #35 (permalink)  
 
Join Date: Jul 2005
Location: エリア88
Posts: 1,031
Likes: 0
Received 0 Likes on 0 Posts
I'll be more than happy to take-off with max thrust, max fuel and use full length, when the passengers are happy to pay the full cost in fares to cover the substantial increase in operating costs.

Mercenary Pilot is offline  
Old 18th Jul 2009, 17:13
  #36 (permalink)  
 
Join Date: Jul 2009
Location: N 06/W 75
Posts: 81
Likes: 0
Received 0 Likes on 0 Posts
Don't hear many folks that suffer from the "hurry-up-time-is-money" syndrom advocate that though .
Actually, it's not a syndrom, I'd say it's more like a culture that you learn when you are up in an airliner. Couple of examples that comes to my mind is doing rolling takeoffs; that stopping and further acceleration of the engines is worth a few pounds of fuel (specially in older jet engines). You accept or request any "direct-to" that suits your needs, you try your best not to enter a holding pattern unless it is that necessary, for whatever reason it is, and if you do enter the holding pattern, then you descend as much as you can within permissible limits to not waste a whole lotta time, time equals fuel, fuel equals money for your company.

I'll be more than happy to take-off with max thrust, max fuel and use full length, when the passengers are happy to pay the full cost in fares to cover the substantial increase in operating costs.
I second that!
Ocampo is offline  
Old 18th Jul 2009, 18:06
  #37 (permalink)  
 
Join Date: Oct 2005
Location: USA
Posts: 3,218
Likes: 0
Received 0 Likes on 0 Posts
One must consider the aircraft, the circumstances, the load, the runway conditions, the predicted performance, and the type of operation. In many operations, it's very wise to use all the runway. In others, especially operations in which one will have no difficulty remaining aloft following an engine failure, then runway behind isn't particularly relevant if adequate runway to stop or go lies ahead.

One must certainly differentiate between transport category aircraft, and everything else, but one must also look at other circumstances. Can the aircraft depart safely, using predicted and calculated performance, from the current intersection? If I need nine thousand feet to stop or go and there are fourteen thousand remaining, then I've certaily got more than enough. Taxiing the fulll length may create unnecessary ground handling problems or delays, may increase tire temperatures unnecessarily, and may mean an extended wait due to traffic which isn't warranted when the takeoff can safely be done from the intersection.

That said, all else being equal, I'll take full length whenever I can get it.
SNS3Guppy is offline  
Old 19th Jul 2009, 08:47
  #38 (permalink)  
 
Join Date: Feb 2009
Location: some hotel
Posts: 69
Likes: 0
Received 0 Likes on 0 Posts
Well spoken Guppy, although I do not have the tire temp issue on my dinky little jet.

The preceeding 2 replies indicate to me that more people prefer full length when available. The point I was trying to make is that there is always going to be some beancounter who thinks some modification of an existing practice will generate additional revenue, whether that will be through fuel or taxi time or duty regulations optimisation.
In the end that extra cash will not land in your lap, if it is actually generated in the first place. Traditionally it is used to downsize the budget for the following year, which in return requires alteration of yet another practice. Scrapping crew meals for example. In my previous operation, it became close to mandatory to accept intersection take-offs for 'traffic reasons'. Nobody bothered to think about the fact that we (medium category) now needed 3 mins after a heavy departure from the full length.
Long story short: most of the time we ended up idling at the intersection for an additional some mins to accomodate other traffic. Where is the logic in that?

Pilots are go-minded people with ridiculous levels of flexibility. Under the header of "Yes it can be done" this industry has seen erosion of sensible practices for no truly valid reasons. With all respect; if an airline's survival depends on whether they depart from an intersection or taxi out an extra 30 seconds, I think their financial pressure is beyond healthy.

My 2cts anyway.
postman23 is offline  
Old 20th Jul 2009, 20:30
  #39 (permalink)  
 
Join Date: Dec 2006
Location: The No Transgression Zone
Posts: 2,483
Received 5 Likes on 3 Posts
Sheesh I'm doing terrible these days or is this thread a repeat?

I don't seem to be reading

I guess it best to continue my silence these days
sorry everyone--it's been a contentious time to say the least--- and I'm not in my best mind set--for aviation
PA

Edit: although when this period passes I'll surely be the the one better off and maybe I can even buy an Eclipse jet or something cute like that,...but in the mean while

then I can once again talk sensibly on Pprune

CAVU everyone


If the offending parties even read Pprune, though I doubt it, [comment here deleted for bad form by PA] but these folks ain't no pilots for sure,...anyways

Lester

Last edited by Pugilistic Animus; 21st Jul 2009 at 23:35.
Pugilistic Animus is offline  
Old 7th Aug 2009, 18:17
  #40 (permalink)  
 
Join Date: Dec 2006
Location: The No Transgression Zone
Posts: 2,483
Received 5 Likes on 3 Posts
I forgot to mention this---- but it is advisable for the more limited aircraft [far23] departing VFR to request, if available of course, a Right or Left downwind departure so as to be in a good position to get back to the runway if needed in a pinch

PA
Pugilistic Animus is offline  

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.