ZFW...why
Join Date: Mar 1999
Location: Ashbourne Co Meath Ireland
Age: 73
Posts: 470
Likes: 0
Received 0 Likes
on
0 Posts
no sig is right, it's high time airlines, agencies etc get to grips with training and standards.
I would be only too happy to see a much higher skill base in all aspects of ramp handling, it would make for a much safer environment all round, but what level do you set.
I know from experience that Servisair's training covers their equipment, and some very basic fundamentals of how to use it, but there's nothing worth talking about when it comes to type specific information, which can lead to all sort of anomalies, and on occasions, serious damage to aircraft because of lack of knowledge. I've seen ATR's and Dash 8's grounded because a ramp operative didn't know that they needed a current limiting GPU for start. If things that basic are not known, what chance is there on more serious things?
Fortunately, I have other aviation experience, so I had a pretty good idea of the risks, and was able to respond accordingly.
As an example, moving the prop on (say) a completely shut down HS 748 does not present a serious risk to a ramp person. Doing the same thing on a Seneca ( to get access to the forward baggage hold) could be fatal, but nowhere do they cover those sorts of specifics.
There's a bookfull of other things that are similar, but they are ignored, and the end result is people at risk, often because of the ignorance of the management. Ideally, there should be at least one person on each shift that has a high level of aviation experience and training, but the chances of that happening are about the same as pink snow.
Join Date: May 1999
Location: Vancouver, BC.
Posts: 748
Likes: 0
Received 0 Likes
on
0 Posts
Irish Steve
It is true to say that the airlines, particularly the low cost carriers, have screwed down turnarounds costs and that handling standards have fallen. In my previous life I saw a marked increase in ground damage to aircraft, baggage and cargo mis-loading, loadsheet errors which would make you hair curl and generally a dumbing down of the ramp agents (red-caps) skills.
Much of this can be attributed to costs, but I am also of the opinion the centralised load control and computerisation of load sheets has meant that the skills and knowledge once essential to your average ramp agent have all but been lost, not in all cases of course, but in many. I am not against computerised loadsheets, far from it- in fact, if anything these prevented many errors and have increased safety. But with the likes of centralised load control etc. handling agents can save and feel they don't have to train their staff as perhaps they once would. Therein lays the danger IMHO. If an agent airside doesn't possess a sound knowledge base of the principles of aircraft loading and weight & balance = risk increases. You need only look back at some of the UK CAA FODCOMS to understand the concern within the industry over this issue, e.g.
http://www.caa.co.uk/docs/33/FOD200302.PDF
http://www.caa.co.uk/docs/33/FOD200012.pdf
Ramp safety is of course an essential and there is simply no excuse for any employee to ignore their statutory obligations in this respect. Further, the supervision of handling agents by the airline is essential and required by JAROPS1 as we all know.
Training does cost, but it needn't be a high cost and is not optional. The standards required have all been defined by the likes of IATA and ICAO and some UK NVQ's. Further, as the handling company is the agent of the airline, there is no reason why an airline shouldn't define the standards they require- easier said than done however.
It is true to say that the airlines, particularly the low cost carriers, have screwed down turnarounds costs and that handling standards have fallen. In my previous life I saw a marked increase in ground damage to aircraft, baggage and cargo mis-loading, loadsheet errors which would make you hair curl and generally a dumbing down of the ramp agents (red-caps) skills.
Much of this can be attributed to costs, but I am also of the opinion the centralised load control and computerisation of load sheets has meant that the skills and knowledge once essential to your average ramp agent have all but been lost, not in all cases of course, but in many. I am not against computerised loadsheets, far from it- in fact, if anything these prevented many errors and have increased safety. But with the likes of centralised load control etc. handling agents can save and feel they don't have to train their staff as perhaps they once would. Therein lays the danger IMHO. If an agent airside doesn't possess a sound knowledge base of the principles of aircraft loading and weight & balance = risk increases. You need only look back at some of the UK CAA FODCOMS to understand the concern within the industry over this issue, e.g.
http://www.caa.co.uk/docs/33/FOD200302.PDF
http://www.caa.co.uk/docs/33/FOD200012.pdf
Ramp safety is of course an essential and there is simply no excuse for any employee to ignore their statutory obligations in this respect. Further, the supervision of handling agents by the airline is essential and required by JAROPS1 as we all know.
Training does cost, but it needn't be a high cost and is not optional. The standards required have all been defined by the likes of IATA and ICAO and some UK NVQ's. Further, as the handling company is the agent of the airline, there is no reason why an airline shouldn't define the standards they require- easier said than done however.
Last edited by no sig; 13th Apr 2005 at 16:32.
Join Date: Jun 2002
Location: Europe
Posts: 49
Likes: 0
Received 0 Likes
on
0 Posts
Lets start frm basics
Empty Aircraft + Pallets + Pantry = OWE
Also sometimes refered to as DOW
Add Payload ( Pax + Cgo + Crew + Baggage ) you get ZFW
OK I though I was an experienced (Flight Ops) Dispatcher
.. and don't want to sound stupid ... but are you sure that OWE = DOW?
I understand that OWE = Empty mass ...
but for me I would say that DOW = OWE+Crew+Jeppensen+Galley storage+lavatory water+crew baggage (sometimes refered to as BOW)
Empty Aircraft + Pallets + Pantry = OWE
Also sometimes refered to as DOW
Add Payload ( Pax + Cgo + Crew + Baggage ) you get ZFW
OK I though I was an experienced (Flight Ops) Dispatcher
.. and don't want to sound stupid ... but are you sure that OWE = DOW?I understand that OWE = Empty mass ...
but for me I would say that DOW = OWE+Crew+Jeppensen+Galley storage+lavatory water+crew baggage (sometimes refered to as BOW)
Join Date: Feb 2002
Location: don't care
Posts: 3
Likes: 0
Received 0 Likes
on
0 Posts
FEBA is right on both counts:
good explanation of zfw limitation, and
everything else on this thread is a load of bollocks!
Special mention though to Captain 101 - you have certainly established your credentials as a pilot ............. I haven't encountered such complete ignorance in over 20 years in the industry. (perhaps you might like to consider taking along a dog when you fly
)
So as a dipstick check of dispatcher knowledge (or is it a dispatcher check of dipstick knowledge
) ......
who can answer the following:
"when do you need to include fuel in your zero fuel weight?"
good explanation of zfw limitation, and
everything else on this thread is a load of bollocks!
Special mention though to Captain 101 - you have certainly established your credentials as a pilot ............. I haven't encountered such complete ignorance in over 20 years in the industry. (perhaps you might like to consider taking along a dog when you fly
)So as a dipstick check of dispatcher knowledge (or is it a dispatcher check of dipstick knowledge
) ......who can answer the following:
"when do you need to include fuel in your zero fuel weight?"
Join Date: Nov 2004
Location: Dublin, Ireland
Posts: 105
Likes: 0
Received 0 Likes
on
0 Posts
"I find it very alarming the number of dispatchers/load controllers who are unaware of this and are happily packing aircraft full of traffic load before fueling, oblivious to the damage they could be causing to the airframe."
let me interject here for a moment.... when the aircraft is on the ramp, the wings do not produce lift because the a/c aint moving... so my point is what is the problem with loading the a/c before fueling? there is no structural load placed upon the wing root(ok there is gravity
)breaching the zfw while on the ramp will NOT cause damage provided the cargo hold weight limitations are adhered to. The ZFW only comes into play when the wings produce lift.
let me interject here for a moment.... when the aircraft is on the ramp, the wings do not produce lift because the a/c aint moving... so my point is what is the problem with loading the a/c before fueling? there is no structural load placed upon the wing root(ok there is gravity
)breaching the zfw while on the ramp will NOT cause damage provided the cargo hold weight limitations are adhered to. The ZFW only comes into play when the wings produce lift.
Join Date: Jan 2000
Location: Somewhere between here and there....
Posts: 1,232
Likes: 0
Received 0 Likes
on
0 Posts
Lobotumi when it's being carried as ballast or dead weight. BAC1-11's (ah memories) often used fuel "trapped" in the centre tank in order to bring the C of G forward when operating empty. Once at the other end , the crew can then "untrap" the fuel and use it to get home with it's payload.
Join Date: Feb 2002
Location: don't care
Posts: 3
Likes: 0
Received 0 Likes
on
0 Posts
ah Viking9 ... a little knowledge is a dangerous thing.
You are right about the 1-11 but wrong about the rest. After all if the fuel is 'trapped' then you can't use it at the other end can you? Perhaps you area bit confused with a 'short release' (and the subsequent reclaiming of reserve fuel).
'Trapped' fuel is exactly that .. trapped to ensure c of g trim at zfw (not take off weight). This was a particular difficulty of the 1-11 (especially the -300) ... when operating empty .. i.e. (to those in the know) without a 'payload'.
So .. nul points my friend. Back to the ramp for you.
You are right about the 1-11 but wrong about the rest. After all if the fuel is 'trapped' then you can't use it at the other end can you? Perhaps you area bit confused with a 'short release' (and the subsequent reclaiming of reserve fuel).
'Trapped' fuel is exactly that .. trapped to ensure c of g trim at zfw (not take off weight). This was a particular difficulty of the 1-11 (especially the -300) ... when operating empty .. i.e. (to those in the know) without a 'payload'.
So .. nul points my friend. Back to the ramp for you.
Join Date: Jan 2000
Location: Somewhere between here and there....
Posts: 1,232
Likes: 0
Received 0 Likes
on
0 Posts
So how come Monarch, BIA, Dan Air to name a few, carried out that procedure as a standard practice with their -500's ? Maybe my terminology is wrong, but the fuel in the centre tank WAS used for trim purposes on empty sectors !
My days of being on the ramp are long gone my friend...... thank goodness. The job of despatcher at many airlines is not what it once was.
My days of being on the ramp are long gone my friend...... thank goodness. The job of despatcher at many airlines is not what it once was.
Join Date: Oct 2004
Location: UK
Posts: 32
Likes: 0
Received 0 Likes
on
0 Posts
Lobotumi-
A slice of your finest humble pie please!
I'll put my hands up to this one - I was wrong
You cannot damage an aircraft on the ramp by exceeding ZFW -
-Unless you load a low wing aircraft with a very wide main gear span to apx 3 times its Max ramp weight with zero wing fuel providing the fuselage or gear does not break first!!!
I would like to thus submit myself as living evidence of poor dispatch training in the UK along with the fact that my statement went 10 post without being corrected! The MZFW damage on the ground theory was taught to me by a dispatch trainier - I thought is was a little odd that this mode of failure was not mentioned in any of my previous training, but thought nothing of it.
From what i now understand:-
The moment created by the Fuselage weight about the main gear is reduced by the weight of fuel in the wing tank, so on the ramp with zero fuel there IS stress on the wing root - however - the wing root is capable of withstanding stress eqivallent to the aircraft undergoing it's maximum load factor (2.6g+) at MZFW with zero wing fuel. Thats quite extreme and certainly won't happen on the ground!!!
I thus retract the third paragraph of my earlier post with appologies if I mislead anyone.
A slice of your finest humble pie please!
I'll put my hands up to this one - I was wrong
You cannot damage an aircraft on the ramp by exceeding ZFW -
-Unless you load a low wing aircraft with a very wide main gear span to apx 3 times its Max ramp weight with zero wing fuel providing the fuselage or gear does not break first!!!
I would like to thus submit myself as living evidence of poor dispatch training in the UK along with the fact that my statement went 10 post without being corrected! The MZFW damage on the ground theory was taught to me by a dispatch trainier - I thought is was a little odd that this mode of failure was not mentioned in any of my previous training, but thought nothing of it.
From what i now understand:-
The moment created by the Fuselage weight about the main gear is reduced by the weight of fuel in the wing tank, so on the ramp with zero fuel there IS stress on the wing root - however - the wing root is capable of withstanding stress eqivallent to the aircraft undergoing it's maximum load factor (2.6g+) at MZFW with zero wing fuel. Thats quite extreme and certainly won't happen on the ground!!!
I thus retract the third paragraph of my earlier post with appologies if I mislead anyone.
Join Date: May 2003
Location: Tracy Island
Posts: 532
Likes: 0
Received 0 Likes
on
0 Posts
Viking
Don't think so old chap. Centre tank and cofg bear a healthy relationship so the influence on trim by adding fuel to it would be insignificant or very very negligable. In the case of most airliners when empty, ballast is required to improve their handling manners. I think you'll find this is why centre tank fuel was ordered for empty sectors.
As for bollox factor in this thread and the utopian ideals of my mate Nosig (how are you mate?) I note the following:
1) Technical knowledge of things structural ie ZFW and MZFW has led many to utter or pen total bollox. Bollox factor = High
2) The ideals (utopian or otherwise) of qualified or licenced dispatchers most of us share, yet collectively none of us have the balls to take action or do anything about it. My mate Nosig can exclude himself from this criticsm. Bollox factor = low
FEBA
fuel in the centre tank WAS used for trim purposes
As for bollox factor in this thread and the utopian ideals of my mate Nosig (how are you mate?) I note the following:
1) Technical knowledge of things structural ie ZFW and MZFW has led many to utter or pen total bollox. Bollox factor = High
2) The ideals (utopian or otherwise) of qualified or licenced dispatchers most of us share, yet collectively none of us have the balls to take action or do anything about it. My mate Nosig can exclude himself from this criticsm. Bollox factor = low
FEBA
Join Date: Apr 2003
Location: North of CDG
Posts: 1,042
Likes: 0
Received 0 Likes
on
0 Posts
I agree with Maude Charlee and Captain101; and maybe, just maybe, that's why I feel that flight crew are ever so slightly more at ease with me than with some of my colleagues, since I have an ATPL (albeit still "frozen") and therefore the crew know I understand these matters.
We have indeed had an airline rep/station manager ask some of my colleagues what stab trim was, and they couldn't readily answer... I only wish he would ask me
It is true that in some Continental countries, the "Flight Dispatchers" are more actually called "Ground Ops Co-ordinators" and they stay with the a/c during the whole turnaround and are NOT responsible for doing the loadsheets, only for supervising loading etc.
I also agree that the responsibility to explain these definitions clearly is up to the training dept. with your handling agent - a 2-week course is nowhere near enough in this line of work.
Cheers
We have indeed had an airline rep/station manager ask some of my colleagues what stab trim was, and they couldn't readily answer... I only wish he would ask me
It is true that in some Continental countries, the "Flight Dispatchers" are more actually called "Ground Ops Co-ordinators" and they stay with the a/c during the whole turnaround and are NOT responsible for doing the loadsheets, only for supervising loading etc.
I also agree that the responsibility to explain these definitions clearly is up to the training dept. with your handling agent - a 2-week course is nowhere near enough in this line of work.
Cheers
Last edited by FougaMagister; 18th Apr 2005 at 12:32.
Join Date: May 1999
Location: Vancouver, BC.
Posts: 748
Likes: 0
Received 0 Likes
on
0 Posts
You know FEBA it still depresses me that our (UK airline industry) approach to the training of ground and ops staff is so poor and as if we needed any evidence, this post is a good example of the neglect of many of airlines and handling agents.
The only thing I would say to those out there who have not had adequate training is to ask for it- nae demand it, or if that fails go out and do it for yourself. Get the books, do the course, search the web and learn about the job. It need not lead to a Dispatchers licence (although that is a good thing) but do it for yourself. Trust me it will lead to greater job statisfaction and your advancement in the industry.
Learning on the job in our business is simply not enough, you must get the fundemental principles under your belt and the only way to do that is to STUDY. If you haven't got a training course to go to, a good place to start is with the ATPL weight and balance section of the course FougaMagister has done, then you and the crew are operating on the same level.
(FEBA old bean, hope you're well these days)
The only thing I would say to those out there who have not had adequate training is to ask for it- nae demand it, or if that fails go out and do it for yourself. Get the books, do the course, search the web and learn about the job. It need not lead to a Dispatchers licence (although that is a good thing) but do it for yourself. Trust me it will lead to greater job statisfaction and your advancement in the industry.
Learning on the job in our business is simply not enough, you must get the fundemental principles under your belt and the only way to do that is to STUDY. If you haven't got a training course to go to, a good place to start is with the ATPL weight and balance section of the course FougaMagister has done, then you and the crew are operating on the same level.
(FEBA old bean, hope you're well these days)
Join Date: Apr 2002
Location: Abu Dhabi
Age: 44
Posts: 55
Likes: 0
Received 0 Likes
on
0 Posts
Well from reading through the posts, it seems that the only real explanation for calculating the ZFW has been discounted....
I gathered that it was primarily for structural purposes whilst the a/c was on the ground, but there still seems to be the lack of a clear explanation for it...
I gathered that it was primarily for structural purposes whilst the a/c was on the ground, but there still seems to be the lack of a clear explanation for it...
Join Date: May 1999
Location: Vancouver, BC.
Posts: 748
Likes: 0
Received 0 Likes
on
0 Posts
MAN_Dispatcher
Let me have a go.
Put very simply, the maximum zero fuel weight is a structural limitation as defined by the a/c manufacturer. It is defined in the Airplane Flight Manual (for a G registered a/c the AFM is a CAA approved document) which sets out the the procedures for the safe operation of the aircraft. An airline must have a system for ensuring that limiting weights are not exceeded for each flight- in the case of MZFW it is usually by the use of a loadsheet, but can also be by the use of approved on board W&B systems. So, we need to calculate the actual ZFW for each and every flight to ensure we do not exceed the Maximum ZFW.
Let me have a go.
Put very simply, the maximum zero fuel weight is a structural limitation as defined by the a/c manufacturer. It is defined in the Airplane Flight Manual (for a G registered a/c the AFM is a CAA approved document) which sets out the the procedures for the safe operation of the aircraft. An airline must have a system for ensuring that limiting weights are not exceeded for each flight- in the case of MZFW it is usually by the use of a loadsheet, but can also be by the use of approved on board W&B systems. So, we need to calculate the actual ZFW for each and every flight to ensure we do not exceed the Maximum ZFW.
Join Date: Apr 2003
Location: North of CDG
Posts: 1,042
Likes: 0
Received 0 Likes
on
0 Posts
I do agree with no sig, and a good point to start is either to get your hands on the Jeppesen/Oxford Mass & Balance ATPL manual or on the CAA booklet used for the actual ATPL exams - the thin yellow one, can't find it or remember what the CAP no. is! It's quite good for definitions.
In the same vein, it might be of use to follow that up with a Performance manual since a/c perf is dependent on mass and balance (along with other things such as atmospheric pressure, density alt, wind component, runway contamination, bleed air, etc).
Cheers
In the same vein, it might be of use to follow that up with a Performance manual since a/c perf is dependent on mass and balance (along with other things such as atmospheric pressure, density alt, wind component, runway contamination, bleed air, etc).
Cheers
Last edited by FougaMagister; 19th Apr 2005 at 07:53.
Join Date: May 2003
Location: Tracy Island
Posts: 532
Likes: 0
Received 0 Likes
on
0 Posts
Fouga
ZFW is a function of W&B not performance the latter, in terms of weight, concerns itself purely with mass.
To all the other confused of this site with regards to ZFW MZFW whilst the aircraft is on the ground; please consider the following:
Aircraft manufacturers and designers expect their products to spend a good deal of their useful life in the air, not on the ground. Therefor all structural restrictions concern the aircraft in the air and not on the ground (with the exception of max taxi wt, for the picky)
Man dispatcher. You may load your aircraft to the gunnels whilst on the ground without fuel in the wings, they will not fall off. However if you launch your aircraft into the air without fuel in the wings (presumably you're going to tow it into the sky) and you have exceeded the MZFW, then the wings will depart company with the fuselage at the wing root as the lever moment (created by LIFT a product which is not associated with stationary aircraft on the ground) exceeds the design loads.
This must surely be the end of this thread.
Question for the technically minded.
Take off performance - which aircraft achieved V2 before V1?
FEBA
ZFW is a function of W&B not performance the latter, in terms of weight, concerns itself purely with mass.
To all the other confused of this site with regards to ZFW MZFW whilst the aircraft is on the ground; please consider the following:
Aircraft manufacturers and designers expect their products to spend a good deal of their useful life in the air, not on the ground. Therefor all structural restrictions concern the aircraft in the air and not on the ground (with the exception of max taxi wt, for the picky)
Man dispatcher. You may load your aircraft to the gunnels whilst on the ground without fuel in the wings, they will not fall off. However if you launch your aircraft into the air without fuel in the wings (presumably you're going to tow it into the sky) and you have exceeded the MZFW, then the wings will depart company with the fuselage at the wing root as the lever moment (created by LIFT a product which is not associated with stationary aircraft on the ground) exceeds the design loads.
This must surely be the end of this thread.
Question for the technically minded.
Take off performance - which aircraft achieved V2 before V1?
FEBA
Join Date: May 2001
Location: Europe
Posts: 101
Likes: 0
Received 0 Likes
on
0 Posts
itsinthebox,
You should still be able to land with dry tanks - in worst case scenario. Should you be so unlucky to divert to yr alternate, then hold for 30 mins and use your contingency fuel before landing, it would be a sad waste to crash the ac 100 feet from the runway just because of an out of trim situation.
/fs
You should still be able to land with dry tanks - in worst case scenario. Should you be so unlucky to divert to yr alternate, then hold for 30 mins and use your contingency fuel before landing, it would be a sad waste to crash the ac 100 feet from the runway just because of an out of trim situation.
/fs
