Lodsheet Overload?

[NORDIC]

This is not a news item, but anyone who is involved with loadsheets or ops please help!
(Sorry! Title should read Loadsheet Overload)

Take, for example a 757 on a charter flight, carrying 233 pax, and each pax has a suitcase. Some carriers checkin their bags using pieces only (ie number of bags) and use notional weights; As opposed to Pieces and Weight carriers who weigh each bag so an exact load can be obtained. The pieces only carriers are using 13kgs per bag. They are also using standard weights for pax, 88kg for a male, 70 female, 35 child, and anywhere from 0 to 6 for an infant. When the flight closes, and the loadsheet is produced, you have an overload of 30kg. It is decided that you will up your taxi burn from 250 to 280 kgs, because you do not want to depart with an overload, which should be the choice everyone makes.

The question is, How many people on a charter flight do you know whose suitcase weighs 13kgs? At 233 bags each weighing about 20 kg infact, total baggage weight is close to 4.5 - 5 tonnes, whereas using pieces only checkin and notional weights, the loadsheet shows baggage weight is 3 tonnes! The pax weights are closer to the norm for the majority of people, but the difference in baggage weight can be upto double what is shown on the loadsheet.

So why is it that this underload of zero is so critical, and that groundcrews strive to keep everything above board, when really there is another two tonnes of baggage onboard which is not even reflected in the loading? Is this accounted for because I have asked many Despatchers, and nobody knows!

Seeing as though pieces and weight carriers get an exact representation of the load they are carrying, why are all airlines not using this method? Where did 13kgs come from?

In addition, I would be interested to hear from anyone at Air 2000, or JMC who have "Standard Loadings". The trim figure from these loadings on a charter flight tends to be a long way from the ideal trim figure for efficiency, so what is the reason for having these bizzare loadings?

On a 757 with a full passenger load, Hold 3 and hold 4 full with the overspill in Hold 2, it is possible to get the most efficient trim. So why load half and half in 2 and three, or one third and two thirds? What is the logic for this? Obviously there must be answers to these questions, and they are not meant to be attacking in any way at all, but some answers would be appreciated.

The best results always seem to come from Pieces and Weight carriers who allow despatch to aim for the ideal trim.

Anyone any ideas?

Cheers, NORDIC :)


[This message has been edited by NORDIC (edited 10 January 2001).]

[Bus Driver]

Just to add to the confusion, we use 88kgs for a male and 70kgs for a female for scheduled flights but on a charter everyone is 76kgs!
In reality it is just a numbers exercise to keep the CAA happy.

[CargoRat2]

Loadsheets are my balliwack. Thing is I only have Freighter (B742F & B744F) experience. We weigh everything - no guesstimates (well the odd time in some rough places in Africa come to mind :) ).
In general no such thing as saying " Well we have so many big pallets, so many small pallets, therefore the gross weight = X). I've been weighed (+hand baggage) on an LH A321 HAM-MUC before. Its well known that the weights used for pax are a management dream ie b*llsh*t. 80 odd KG for an adult male incl baggage? We use 100KG per crew-member/courier whatever as standard (easy to remember - no difference if male/female/kid). You can only have a guesstimate.
Weigh them all I say!



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rgds Rat

[Mr Benn]

I share some of your concern with loadsheets, but I can't see a quick way round it.
Just to add to the confusion/ facts.
Air 2000 use the figures you mentioned when the flight is a scheduled flight. For charter flights the passengers weights are 83 for a male and 69 for a female.
In the UK I think all the loadsheets show the actual weight of bags. Down route I presume they don't have any equipment to weigh bags so provide purely number of pieces.
Just to make it even more interesting. If its a scheduled flight then scheduled weights are used, but often there may only be a handful of scheduled passengers on board, however all passengers are counted as scheduled for the loadsheet. So we know its pure fantasy figures.
Unless every passenger and bag is weighed we'll never know the true figures. But we don't usually have a huge discrepancy between the loadsheet actual weights and what it would have been if you'd multiplied the number of pieces by 13. From memory luggage is usually around 3000kgs. Of course it does vary depending on the flight and things like ski flights have weights calculated slightly differently.
As for upping the taxi fuel to make the max weights in limits, then why not? As long as you leave with a legal loadsheet then you are OK. You can never know exactly how much weight you have on board.
Of course, if you are severely limited, on a short runway with terrain problems, or something else to consider then it becomes particularly important to ensure you are not overweight.
As for Air 2000 trim on the 757, I don't know why the policy is there, all I can think is it may be something to do with the policy Air 2000 has of trying to make the Boeing and Airbus operations as similar as possible.

[Flying_Steph]

I'll always remember that incredible flight where the Chief Flight Engineer (that mthrfckr's supposed to show the good example, right ?) did two loadsheets: one for the records and the CAA, and another one to know the approximate overload and trim setting.
Anyway... :rolleyes:

Under JAR-OPS rules, the standard weight of the bags depends on the type of flight.
-Domestic: 11 kg
-Within the UE: 13 kg
-Intecontinental: 15 kg
-All other: 13 kg

If an operator does not want to follow these standard masses, he has to advise the CAA of his reasons and gain its approval in advance. He must also submit for approval a detailed weighing survey plan and apply the statistical analysis method given in the JAR-OPS Appendix & IEM 1.620 where they throw formulas all over the place to estimate the pax & baggage weight. If the revised standard masses exceed those given in the JAR-OPS, the higher values must be used.
And if on any flight the standard masses (pax and/or bags) are expected to be exceeded, the operator must determine the actual mass.

For info, the weight of a male pax varies from 83 to 104 kg depending on the type of flight (JAR-OPS).
Things aren't always easy unfortunately.

[NORDIC]

After Captain or FO calls the traffic office to obtain an EZFW and pass an RTOW due to wx or other, hence flight is limited weightwise, you may be handed a loadsheet which reflects a zero underload. You have no more weight available, or so the figures say, due to the RTOW. So when this loading is calculated using 13kgs per bag, but everyone checks in a bag weighing 20kgs, and the flight departs, this seems to reflect that the loadsheet is a paper formality which is not as critical as it may seem. Yes, the max weights etc have to be adhered to, and some means of calculation is required but just how is this justified when your MTOW is say 70 tonnes, the loadsheet says you are at MTOW, but really there is another tonne or so weight in the back which is not seen on paper? Are the figures compensated for? If so, I would be interested to know just how many 'heavier than stated' bags would be loaded before the loadsheet was perfectly in line with regs, but there was an accident due to too high an overload! Maybe I am missing something, but this is a question which has been asked in load control training, and any further feedback would be appreciated to pass on to a despatch trainer who I know!

Cheers guys for your responses so far!
Fly safe, and stay within limits!

NORDIC :)

[astrocyte]

It is never critical provided all the engines keep going!

[mallard]

Regarding the less than ideal trim of loading bags on the 757 in holds 2 and 3 may I suggest it is to get a quicker turn-round as you have two crews loading two hold doors rather than one crew trying to get 200+ bags through one door into holds 3 and 4.
And yes, when I go on holiday my case is closer to 20 kg than 13. Multiply that by the capacity of the aeroplane and I guess your average charter jet is overweight.

[Juliet November]

I'm sure what the purpose of this thread is about, but there are several ways of legally getting around an overload in a tight situation. However, not all options are open to all airlines, depending on their internal policy and, even more so, the willingness of the flight deck crew to accept the "creative book keeping" offered by the loadcontroller / dispatcher.

Regarding baggage weight. Handling agent I used to work for weighed in all baggage, but some of the airlines we handled would accept a standard weight per piece regardless. So, if you have an overload and find that the average weight per piece exceeds 13 kgs, simply mulitply the number of pieces by 13 to get an incorret but legal weight. That should get you parts of the way. If still overloaded, it is also for some airlines legal to presume that the carry-on baggage weight has been included in the scaled weight. Far fetched, but still legal. So multiply total pax count by 5 kgs and deduct from baggage weight. Now we're down to each pax having only 8 kgs of baggage with them, which is clearly a huge understatement but never the less legal.

These days I'm working with freighters only (thank god, no more pax !) and everything is scaled leaving no room to be creative with anything but fuelburn. Depending on whether you're restricted by TOW or LW you may try to convince the crew to burn a little extra on the taxi or trip fuel. But generally there's not a whole lot to be gained here.

Finally, before turning over a "creative" loadsheet to the crew, make sure they understand what has been done and why. After all, they are the ones taking your loadsheet to the skies and not you.

Why take these steps ? Because all loadsheets today are computer generated. In the good old days with paper and pen, you could "bend" a straight line to suit your needs or make some creative adjustments to the weights. All with the goodwill of the crew of course, but most crews are as interested as ground ops to get all pax / freight / mail onboard in order to generate a turnover for the company. It's business, not personal.

But the key here is to keep the flightcrew in the loop, so to speak. Failing to do so can have you facing a very irrate captain insisting on a loadsheet reflecting reality and nothing else. Keeping them informed, they'll understand the situation and will probably let you get away with quite a lot.

An instructor once told me (on another subject though) "It's allright to cheat, as long as you know what you're doing and what the implications are for all involved".

As to standard loadplans vs optimum trim. Well, I guess it's a fight over what's most important: Maybe the focus is on securing a tight turn-around and on-time performance, maybe it's on saving fuel, or maybe it's about maximizing the capacity in order to carry all bags / freight / mail etc. However, it's only during cruise that a tailheavy trim will save any fuel, so on a short sector with little cruise time, the fuel saved by a "perfect" trim may be wasted if you are late on the departure, or if you are leaving behind revenue earning payload.

[Icarus]

Procedures are laid down on how to statistically determine weights for passengers and baggage. These procedures are published by IATA/ICAO and JAR OPS.
They produce weights that fall within a 2% confidence range for passengers and 1% confidence range for bags.
This effectively means that the actual weight of every bag on your aircraft is likely to be at the standard weight or somewhere between -1% and +1% of the standard weight.
The same applies to passenger weights.
..
{If as you say your weights mean a big diffence between actual/atandard then you company has a problem! Do you notice performace deviations to justify this? Green dot speeds and altitudes not being attained?}
..
Which means that the figures you see on the loadsheet for passengers and baggage are about as accurate as you can get (without weighing everyone and each bag separately)which still happens on small aircraft.
Figures differ carrier by carrier if they elect to survey their own passengers/baggage as opposed to adopting those figures presecried by their CAA/DGCA.
However, a carrier must adopt only one set of figures for use on all its flights and cannot mix actual/standard weights on a flight. Special circumstances may void standard weights such as large gruops of particualr traffic - military/sports people etc.
Dont forget that the SG of your fuel will and does differ day by day region by region, yet the loadsheet will probably be based on 0.8kg/L only and this will mean the weight shown is correct, however due to increased volume or decreased volume of the fuel in tanks your trim data will perhaps not be as accurate as possible.
Some EDP systems have multiple fuel tables for other then your elected standard SG and can get round this (most dont!) and manual documents will be based on only one SG.

The only thing you guys need to worry about is the competence of the guy and/or system calculating the weight and balance.

[This message has been edited by Icarus (edited 11 January 2001).]

[Icarus]

Nordic - sorry, missed the bit about standard loadings. THERE IS NO SUCH THING! In theory anyway, practice there is as it makes life easy.
However, as Chairman Mao once said - People should raise their level of practice to that of the theory, not lower the theory to the level of practice!.
A company may issue standard loadings but htese really date back to the older days when we didnt have such accurate EDP systems which will trim passengers by each seat row rather than by an individual cabin area, allowing for the load controller to utilise his brain and load the deadload to give better trim (which is aft biased for fuel economy rather than foward biased for stability). On a full load yes/maybe a standard loading may apply, but come down from that and they do not! Even if you have even passenger distribution upstairs at whatever pax count you have does not mean baggage is stilled stowed as per the standard. I had this once (long time ago with an Orion B733 Capt.): It wasnt a full load nor were passengers distributed evenly (still smoking seats then etc.) so I had to load bagage non standard to trim the aircraft. On the ramp he saw this and changed the loading to standard and distributed the pax on board evenly. He didnt tell anyone. Anyway I found out after he was airborne and did the recalculations, regardless to say - he was out of trim at ZFW. OK at TOW/LAW. Who cares - well the aircraft hull does of course as it is now under stresses it wasnt designed for!

Once a loadcontroller/despatcher and load control instuctor, I am now responsible for Load Control policy and airport systems for a flag carrier in a region that employs the cheapest labour possible for this type of work; like I said before, you just need confidence in the guy/girl giving you the loadsheet to have ensured it reflects your actual loading, just as much as the figures on it (which are OK as I explained above) - unless its a manual loadsheet; then I would look pretty damn close if I were you!!

As for pcs/wt carriers giving you a better trim - not quite true! They only weighed the baggage at check-in not on the belt going up to the hold; they then calculated an average bag wt at the aircraft side and that average bag wt was used to determine your hold load! And beleive me, that figure will not be as accurate as using a correctly determined standard weight!!


[This message has been edited by Icarus (edited 11 January 2001).]

[Buster Hyman]

Fully agree with Icarus there Nordic.

Having done Weight & Balance for Pax & Freighters for many years, I get annoyed with the inacurracies as well. Even on the widebodied aircraft with Pcs/Wgt check in, you may assume that a full can weighs 800 or so Kg, but volume then comes into play & who knows what's in a can full of volumetric articles. One thing I'm certain of, your bosses will NEVER put in writing anything that would exempt you from fault where an incident occurs BECAUSE of an inaccurate Loadsheet. I've tried for years to get anything from my company as to my liabilities in the matter, but, to no avail.

If it is something that concerns you, all I can suggest is to have the cans weighed (or barrows for narrowbody). Yes, it's a pain in the ar$e, but I know a bigger pain. BTW. Aircraft like the 744's tell the crew how much the aircraft weighs on the stand & it's trim as well, so I think the failsafes are well & truly being developed to alleviate this problem.

Remember; it's not the accuracy of the trim, it's the thickness of the pencil!

[peewun]

I spoke to a very senior management pilot about this situation and he said that the CAA were aware of it and were happy with the way things were being done(commercial pressure?). Question is, how much margin for error is there in the performance manual when talking about weights. Things are fine when both engines keep going during the take - off but what happens when it goes quiet on one side just before V1, at max take off mass (as far as the loadsheet is concerned) when in actual fact, in a 200 seat aircraft we are 200 x 7kgs overweight. Now I am no engineer but the kinetic energy of 1.4tonnes travelling at 150kts, I assume, would convert into a fair deal of extra heat energy on brake application. Are the brakes up to the job? It would be interesting to get an engineers expert view on this matter or an expert in performance calculation.

[4dogs]

Folks,

Surely the discussion is about theory versus acceptable commercial practice.

While I note the pejorative comment about "commercial pressure", the reality of sound regulation is recognising the potential for Catch 22 rules that set an unachievable benchmark for practical commercial operations. That is why we have a lot of so-called "despatch" rules (our planning rules) and their often less stringent cousins, the "operating" rules.

The aim of all of our loading rules is to operate the aircraft within certain limits. If we require an operator to weigh every passenger and every piece of baggage and to adjust the fuel weight for the tested SG by the actual temperature of the tanks, the ambient temperature and the delivery temperature so that it can be matched by the performance calculated for the average air temperature at the engine inlet height for the wind and circulation over the unshaded runway surface, corrected for the actual lapse rate for each obstacle clearance altitude, not forgetting the need for realtime analysis of actual wind velocity at every point of the departure flight path until clear of obstacles which, when modified by the performance decrement attributable to the handling pilot's control technique and accuracy.....etc, etc, we are never going to move another aeroplane again - anywhere!!

So we must compromise. We conduct statistical analyses of all sorts of things and we make regulatory (and commercial) decisions about acceptable risks. We survey passengers and we survey their baggage for weight profiles. We strike a figure, let us say 85%, and we come up with a weight for the individual (or the cabin baggage, checked baggage or nursed infants) that on 85% of occasions will be equal or greater than their actual weight. Then we analyse those individuals in various populations appropriate to the aircraft seating capacity to make sure that we have an appropriately low probability (say 10^-4) that the population actual weight will exceed the population standard weight. Note that in Australia, this sort of population analysis is what led to the increases in recommended standard weights for the smaller aircraft and the recommendation against standard weights in the common piston twins. And while we are at it, let us make the operator responsible for making appropriate adjustments for special charters or operations where the passenger complement clearly is not the normal distribution (mining sites, holiday charters, the world weight-lifting championships, etc).

Now we can plan the load and have the chance of despatching the aircraft in fairly quick time, knowing that the time and inconvenience saved by not weighing everything and everyone has an acceptably low risk of exceeding aircraft limits. All in all, a practical compromise that let's us move people and things with a modicum of efficiency.

Now, for all of you who report obvious failures to use realistic weights, make a stand to satisfy yourself that you are operating safely - there is no loyalty and no reward for overloading, just a lot of loneliness when you get caught or someone gets hurt. You don't have to fall on your sword - there are ways to get both your management and, if necessary, the regulator to act without becoming unemployed.

Aviation is full of compromises - just make sure that they don't get corrupted by ignorance or greed.

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Stay Alive,

[email protected]

[Out Of Trim]

As a current Load Controller/Despatcher at LGW; I agree with much of the above.. there is a compromise as much in life. Most airlines dictate a "standard Full trim" ie. say B757 with 233 pax and average 1 bag per pax at notional weight 13kgs. To enable a fast turnround - holds 2 and 3 would usually be utilised at approx 1/3 and 2/3 to enable both holds to be loaded at the same time.
Quite usual trim is 70 bags hold 2, next 150 bags hold 3 and remainder hold 4. These trims are usually based on the booked pax figure long before the flight closes and is subject to ammendment at flight closure - at minus 40 mins when probably at least half the bags are already loaded.

It generally gives an acceptable trim efficency wise but probably nowhere near optimum; but allows some flexibility - If pax load drops off from the booked figure then it probably wont cause any trim problem on a 757 but Airbus 320/321 is another story.. It generally necessitates moving pax in the cabin rearwards for trim. Of course we have the optimum trim in mind at all times and strive to achieve the best possible without causing a delay.

As to the overweight debate.. I find that when looking at the baggage being loaded - OK many will be more than 13 kgs but also many quite a lot less - so probably averages out to be fairly close and performance figures allow a wide margin to cater for this.



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<font face="Verdana, Arial, Helvetica" size="2">Happiness.. is being IN Trim!</font>

[Icarus]

The original post asked certain questions, concisely, I believe the answers are as follows:
1. Probably no bags weigh exactly the standard weight. However, the total actual weight of all the bags loaded will be very close to as if they did. The statistically determined standard weight will normally mean 95% of all the bags loaded will have a weight somewhere between +/-1% of the standard. As the survey will have resulted in a normal population distribution curve (bell shaped), this means that there will be fewer and fewer instances of bags weighing much larger or much lesser than this.
Hence you can be confident that the actual weight will in fact be very close (tolerably close) to as if they all weighed the standard weight. http://www.pprune.org/ubb/NonCGI/confused.gif
2. The zero underload is critical simply because you CANNOT LEGALLY depart overloaded!! :)
3. Standard loadings are nonsense for the reasons previously published. http://www.pprune.org/ubb/NonCGI/tongue.gif

(OUT OF TRIM - How can you tell if a bag weighs a certain amount just by looking at it! Surely you have to pick it up and then you can only guess! And then I bet you would be at 10-15% out with your guess).

Happiness appears to be flying out of somewhere other than LGW!!

[This message has been edited by Icarus (edited 13 January 2001).]

[Buster Hyman]

Standard Loads? I once did a "test" on a 762 with a colleague from another port where standard loads were the norm. I blew his figures out of the water with my "optimum" trim and he treated me like I'd cheated!

Our job is to safely & efficiently load the aircraft, nothing more, nothing less. If the rules we work under are suspect, I guess you go to another job, especially if you are unhappy with those conditions....I did.

[Out Of Trim]

Icarus - I agree that you cannot tell the weight of a bag just by looking at it - I was merely trying to point out that on most flights that not all bags are average - some will be large and heavy and some will be smaller and lighter. In my experience large hard shell cases are usually heavier than the smaller soft types and these are both usually heavier than small holdall bags.. Not that you would use that as a basis for determining the actual weight.

As for your dislike of standard trims - Well I'm sorry - but it works very well for the Charter Flights - usually full in Summer with quick turnrounds a necessity for the three or four rotations of these aircraft.

However, at other times, when flights are not full I agree there can never be a "Standard Trim" and we will block seat rows in the cabin if necessary and adjust the baggage loading accordingly to get as close to optimum trim as possible. :)

[Icarus]

So now we have 'Standard Trims' as well as standard loadings?
Agreed a 'normal' loading based on pre-disposed conditions (full load upstairs)can result in a quicker turn-around for some aircraft types. :)
However, if you are loading both ends anyway then you still have the same amount of bags going up two belts hence a non-standard loading will take just as long or short a time. :)
If your loading only one end it doesn't matter.
Restricting passenger seating (and/or up/down grading on schedules)should be a last resort under any circumstances (if it is used any earlier I see that as not doing one's best http://www.pprune.org/ubb/NonCGI/frown.gif - sorry) and a deviation from a pre-ordained loading instruction a better option. http://www.pprune.org/ubb/NonCGI/redface.gif