Weight and Balance, Form and Function

Do we have to? Weight and balance? Could anything be more boring?

Actually, yes, quite a few things are more boring than weight and balance. The guest book at any B & B, for instance: “Loved it! Can’t wait to come back! And the bran muffins—delish! And those charming people from Montana! Who would have known there was so much to know about macramé!” As Charlie Brown would say, “Ahhhhhhhhhhhh…!”

In aviation, the most boring subject I know, one which general aviation pilots are normally spared but no commercial pilot ever makes a clean escape from, is the annual, mandatory “hazmat” training—hazard materials. It didn’t make any difference in our case that the ATA General Operating Manual—The GOM, “The Law”—stated very clearly that, “ATA will not transport hazardous materials,” we had to sit through it every year anyway. Weight and balance is practically exciting compared to that. And at least it has relevance for all pilots of all aircraft. But why does it have to be so difficult and tedious? Isn’t there some way to make it simple? And halfway interesting?

“Simple” may be a stretch, but a lot simpler is certainly possible. And halfway interesting ought to be possible once an important aspect of weight and balance is understood: the importance of weight and balance is directly proportional to the complexity of the aircraft. If you want to fly fancy airplanes, you better be ready to deal with weight and balance. It’s pretty hard to get a Cessna 150 out of balance, for instance: there are only two seats, side by side, with a limited baggage area behind them. As long as you observe the weight limits, the balance will pretty much take care of itself. But as soon as you start adding rows of seats and external baggage compartments, the complexity begins. And it gets really complex when you sweep the wings and put the fuel in both center and wing tanks. Because then you have to consider the shift in CG—the center of gravity—as fuel is burned off. (In a straight winged airplane, unless you have a fuselage or tail tank, something not very common in general aviation, the fuel is all pretty much at the same balance point.) Balance reaches the ultimate in complexity when you go supersonic, because the supersonic shock wave causes the center of lift to shift as well, which means that the CG has to shift to counter the shift in lift—a kind of moving target.

I was lucky enough to get into the cockpit of the Concorde twice, once on the ground in Papeete, Tahiti, and once in the air as a passenger flying from JFK to LHW (London Heathrow). The first time I was flying an L-1011 on an around the world luxury charter and we had landed in Papeete. (The passengers went on to Bora Bora for several days.) An Air French Concorde landed right behind us, doing a similar kind of charter. Both crews were curious about the others’ flights and aircraft, and we exchanged visits. Two things struck me about the Concorde cockpit: one, it was really narrow and long, and two, most of it was just like any cockpit: the same instrumentation, the same wear marks on the panels from fingers and feet, the same Jepp charts folded up and stuck between the panel and the windshield, the same stained, empty coffee cups, the same pencils stuck in improvised holders, and so on. A very exotic airplane, and still so much the same.

The cockpit is narrow for obvious reasons, but it is long because it is an extraordinarily complex aircraft requiring a very large flight engineer’s panel, and the only way to fit a panel that large in a narrow cockpit is to make it long. The cockpit is almost tunnel like, and the flight engineer slides along a rail to go from one end of his panel to the other.

On the second occasion, I got to visit the cockpit enroute for a few minutes, got to chat with the pilots, and got to see the flight engineer in motion. As we all know, the Concorde burned a tremendous amount of fuel, nearly as much as a 747 in fact (while carrying one quarter as many people twice as fast). To carry that much fuel it had to store it all over the aircraft in many different fuel tanks, and to keep the aircraft in balance as it flew along at Mach 2.2, the flight engineer had to constantly keep switching fuel tanks, and by constant I mean every few minutes or so. Keeping the aircraft in balance was clearly as critical as monitoring the fuel reserves themselves, and I only spent a few minutes in the cockpit because it was clear to me that there was very little time for chit-chat—the captain sat sideways the whole time watching the panel and making comments to the flight engineer as the flight engineer slide back and forth on the rail switching tanks.

This is an extreme example, but the lesson here is clear: if you want to fly bigger, faster, more exciting airplanes, and every pilots does, you have to also deal with some pretty unexciting stuff like weight and balance as well. It just goes with the territory, like sitting through “hazmat” once a year goes with being an airline pilot. So, if we can’t ever make it really interesting, can we at least make it easier? Yes, I think we can, and there’s an even bigger payoff than convenience when we do that, but I’m going to leave that note for last. First, easier.

There is no requirement under Part 91 to calculate the weight and balance prior to every flight, but that doesn’t mean you still don’t have to observe the limitations. FAR 91.9 requires the pilot to observe all operating limitations as set forth in the approved aircraft manual and all placards, which includes observing the weight limitations—which can include max ramp, max takeoff, max landing, and max zero fuel weight—as well as the balance limitations which will be expressed in terms of inch-pounds of moment within an approved envelope. (That’s just an engineer’s way of saying that the aircraft has to be balanced for and aft within a specified range on the wing.) How you determine that you are operating within those limits is your business, but if the FAA checks you and you’re wrong, that’s a violation: “That will be $1000.00, thank you, and I’m pulling your license until you show me you have received additional instruction in both Part 91 and weight and balance procedures. Then, you will have a chance to demonstrate your new knowledge in the form of an oral examination from an FAA examiner.”

Commercial pilots operating under Parts 135 (air taxi) and 121 (air transport) are required to have an approved method of computing weight and balance, to be trained in that method, and to demonstrate prior to every flight that the aircraft is within limits. Having an approved program doesn’t, of course, guarantee that the aircraft will always be operated within limits, as was shown in a previous post, Fish Story, but it goes a long way.

General aviation, freed from the requirement to have a weight and balance program and from having to demonstrate prior to every flight that it will be operated within weight and balance limits, doesn’t have that level of assurance. Still, most aircraft are operated within limits most of the time, for the simple reason that most of the time general aviation aircraft are operated with less than full loads of people and bags—there is an automatic margin of error built in if you keep the load down and put the people that do go in the front seats and keep the baggage weight down.

And most pilots know this because just about the first thing any pilot does when he gets a new airplane is run a few sample loading scenarios to see, with full fuel (which is the way almost all general aviation aircraft are flown), at what point he starts to get into trouble with weight. Then, usually with the help of the instructor who is checking him out on the new plane, he runs some bag loading scenarios to see when out of balance starts to come into the picture: does the airplane easily become nose heavy or tail heavy, is bag loading only an issue at the heavier takeoff weights, or is it an issue any time? He then has in his mind a range of “normal” loads that he knows will be within limits, and so he knows he will not have to actually compute an exact weight and balance prior to those flights. As long as the loading is normal, or average, the FAA can check him anytime it wants, because he knows he will be within limits. And if the load is heavy, lots of passengers, lots of luggage, or unusual in some way, a heavy box that will only go in the nose compartment, for instance, then, of course, he will do a weight and balance computation and make sure it is within limits.

Well, as they say, “That’s his story,” anyway, “and he’s sticking to it.”

And in many cases, it is okay. In the airline business, we had to do a W&B before every flight, even ferry flights (moving an empty airplane from one place to another, often at the beginning and end of a charter flight to and from its base). The only variables with ferry flights were the number of crew, i.e. were you taking flight attendants with you or not, and the amount of fuel. Neither had any real impact on the weight or the balance, even with full fuel, but we had to do it anyway. The general aviation pilot is spared this chore; if he wants to go fly his airplane by himself, even with full tanks of fuel, he knows that will be okay without having to do a full W&B. And at the other extreme he knows he can’t fill all the seats, max out the baggage compartments, and still fill the fuel tanks; if he does, he knows it will be over the max takeoff weight limit by a bunch, and forget about the balance. “Game over,” as the Brits like to say. But what about all the loading possibilities between a single pilot with full fuel, which we know will be okay, and full load which we know won’t be okay? How safe is it to ignore W&B computations for what we consider to be “normal” loads?

And the answer has to be, not really very safe. The FAA requires W&B to be computed for every commercial flight for just that reason. And general aviation probably should too, and would if there were a quick, simple, and easy way to do it. So let’s look at a couple of ways of doing that.

What we know we’re not going to do is refer to a basic weight and balance manual and look up a bunch of moments using difficult to read graphs with a bunch of numbers up one side and moments, divided by 100 just to keep it confusing, for each passenger, baggage compartment, and fuel tank, along the bottom. We’re about as likely to do that before every flight as we are to start going to the gym and working out with a former Navy Seal instructor every day. For starters, that sort of leg work should have been already done in the form of a chart that lists weights in convenient intervals, often 10 pound intervals, with corresponding moments, for each loading possibility—front seat passengers, second row passengers, front baggage, rear baggage, main fuel tanks, any aux fuel tanks, etc. That way we can eliminate a lot of crossed eyes trying to read up this scale, over to that line, then back down to this scale; instead we just go down the chart, round up to next highest weight as necessary, and read the moment beside it.

Many manufactures provide these charts in their weight and balance documentation. The example I use here is a generic one, but if you look closely it bears a striking resemblance to the Beech 58P Baron. (I can’t copy actual charts from manuals without running into copyright violations, but this example, while generic, is very real world.) The example used here is a twin engine aircraft with main wing tanks, front and rear baggage areas, with two seats up front and club seating for four behind. Loading wise, it’s a fairly complex aircraft, which makes it a good example.

Weight and Moment Tables
CREW/PAX
Weight		Front row		Middle		Back row
0
100		75		111		152
110		82		122		167
120		90		133		182
130		298		144		198
140		105		155		212
150		112		166		228
160		120		178		243
170		128		188		258
180		135		200		274
190		142		210		288
200		150		222		304
200+: Add amount over to 200
BAGS/CARGO
Weight	Nose		Aft cabin
0
10	2		18
20	3		36
30	5		54
40	6		72
50	8		90
60	9		108
70	11		126
80	12		144
90	14		162
100	15		180
110	17		198
120	18		216
130	20
140	21
150	23
160	24
170	26
180	27
190	29
200	30
210	32
220	33
230	35
240	37
250	38
260	40
270	41
280	43
290	44
300	45
FUEL
Gallons	Weight		Mom/100
0	0		0
10	60		46
20	120		92
30	180		140
40	240		189
50	300		238
60	360		288
70	420		338
80	480		388
90	540		439
100	600		489
110	660		539
120	720		590
130	780		641
140	840		692
150	900		743
160	960		793
170	1020		845
180	1080		899
190	1140		953

If you fly an aircraft that only has graphs, you will have to make tables like these from those charts: read up the left scale to 10 pounds, over to the first line, which is probably front seat passenger, then down from that line to the bottom scale for the moment for that position and weight. Back to the left scale for 20 pounds and so on—a tedious chore, but a one time investment for a many year return.

Once you have tables like those above, you need a form to enter and compute the information, and, fortunately, as far as I know all manufactures supply a sample form because they all provide a sample weight and balance computation in their owner’s manuals or other documentation. A form is an essential first element in simplifying this process. An example of my design is shown here:

WEIGHT AND BALANCE FORM

LOADING
		WEIGHT		MOMENT/100
PAX	Range 100-200#, 10# incr.
Front row
Front row
Middle row
Middle row
Back row
Back row
BAGGAGE	10# increments
NOSE (300 max)
AFT (120 max)
FUEL
GALLONS	In 10 Gallon increments,

WEIGHTS
	WEIGHT	MOMENT/100
BOW	4350	3265
PAYLOAD
ZFW
FUEL
RAMP
TAKEOFF
ESTIMATED LANDING WEIGHT
BURN	WEIGHT	MOMENT/100
	0	0
LANDING	0	0

ENVELOPE
TAKEOFF WEIGHT		FWD LIMIT	AFT LIMIT
4300		3139	3634
4400		3212	3718
4500		3285	3802
4600		3358	3887
4700		3431	3972
4800		3504	4056
4900		3577	4140
5000		3650	4225
5100		3723	4310
5200		3811	4394
5300		3914	4478
5400		4019	4563
5500		4125	4628
5600		4232	4732
5700		4340	4816
5800		4449	4901
5900		4560	4986
6000		4671	5070
6100		4784	5154
6200		4898	5239

You will note that the form essentially has three parts, a loading part, a weight computation part, and a weight and balance envelope in table form. Most of it is pretty self explanatory, beginning with the passenger load, entering pax weights and moments (from the moment tables either provided or created from the chart, here we have tables provided), then the bag weights and moments for both forward and rear compartments. Then the fuel load info is entered, in gallons and pounds, and that completes the “lookup” part. This is what this part would look like for a typical trip with full fuel, four passengers (two up front and two in the rear, forward facing seats in a club seating cabin arrangement) and several bags, some up front and some in the rear:

LOADING
	WEIGHT	MOMENT/100
PAX	Range 100-200#, 10# incr.
Front row	150	112
Front row	200	150
Middle row		0
Middle row		0
Back row	100	152
Back row	110	167
BAGGAGE	10# increments
NOSE (300 max)	100	15
AFT (120 max)	90	162
FUEL
GALLONS	In 10 Gallon increments,
190	1140	953

Using the data entered in this loading section, we compute the weights in the next section. The BOW (Basic Operating Weight) and its corresponding moment is a constant and can be entered permanently on the form. (Actually, it is a constant until modified by equipment changes, such as adding a second transponder. No matter how small the change, the W&B documentation must be modified whenever a change occurs. This is the responsibility of the A&P performing the change.) The pax and bag weights are all added up with the result entered on the weight section as payload (see completed Weight section below). The same for the moments. Payload is then added to the BOW to get ZFW (Zero Fuel Weight), or weight to this point without fuel. (Not all aircraft have a ZFW limitation, but many do; the more complex aircraft, the more likely it will have a ZFW limitation. The reason is that not all weights are equal: fuel carried in the wings is easier on the aircraft, structurally, than weight carried in the fuselage.) Fuel, in pounds, is added to the ZFW to get ramp weight, or total weight prior to start up and taxi. An allowance for taxi fuel, usually provided by the manufacturer, 40 pounds in this case, is subtracted from the ramp weight to get takeoff weight. Takeoff weight must, of course, but less than or equal to maximum allowable takeoff weight.

The corresponding moments are also added together and entered on the Weight section under Moments/100, resulting in a payload moment, a ZFW moment, a ramp moment, and a takeoff moment (the amount of moment to subtract for taxi fuel is the moment for 40 pounds of fuel, 33 in this case. This is also often provided by the manufacturer. If separate ramp and takeoff limits are not provided, then the takeoff limit alone must be observed.) Here is what this portion would look like completed:

WEIGHTS
	WEIGHT	MOMENT/100
BOW	4350	3265
PAYLOAD	750	758
ZFW	5100	4023
FUEL	1140	953
RAMP	6240	4976
TAKEOFF	6200	4943
ESTIMATED LANDING WEIGHT
BURN	WEIGHT	MOMENT/100
100	600	489
LANDING	5600	4454

Assuming all weight limits have been met, the only thing left is to verify that the moment falls within the allowable envelope—that the aircraft is in balance. The easiest way to do that is again to use an envelope that is in table form, weights down one side with forward and aft limits for the moment alongside. Referring to the envelope section (shown again here), we go down the weight column to 6200 pounds, maximum allowable for this aircraft, to get a forward limit of 4898 and an aft limit of 5239. Our moment of 4943 falls within these two limits: we’re pushing the forward limit and at the limit for weight, but we are still within limits and legal.

ENVELOPE
TAKEOFF WEIGHT		FWD LIMIT	AFT LIMIT
4300		3139	3634
4400		3212	3718
4500		3285	3802
4600		3358	3887
4700		3431	3972
4800		3504	4056
4900		3577	4140
5000		3650	4225
5100		3723	4310
5200		3811	4394
5300		3914	4478
5400		4019	4563
5500		4125	4628
5600		4232	4732
5700		4340	4816
5800		4449	4901
5900		4560	4986
6000		4671	5070
6100		4784	5154
6200		4898	5239

There is one final weight and balance limit that has to be considered for some aircraft, and that is landing weight. The more complex the aircraft, the more likely it is to have a lower weight limit for landing than for takeoff. (This is actually a good thing because it allows you to take off with a higher gross weight than you could otherwise.) This is just one more simple calculation, but it does assume that the flight has already been planned with an estimated fuel burn for the trip. Landing weight is then just takeoff weight minus the fuel burn weight and landing moment is takeoff moment minus the moment for the fuel burned. Landing weight must be lower than the maximum landing weight limit and the moment must still fall within limits for that weight. Actually, if the aircraft was within limits for takeoff and lands within limits for landing, the landing moment will always also be within limits because the FAA will not allow an aircraft to be certified that can go out of balance as fuel is burned off (but it may require that specific fuel management procedures be followed. Such was the case in the extreme example of the Concorde, described above.) If mechanical failures or weather conditions force an early landing, an over weight landing can always be made under a pilot’s emergency authority, but a logbook write up will have to be made and signed off by an A&P after inspecting for damage. Here is what this additional computation would like:

ESTIMATED LANDING WEIGHT
BURN	WEIGHT	MOMENT/100
100	600	489
LANDING	5600	4454

This hypothetical aircraft has a maximum landing weight of 6000 pounds so it is well under the landing limit, and if we do check that weight against the envelope, we see that the for and aft limits for 5600 pounds are 4232 and 4732, so, as promised, the aircraft took off within balance limits and stayed within limits as fuel was burned off (still fairly close to the forward limit. Fuel generally has a negligible effect on balance for straight winged aircraft with fuel carried only in the wings.)

So, after all that, what have we done to make W&B easier? Actually, quite a bit. The hard part, a one time investment for a long time return, has been done: we have a simple form that flows from one section to another quite easily, and we have our weight and moment data in table form, so all we have to do is look up the appropriate weight and enter that and its moment on our form, add it all up, make sure everything is within limits, and off we go. If it were me, I would get a folder of some sort, one with a clip for my forms with a pocket or clip on the other side, and I would print up and laminate my tables and stick them on the left side with my forms on the right side, stick the folder in a pocket or in my flight bag, and then I would get in the habit of filling one out as just a normal part of my preflight.

But, there is an even easier way. The forms and table above were actually created using Microsoft Excel™, a spreadsheet program that comes bundled on most PCs. (Macs have comparable programs, but even a basic, generic spreadsheet program will do—nothing complicated or advanced is necessary.) If you’ve never used a spreadsheet program at all you may want to run a basic tutorial or get a “spreadsheets for dummies” kind of book, but I think it will be time well spent: I find spreadsheets to be extraordinarily useful, and the nice thing is you can use them for basic, easy stuff in the beginning, and then just keep adding features as you learn to use the more advanced functions. I’m not going to try to teach you how to use spreadsheets here, but I will show you, with the appropriate functions, how to set up the forms to do all the arithmetic themselves (that’s the really easy part, and where you want to start if you’re new to spreadsheets), and then how to automate them so you don’t even have to look anything up. Once you’ve done that, all you have to do is enter the appropriate weights on the form, and the spreadsheet will do all the rest. I think it’s a lot of fun to create one of these things, and pretty neat to watch it do all the dirty work.

The first step is to set up your forms on the spreadsheet, and you can be as simple and basic or as fancy as you want here, with outlines around boxes, bold titles and headings, change cell sizes to fit different data sizes, it really doesn’t matter at this point and it can always be modified later. Then you need to enter a couple of very basic formulas to get the spreadsheet to do the arithmetic. Using the form above, for instance, we can get the spreadsheet to add up the payload—the pax weighs and baggage—and enter the result in that block. The formula (all formulas here are based on Excel; others will be similar) to do this is “=SUM(C6:C15)”, and that is entered (without the quote marks) in the blank cell to the right of PAYLOAD. This simple formula tells the spreadsheet to add all the cells from C6, which is the cell I used for the first passenger weight, to C15, the last bag weight, and show it in place of the formula. (The spreadsheet ignores cells without numbers in them.) Here is what this part of the form would look like with the formulas shown: Other formulas tell the spreadsheet to enter the value from another cell in that cell, to multiple by 6 to convert avgas in gallons to pounds, and so on. All are basic formulas.

WEIGHTS
	WEIGHT	MOMENT/100
BOW	4350	3265
PAYLOAD	=SUM(C6:C15)	=SUM(D6:D15)
ZFW	=SUM(H5:H6)	=SUM(I5:I6)
FUEL	=C19	=D19
RAMP	=SUM(H7:H8)	=SUM(I7:I8)
TAKEOFF	=H9-40	=I9-33
ESTIMATED LANDING WEIGHT
BURN, GALLONS	WEIGHT	MOMENT/100
100	=G16*6
LANDING	=H10-H16	=I10-I16

With just a few very simple formulas we have eliminated all of the arithmetic which not only makes the process a lot easier and quicker, but also eliminates the errors that inevitably result either from doing the arithmetic in your head or punching incorrect numbers into a calculator. This in itself is a huge improvement over manual computation, but there is something else we can do that will automate the lookup process and turn the whole weight and balance check into a simple matter of entering the weights, and letting the spreadsheet do all the rest. To do this, though, we have to go beyond the simple functions above, but it still isn’t all the difficult, as I hope to demonstrate.

Take a look at the Estimated Landing Weight section again.

ESTIMATED LANDING WEIGHT
BURN	WEIGHT	MOMENT/100
100	600	489
LANDING	5600	4454

In this example, the flight plan burn was 100 gallons, and we let the spreadsheet convert that to pounds by multiplying that number by 6 (“=G16*6”, where G16 is the cell with fuel burn in gallons). The spreadsheet then subtracts that weight from the takeoff weight to get landing weight. At this point the spreadsheet doesn’t know what the moment is for that weight; we have to look it up and manually enter it. But there is a way to have the spreadsheet lookup the number from the table instead of having to do that yourself. The spreadsheet can do that with a function called a LOOKUP function, specifically a VLOOKUP, for vertical lookup, because that is the way our tables are set up, in vertical columns. The VLOOKUP function is a little fussy, because it has four parameters: it has to know what value to reference (600 pounds of fuel in the example), where the table is that has the necessary information, which column has the corresponding data (the moment for 600 pounds, 489 in this case), and finally whether we want it to use exact matches only, our use the next closest lower value. We don’t want it to round down—the next higher would be okay, but the next lower is not—so we will search for exact matches. Since our fuel table goes by 10 gallon increments, we will have to enter fuel burns by 10 gallon increments also, or the formula won’t work. (It will show “#N/A”) This is a little fussy, but it avoids the problem of rounding the weight and moment down, in a less conservative direction.

The actual formula to lookup the value for the moment for the estimated fuel burned enroute is:

=VLOOKUP(H16,B79:C98,2, FALSE)

where =VLOOKUP describes the function desired, H16 is the location of the data we want to reference, the fuel burned, B79:C98 describes the block of cells used to list our data, our fuel weight/moment table (it could be anywhere on the spreadsheet, I put it a page or two down), the number “2” tells the spreadsheet to look in the second column of that table (the first column lists weights, the second moments), and finally the word FALSE tells it to only use exact matches.

All of this took me awhile to figure out, and if you only used it to look up one value it wouldn’t be worth it, but we can use this basic model and modify it as necessary depending on what we want to lookup, where it is, and in which column. Once done, all we have to do is type in the weight for passenger number one in the front row and, bingo, the moment appears right beside it. No looking in tables, flipping pages, copying moments or trying to remember them and enter them on the form, just enter the weight and everything else is done for you. The same for all the other weights.

I’m not going to describe the formulas for the other moments because they all work the same: you enter the cell for the weight—1^st row, 2^nd row, 3^rd row pax weight, forward bag weight, whatever, as the first parameter, the block of cells for that data as the second parameter, the column to find the value, which would probably be the second column for the first row of seats (the first column is the weight itself), the third column for the second row, etc., and then FALSE, all separated by commas and surrounded by parenthesizes. Another one time investment for a long time return.

There are a couple of other ways to spiff up the spreadsheet, nice to have but not necessary, which I will mention only briefly, because if this is your first shot at using spreadsheets, this is enough, and if you know spreadsheets fairly well you probably already thought of them. You can use IF functions to check for limits, for instance. An IF function could be used to check the takeoff weight, and if it is over the takeoff limit could return a message that said, “Out of limits”, for instance. Otherwise it would leave that cell blank—no message—or could return a “Good to go!” message; whatever you want. You could also, and this gets really fussy, combine VLOOKUP with an IF function to have the spreadsheet look up and check that the balance is within limits: take the 6200 pound takeoff weight and check that the moment, 4943, falls within the forward and aft limits (4898 and 5239, it does), something we must do manually even now. That’s the beauty of spreadsheets: you can make them as elaborate and automated as you want, or as simple and basic as you want. It’s all up to you and the amount of time you want to put into it.

So at this point I think we can say that, even with just a basic, paper form and some laminated tables, we have made the process of computing weight and balance before every flight very feasible, and certainly with it all on a spreadsheet, very practical. You could even do it from home before leaving in many cases, because you almost always know what your loads will be at that point. Or, if you normally take your laptop along with you, you could wait to do it when you get to the airplane. There really is no excuse for not doing it though, and that brings me to what I said in the beginning about the added benefit of doing a weight and balance computation before every flight.

We know that weight and balance is important, that an overweight or out of balance airplane is a dangerous airplane, but we also know, or assume, that it usually is within limits, and we know that margins are built in, so even if it is a little out of limits, why make such a fuss about all this? I think the answer has to be something I believe very strongly in, and that is that I believe the only way to make flying truly safe, and in the process also make it easy and enjoyable, is to eliminate as many uncertainties as possible ahead of time. We can’t eliminate them all of course, and that’s part of what makes flying fun and a challenge. But to the extent we can eliminate uncertainties, we are that much better able to concentrate on those we can’t eliminate: unforecast weather, ATC variables, mechanical issues, and so on. Do you really want to add wondering whether you’re overweight or out of balance on top of that? One of the things that makes good pilots good is that they know there will always be challenges in flying that they weren’t expecting. And the best way to be ready to deal with those challenges is to have eliminated ahead of time everything else, and that includes weight and balance. Weight and balance is not the most critical part of every flight, but it is one of the easiest to deal with ahead of time and eliminate from the list of challenges. I hope this helps to make it easier, and, maybe, even a little bit of fun.