The current limit of the position in pounds or kilograms is displayed to the right of each position input field. An optional 2^nd column selectable by radio button is:

• no display — no second field is displayed. This is the default.
• balance arm inches &mdash: the balance arm in inches used to calculate the position moment, regardless of whether the weight unit is pounds or kilograms.
• linear loading per inch — the current linear limit per inch. If the weight unit is pounds, it is pounds/inch; if kilograms, it is kilograms/inch. Kilograms/inch is an obvious mixing of systems, but that's what Boeing does in the documentation.

The selection applies only to the current page and current position configuration. New aircraft pages and changing the position configuration will use the no display default.

The aft body cumulative loading plots use the same segments as the Main Deck + Lower Deck Combined Linear Loading, except that if a segment straddles b.a. 1240, only the part aft of b.a. 1240 is included. The x-axis is the b.a., and there's a vertical line for the forward end of each segment. The y-axis is the cumulative weight. The yellow lower limit line is the normal aft body cumulative limit. The upper red line is the increased aft body cumulative limit. If the normal limit is exceeded, the increased limit is used and the forward takeoff c.g. limit is changed to 15.5% mac. The line currently in use has the greater line width.

Not yet written.

Typically you can carry 747-400 ballast fuel in either the main wing tanks or the center tank. If only one choice is shown, that means the operator has chosen to allow only that way for whatever reason.

If a choice is shown, the default used by the operator is shown as selected. If you change the selection and ballast fuel has been entered or is entered, the following occurs:

• If the Wing Tanks are selected, fuel is allocated just as it would be if there were no ballast.
• If the Center Tank is selected, fuel is allocated by first putting the ballast amount in the center tank and then allocating the remainder in the usual way.

In either case, the ballast fuel becomes part of the zero fuel weight but not part of the usable fuel. The 'total fuel' under Fuel Load includes ballast fuel.

Clicking on the ballast fuel label will bring up an alert telling you what the current ballast requirement is.

If only one Basic Operating Wt is shown, the operator has chosen not to use multiple BOWs, and you cannot change the BOW.

If multiple BOWs are shown, you can use the radio buttons to choose the BOW configuration you wish to use.

When you change the BOW, the balance box will recalculate.

• adding or removing FAKs (Fly Away Kit)
• adding or removing bulk spares
• adding or removing passenger seat pallets

You can enter three things into a cargo position in the following order:

1. the pallet weight, and you can optionally append whether the weight is in pounds (P) or kilograms (K) and the pallet height is low (L), medium (M), high (H), or none (N).
2. the pallet ID, up to 12 characters.
3. the pallet destination, up to 4 characters.

The rules of entry are:

• Alpha characters can be either upper or lower case. The program changes all lower case to upper case.
• Separate the 3 items by a space when supplying all 3. If you're supplying a weight and a destination, leave 2 blanks between them to indicate the absence of a pallet ID. If you're supplying a weight and a pallet ID, you don't need a space after the ID, and if you're just entering a weight, no trailing spaces are needed.
• The P or K (pounds or kilograms) and pallet height L, M, H, N (low, medium, high, none) that can optionally be appended to the weight must NOT be separated from the weight or each other by a space. The order of the appended codes is unimportant.
• If the pallet height is not supplied, the program assigns a default height of H for the main deck and L for the lower deck.
• If a P or K is not appended a default weight unit is applied as follows:
• If it's the first weight to be entered, the default is whatever the airplane's weight unit certification is.
• If it's not the first weight, the default is whatever was used for the previously entered weight.

Some examples:

Draging and Dropping:

You can drag and drop any position's pallet into any other position or to Pallet Parking so long as the drag and drop doesn't cause a limitations violation. Each position name serves as a 'handle'. To drag a pallet from one position to another, click and hold on the position name and drag it over another position name and release. The contents of the two positions will be swapped if possible. If the swap can't be done, you'll get a message saying why.

Blocked Positions:

If a position overlaps other positions, entering weight into that position causes a 'blocked' message to appear on the other positions.

Not yet written.

Not yet written.

JWB allocates fuel as follows:

1. Main Tanks 1, 2, 3 and 4 equally until Main Tanks 1 and 4 are full.
2. Main Tanks 2 and 3 equally until Main Tanks 2 and 3 equal 6500 gallons (24605 liters) per side.
3. Reserve Tanks 2 and 3 equally until full.
4. Main Tanks 2 and 3 equally until full.
5. Center tank until full.

Boeing says, "Fuel density must be between the minimum allowable fuel density of 6.0 LB/GAL (0.7190 KG/L) and the maximum allowable fuel density of 7.1 LB/GAL. (0.8507 KG/L). Gross weight may be restricted due to fuel density (refer to CHP-SEC 1-05-xxx for additional information)."

JWB checks to see if the fuel density is within the limits for the current takeoff weight and issues an error message if it is not. The max fuel density is always 7.1 LB/GAL (0.8507 KG/L). However, the minimum fuel density changes with takeoff weight, and for the 747-400BCF the takeoff CG is a determing factor as well.

For formatting convenience, the fuel density is shown to four decimal places whether it's in LB/GAL or KG/L. When keying in the fuel density, you need only enter as many decimal places as necessary. For example, if the fuel density is given to you as '7.0', you only need enter a '7'. On entry that will display as '7.0000'.

Clicking on the fuel density label will bring up an alert telling you what the current limits are.

The fwd body cumulative loading plots use the same segments as the Main Deck + Lower Deck Combined Linear Loading, except that if a segment straddles b.a. 1240, only the part forward of b.a. 1240 is included. The x-axis is the b.a., and there's a vertical line for the aft end of each segment. The y-axis is the cumulative weight. Aircraft that have a max zfw of 610000 lbs or less have only one fwd body cumulative limit line in yellow. That line is also used for aircraft that have a max zfw greater than 610000 lbs if the current zfw is 610000 lbs or less. An aircraft having a max zfw of 635000 lbs has a second, more restrictive line in red that defines the max cumulative loading at that weight. If the current zfw is between 610000 and 635000, the fwd cumulative limit to be used is shown by a third line between the other two. That line is an interpolation between the other two for the weight of the current zfw above 610000. For example, if the zfw is 622500 lbs, which is halfway between 610000 and 635000, the middle line will be halfway between the other two. Whichever line is in use as the current limit is shown with a wider line width than the others.

Use the Hazmat Onboard radio buttons to indicate the absence or presence of hazardous materials in the load. The default is NO. Nothing immediately visible happens when you use the buttons, but if you select YES, a HAZMAT ON BOARD message will appear on the W&B report.

Not yet written.

The linear load is the lbs-per-linear-inch along the longitudinal axis of the airplane. The Main Deck + Lower Deck Combined Linear Loading plot shows that loading and the associated limits. The horizontal axis (x-axis) is the b.a., the vertical axis (y-axis) the lbs-per-linear-inch. The plot of the limits is functionally equivalent to that in the Weight and Balance Control and Loading Manual, 1-60-001. JWB adds vertical lines to the plot with each line starting at a linear load of 0 lbs-per-linear-inch and then rising to what the lbs-per-linear-inch load at that b.a. segment is. If the vertical line rises higher than the limit line at that point, the linear load limit has been exceeded.

The vertical line for each segment along the b.a. axis is unique insofar as the positions, both upper and lower deck, that contribute to the linear load across that segment. The linear load of a segment is the sum of the linear load of the positions straddling the segment. You can see the segment definitions by clicking on the (debug) characters at the end of the plot title. Two lists will be displayed. The first list has a line for each occurence as you proceed from forward to aft of each position edge encountered. With that information you can verify that the second list, with a line for the middle of each segment and showing which positions are involved, are correct.

Not yet written.

Pallet Parking (from here on abbreviated as PP) acts like any other position in that you can enter pallet information just as you would in cargo positions in the airplane. You can also drag and drop into or out of PP to the aircraft cargo positions.

• PP weight is not included in the cargo weight. If you drag a pallet from a cargo position to PP, that weight comes out of the cargo weight.
• PP doesn't have a maximum weight. When you drag PP to a cargo position, the weight will be checked against the position's max.
• PP doesn't look at the pallet height. When you drag PP to a cargo position, the pallet height will be checked against the position's height.

There must be at least one Position Cfg for an aircraft. There are usually more than one. When you bring up an unloaded aircraft, you can select which Position Cfg you want using the radio buttons. The default is the first one. If you change the Position Cfg while loading an aircraft, all entries to the old configuration disappear.

If you bring up an aircraft with a previously entered load, the only Position Cfg shown is the one in use when the load was sent to the SERVER or to LOCAL storage. In such a case, you can change the load, but not the Position Cfg.

The weight unit the display is using is shown by which Weight Unit Displayed radio button is selected and by the color of the weights.

Pound weights are in this color (aquamarine), as are moments and fuel density using pounds as the weight unit.

Kilogram weights are in this color (greenyellow), as are moments and fuel density using kilograms as the weight unit.

The weight unit the airplane is certified for is shown by the color of the aircraft tail number and the border surrounding the balance box. When an aircraft's page comes up, the Weight Unit Displayed has that weight unit selected.

You can temporarily change the weight unit displayed by selecting the Kilograms or Pounds radio buttons under Weight Unit Displayed.

Weights in the pallet positions are a special case. When entering them, you can append a P or K to the weight to make it pounds or kilograms respectively. Doing so does not change the Weight Unit Displayed other than for the single position you entered, and pallet positions always retain the weight they were entered in.

Boeing publishes limits in both pounds and kilograms. However, the length unit is always inches, even when using kilograms. Thus moment limitations are in pound-inches (lb-in) or kilogram-inches (kg-in).

Fuel density is in pounds per gallon (lbs/gal) or kilograms per liter (kgs/L).

The conversion factors used are:

Separate conversion factors for lb-in to kg-in and kg-in to lb-in are unnecessary since both use inches as the length. Thus the lbs to kgs and kgs to lbs conversion factors are used for moment conversion.

When using both pounds and kilograms, be aware of Boeing's statement on the subject:

When totals or summations are required the English values are summed separately from the metric values. Differences may occur when comparing the English total with the metric total due to round off. — Weight and Balance Control and Loading Manual, 1-00-001, Page 6 of 6, Jul 29/2003, D043U542-SIA1

Here's what can happen: Suppose you enter a one kilo load in each of five positions of an airplane certified for pounds. Internally each of those five positions would be held as 2.20462262185 lb, but each would be rounded when displayed to 2 lb. When the program adds the internal representation of the weights, their sum would be 5 x 2.20462262185 = 11.02311131092, and that sum would be rounded to the nearest whole pound and displayed as 11. Adding the 5 rounded displayed values gives 10.