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weight is 14,729 pounds, the total moment index is
43,139 lb-in/100. The CG is located at fuselage station
292.9.
5. Check to determine that the CG is within limits for
this weight. Refer to the Weight and Balance Diagram
in Figure 7-12 on Page 7-14. Draw a horizontal line
across the envelope at 14,729 pounds of weight and a
vertical line from the CG of 292.9 inches aft of datum.
These lines cross inside the envelope verifying the CG
is within limits for this weight.
Determining the Changes in CG When Passengers are
Shifted
Consider the airplane above for which the loaded weight
and CG have just been determined, and determine the
change in CG when the passengers in rows 1 and 2 are
moved to rows 8 and 9. Figure 7-13 shows the changes
from the conditions shown in Figure 7-7. There is no
weight change, but the moment index has been increased
by 1,155 pound-inches/100 to 44,294. The new CG is at
fuselage station 300.7.
This type of problem is usually solved by using the
following two formulas. The total amount of weight
shifted is 550 pounds(300 + 250) and both rows of
passengers have moved aft by 210 inches (410 - 200 and
440 - 230).
The CG has been shifted aft 7.8 inches and the new CG is
at station 300.7.
7–16
Figure 7-14. Loading data for cargo configuration.
Figure 7-15. Flight manifest of a Beech 1900 in the cargo
configuration.
Determining Changes in Weight and CG When the
Airplane is Operated in its Cargo Configuration
Consider the airplane configuration shown in Figure 7-14.
The airplane is loaded as recorded in the table in Figure 7-
15. The basic operating weight (BOW) includes the pilots
and their baggage so there is no separate item for them.
The arm of each cargo section is the centroid of that
section, as shown in Figure 7-14.
The fuel, at the standard temperature of 15ºC weighs 6.8
pounds per gallon. Refer to the Weights and Moments -
Usable Fuel in Figure 7-11 on Page 7-14 to determine the
weight and moment index of 370 gallons of Jet A fuel.
The CG under these loading conditions is located at station
296.2.
Determining the CG Shift When Cargo is Moved From
One Section to Another
When cargo is shifted from one section to another, use this
formula:
If the cargo is moved forward, the CG is subtracted from
the original CG. If it is shifted aft, add the CG to the
original.
7–17
Determining the CG Shift When Cargo is Added or
Removed
When cargo is added or removed, add or subtract the
weight and moment index of the affected cargo to the
original loading chart. Determine the new CG by dividing
the new moment index by the new total weight, and
multiply this by the reduction factor.
Determining Which Limits Are Exceeded
When preparing an aircraft for flight, you must consider all
parameters and check to determine that no limit has been
exceeded.
Consider the parameters below, and determine which limit,
if any, has been exceeded.
• The airplane in this example has a basic empty weight
of 9,005 pounds and a moment index of 25,934 poundinches/
100.
• The crew weight is 340 pounds, and its moment/100 is
439.
• The passengers and baggage have a weight of 3,950
pounds and a moment/100 of 13,221.
• The fuel is computed at 6.8 lbs/gal:
The ramp load is 340 gallons, or 2,312 pounds.
Fuel used for start and taxi is 20 gallons, or 136
pounds.
Fuel remaining at landing is 100 gallons, or 680
pounds.
• Maximum takeoff weight is 16,600 pounds.
• Maximum zero fuel weight is 14,000 pounds.
• Maximum landing weight is 16,000 pounds.
Take these steps to determine which limit, if any, is
exceeded:
1. Determine the zero fuel weight, which is the weight of
the aircraft with all of the useful load except the fuel
onboard.
The zero fuel weight of 13,295 pounds is less than
the maximum of 14,000 pounds, so this parameter is
acceptable.
2. Determine the takeoff weight and CG. The takeoff
weight is the zero fuel weight plus the ramp load of
fuel, less the fuel used for start and taxi. The takeoff
CG is the (moment/100 ÷ weight) x 100.
The takeoff weight of 15,471 pounds is below the
maximum takeoff weight of 16,600 pounds, and a
check of Figure 7-12 on Page 7-14 shows that the CG
at station 298.0 is also within limits.
3. Determine the landing weight and CG. This is the zero
fuel weight plus the weight of fuel at landing.
The landing weight of 13,975 pounds is less than the
maximum landing weight, of 14,000 to 16,000 pounds.
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Aircraft Weight and Balance Handbook(29)
