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Weight and Balance Handbook

FAA-H-8083-1B Version 2016
All Library Documents FAA Source

Chapter 9

Weight and Balance Control—Commuter Category and Large Aircraft

  • Basic operating weight — 105,500 lb
  • Basic operating index (total moment/1,000) — 98,837.0
  • MAC — 180.9 in
  • LEMAC — 860.5
Figure 9-4. Loading schedule.
Figure 9-4. Loading schedule.

Figure 9-5 illustrates passenger, cargo, and fuel loading tables. Using these tables, determine the moment indexes for the passengers (PAX), cargo, and fuel.

The airplane is loaded in this way—passengers (nominal weight 170 pounds each):

  • Forward compartment — 18
  • Aft compartment — 95

Cargo:

  • Forward hold — 1,500 lb
  • Aft hold — 2,500 lb

Fuel:

  • Tanks 1 and 3 — 10,500 lb each
  • Tank 2 — 28,000 lb
Figure 9-5. Loading schedule for determining weight and CG.
Figure 9-5. Loading schedule for determining weight and CG.

The formula in Figure 9-6 can be used to determine the location of the CG in inches aft of the datum.

Figure 9-6. Determining the location of the CG in inches aft of the datum.
Figure 9-6. Determining the location of the CG in inches aft of the datum.

Determine the distance from the CG to the LEMAC by subtracting the distance between the datum and LEMAC from the distance between the datum and the CG. [Figure 9-7]

Figure 9-7. Determining the distance from the CG to the LEMAC.
Figure 9-7. Determining the distance from the CG to the LEMAC.

The location of the CG in percent MAC must be known in order to set the stabilizer trim takeoff. [Figure 9-8]

Figure 9-8. Determining the location of the CG in percent MAC.
Figure 9-8. Determining the location of the CG in percent MAC.

Operational Empty Weight (OEW)

Operational empty weight (OEW) is the basic empty weight or fleet empty weight plus operational items. The operator has two choices for maintaining OEW. The loading schedule may be utilized to compute the operational weight and balance of an individual aircraft, or the operator may choose to establish fleet empty weights for a fleet or group of aircraft.

Reestablishing the OEW

The OEW and CG position of each aircraft should be reestablished at the reweighing. In addition, it should be reestablished through calculation whenever the cumulative change to the weight and balance log is more than plus or minus one-half of 1 percent (0.5 percent) of the maximum landing weight, or whenever the cumulative change in the CG position exceeds one-half of 1 percent (0.5 percent) of the MAC. In the case of rotorcraft and aircraft that do not have a MAC-based CG envelope (e.g., canard equipped airplane), whenever the cumulative change in the CG position exceeds one-half of 1 percent (0.5 percent) of the total CG range, the weight and balance should be reestablished.