Weight and Balance Calculations For the GA Plane

As the pilot, you are in charge of a safe loading and no overload for your airplane. Before a flight, the pilot will have to compute that the total weight installed into the plane in terms of fuel, passengers and baggages does not exceed the useful load of it. The disposal of weight is also a factor as it affects the plane's center of gravity which has to remain within the permissible envelope to ensure stability and maneuvrability. The weight and balance of a airplane will affect the takeoff distance, the rate and angle of climb, the maximum ceiling or range, the landing speed and roll or, at last, how the plane is affected by maneuvers' or turbulence stress. In the real life, all values useful to such calculations is providing by planes' manufacturers under the form of the 'Airplane Flight Manual,' which provides general data for your plane's model and the 'Aircraft Weight and Balance Report,' for your particular aircraft which is specifically weighed and a report established function of how it is equipped with, before sale. for this tutorial, we'll use anglo-saxon units only (check 'Les calculs de poids pour un avion de tourisme' for the numbers in the metric system)

Most Usual Weight and Balance Values

Weight and balance values of use with the FS franchise are the following as they mostly are the same than that used in the real world:

• Basic Weight Empty, or Basic Empty Weight. The weight of the airplane with all optional equipment included, and usually also full oil
• Useful load. The difference between max gross take-off weight and basic weight empty. Useful load usually concernes fuel, crew, passengers, baggage, etc. or all what can be embarked onboard
• Max Gross Takeoff Weight. The maximum takeoff weight approved for starting the takeoff run, which is the basic empty weight plus useful load
• Maximum Landing Weight. Some GA advanced planes may be deviced by designers for landing taking in account a important consumption of fuel during a flight and appreciably lesser weight at landing as such a concept allows for saving structural weight. In case of short duration flight, fuel will have to be jettisoned to reach the value

GA Standard Passengers, Fuel Values

As far a GA planes are concerned, no weighing instruments are used to estimate passengers' weight. Standard values are like, which accomodate for summer/winter clothing and allowance of 8 lbs of carry-on luggage: males: 182-188 lbs, females: 135-141 lbs, children (under 12): 75 lbs, infants (under 2): 30 lbs. In terms of fuel weight, the following are of use: to convert liters to U.S. gallons, multiply by .264178; to convert liters to Imperial gallons (older Canadian planes, for example), multiply by.219975. Aviation gasoline weighs 1.58 lb/liter, 6. lb/U.S. Gallon, and 7.20 lb/Imp. gallon. Aviation oil weighs 1.95 lb/liter, 7.5 lb/U.S. Gallon, and 8.5 lb/Imp. gallon

The Concept of Center of Gravity

For any plane, a manufacturer establishes forward and aft limits for the center of gravity (C.G.)'s position. That is to insure the plane's maneuvrability remains in a given envelope. The C.G. is affected by the load embarked generally. For a plane the use of fuel during a flight is important, that lesser weight necessitates the pilot computes the weight and balance also for the end of the flight. In FSX the placement of the C.G. is displayed automatically within the Fuel and Useful Load menu. In the real life a pilot will most often use -- and also for weight calculation -- in terms of a GA plane, tables and graphs included with the Airplane Flight Manual. Applications for smartphones or PC freewares are also now available. Lateral C.G. is not computed for GA planes as a pilot must be aware however of adverse conditions of a laterally unbalanced plane. In terms of flight behavior, the C.G. impacts like: with a C.G. near the aft limit -- or a tail-heavy condition -- a plane is less stable and stalling at a slightly lower airspeed; with a C.G. near the forward limit -- or a nose-heavy condition -- a plane is more stable, stalling at a higher speed as more pressure, generally, is needed on the elevator controls to raise the nose

More details can be found about the weight and balance concepts for the general aviation on dedicated pages or sites, like, for example, that English-speaking website

Function of the versions of the Flight Simulator franchise, both the empty weight and max gross takeoff weight are to be found at the [WEIGHT_AND_BALANCE] section in the aircraft.cfg file. Thus the values may be adjusted to real life ones, from which they are sometimes departing. FSX especially allows to a fine tuning of the load characteristics for a GA plane, concerning the load of passengers, lugage, and fuel. Some tweaking further allows to refine that tuning. Check that with our 'Tweaking Payload Stations for FSX Original, or Imported Heavies' tutorial. Albeit dedicated to airliners, it can be adapted to GA planes. JUST THINK TO ABIDE BY the safety procedures concerning the handling of the FSX folders and files, of which making backup files to be able to be back to original files in case of trouble!