Brunei DCA CPL(A) Mass & Balance Exam key terms

The quantity of matter in an aircraft, measured in kilograms or pounds. In mass and balance work it is the starting value from which all weight-related limitations and performance calculations are derived.

The force exerted by gravity on an aircraft's mass, equal to mass multiplied by gravitational acceleration. Load sheets and limitations are usually expressed as mass, but performance data such as take-off distance depends on weight.

The mass of the aircraft with structure, powerplant, systems, unusable fuel, and all operating equipment and fluids included, but excluding crew, passengers, usable fuel, and payload. It is the foundation of every load calculation.

Basic empty mass plus crew, crew baggage, catering, potable water, and other operational items. It excludes usable fuel and traffic load and is the mass from which the load sheet calculation begins.

Dry operating mass plus take-off fuel. It represents the aircraft mass at the start of the take-off run before any payload is added and is used for some performance and fuel-planning checks.

The total mass of passengers, baggage, cargo, and mail carried for revenue. It is added to dry operating mass and fuel to obtain the take-off mass, and it must be distributed so the centre of gravity stays within limits.

The revenue-earning mass an aircraft carries, comprising passengers, baggage, cargo, and mail. Payload is limited by structural mass limits, available space, and the need to keep the centre of gravity within its certified range.

The highest mass at which the aircraft may begin the take-off run, approved by the manufacturer and limited by structure, climb performance, and runway length. It is a certified limit that must never be exceeded.

The highest mass at which the aircraft may touch down, set by structural strength of the landing gear and airframe. A flight may take off heavier than this only if fuel burn en route reduces mass to the limit before landing.

The highest mass of the aircraft with usable fuel excluded, covering structure, crew, and traffic load. It protects the wing and fuselage structure from excessive bending loads when fuel is absent from the tanks.

The highest mass permitted on the apron before engine start, including taxi fuel. It exceeds maximum take-off mass by the fuel expected to be burned during taxiing to the runway holding point.

The lower of the structural maximum take-off mass and the performance-limited take-off mass for the actual runway, weather, and obstacle situation. It is the figure the crew must verify before departure.

The highest mass at which the aircraft can satisfy all applicable take-off, climb, obstacle-clearance, and landing requirements for the specific conditions. It may be lower than the structural limits and is often the controlling value.

The actual mass of the aircraft at any moment excluding usable fuel, obtained by adding dry operating mass and traffic load. It is compared with the maximum zero fuel mass to confirm structural compliance.

The actual mass of the aircraft on the apron before taxi, equal to take-off mass plus taxi fuel. It is checked against maximum ramp mass to ensure the structural limit is respected before engine start.

The actual mass of the aircraft at the start of the take-off run, comprising dry operating mass, traffic load, and take-off fuel. It must not exceed the regulated take-off mass for the conditions.

The actual mass of the aircraft at touchdown, equal to take-off mass minus trip fuel burned. It must not exceed maximum landing mass, and it must satisfy landing distance and go-around performance requirements.

The point through which the total weight of the aircraft acts. Its longitudinal position is expressed as a distance from the datum and must remain within the certified forward and aft limits throughout the flight.

An imaginary vertical reference plane from which all longitudinal distances for mass and balance calculations are measured. It is fixed by the manufacturer and may lie ahead of, within, or behind the aircraft.

The horizontal distance from the datum to the centre of gravity of an item or of the whole aircraft, measured parallel to the aircraft's longitudinal axis. It is multiplied by mass to give the moment.

Another name for the balance arm, being the perpendicular distance from the datum to the line of action of a weight. It determines how strongly a given mass shifts the aircraft centre of gravity.

The product of a mass and its balance arm, expressing the turning effect of that mass about the datum. Summing moments and dividing by total mass gives the aircraft centre of gravity position.

The forward and aft boundaries of centre of gravity position approved for the aircraft, usually narrowing with increasing mass. Operating outside them invalidates the certificate of airworthiness and may make the aircraft uncontrollable.

The most forward centre of gravity position permitted, set mainly by elevator authority for rotation and landing flare and by nose-wheel loading. Exceeding it forward can make rotation and flare impossible.

The most rearward centre of gravity position permitted, set mainly by longitudinal stability and control. Exceeding it aft reduces static stability and can cause difficulty recovering from a stall or upset.

The chord of an equivalent rectangular wing producing the same aerodynamic characteristics as the actual wing. Centre of gravity position is often expressed as a percentage of mean aerodynamic chord for the operator's trim sheet.

A document showing the aircraft's dry operating mass, traffic load distribution, fuel, take-off mass, landing mass, and centre of gravity position, certified by the person responsible for loading control before departure.

A worksheet or table used to calculate the final centre of gravity position from the distribution of mass in holds and cabin, often expressed as a percentage of mean aerodynamic chord, and to confirm it lies within limits.

An alteration to load after the load sheet has been completed, such as an added or offloaded passenger or bag. It must be assessed for mass and CG effect and recorded on the load sheet before departure.

A scaled, simplified number representing a moment, used so that load sheets can be completed with small numbers rather than large moment values. Index units are converted back to a CG position using the operator's table.

The maximum mass per unit area that a cargo compartment floor may carry, expressed in kilograms per square metre. Exceeding it can cause structural damage even when total mass and CG remain within limits.

The arrangement of passengers, baggage, cargo, and fuel in their assigned positions so that mass limits, floor limits, and CG limits are all satisfied. Poor distribution can breach limits despite an acceptable total mass.

The moment produced by the mass of fuel in each tank at its balance arm. Because fuel burns during flight, the total moment and therefore the CG position change continuously, so both take-off and landing cases must be checked.

A prescribed mass value used for passengers and baggage when actual masses are not determined, such as 84 kg per adult passenger in some regulations. It simplifies load sheets but introduces an accepted uncertainty.

The load sheet, trim sheet, and associated records that show the aircraft was loaded within approved mass and CG limits. These documents must be retained and made available for inspection as required by the authority.

The tendency of an aircraft to return to its original flight condition after a disturbance. It depends strongly on CG position: a forward CG increases stability and pitch-down tendency, while an aft CG reduces stability.

The airspeed at which the wing reaches its critical angle of attack. It increases with aircraft mass, so a heavier aircraft stalls at a higher speed and requires longer take-off and landing distances.