Skip to content
PilotSchool Knowledge Base

Understanding Weight and Balance Terminology

Introduction

Understanding weight and balance terminology is fundamental for safe flight operations. Ensuring that an aircraft operates within its weight and balance limits is crucial for maintaining stability, control, and compliance with aviation regulations. This section covers key terms related to weight and balance, essential for the RPL theory exam.

Key Terms

Operating Weight

Operating weight refers to the aircraft’s total weight, including its basic empty weight, crew, passengers, baggage, and operational items, excluding usable fuel.

Zero Fuel Weight (ZFW) and Maximum Zero Fuel Weight (MZFW)

  • Zero Fuel Weight (ZFW): The weight of the aircraft with its contents and crew, excluding usable fuel. It is critical for weight and balance calculations and determining allowable fuel amounts to remain within structural and performance limits. Source: GlobeAir

  • Maximum Zero Fuel Weight (MZFW): The structural limit that ensures safety by preventing excessive stress on the aircraft’s frame; it dictates the maximum weight without usable fuel. Source: Aviation Stack Exchange

Empty Weight

Basic empty weight includes the aircraft’s weight with installed equipment, but without occupants, baggage, or usable fuel. It serves as the foundation for further weight and balance calculations. Source: CASA

Centre of Gravity and Limits

  • Centre of Gravity (CG): The point at which an aircraft’s total weight is considered to be concentrated, crucial for stability and control. Source: NASA

  • CG Limits: The fore and aft boundaries within which the CG must remain during flight operations for safe maneuverability. Source: Wikipedia

Moment

Moment is a rotational force resulting from the product of weight and its arm (distance from a datum). It is used to determine if CG is within allowable limits. Source: EFBOne

Maximum Landing Weight (MLW)

MLW is the highest weight at which an aircraft is certified to land. Exceeding this weight can lead to structural issues and excessive landing distance. Source: CASA

Arm

The arm is the horizontal distance from the reference datum to the center of gravity of a load, used to calculate moments. Source: FAA Handbook

Datum

A datum is an imaginary plane from which all horizontal distances for arms are measured. It simplifies weight and balance calculations by providing a constant reference point. Source: FAA

Maximum Takeoff Weight (MTOW)

MTOW is the highest allowable weight at which an aircraft can take off, dictated by structural and aerodynamic considerations. Source: CASA

Station

A station is a specific location along the aircraft’s structure, measured from the datum. It is a key factor in weight and balance calculations, affecting the arm and moment. Source: EAA

Conclusion

A thorough understanding of these weight and balance terms is essential for pilots to ensure safe and compliant flight operations. This knowledge assists in maintaining aircraft within prescribed limits, preserving structural integrity, and optimizing performance.