Refer to figures.
Basic Empty Mass (BEM) is the mass of the helicopter and all its basic equipment and that of the declared quantity of unusable fuel. It also includes any fixed ballast, full operating fluids.

Dry Operating Mass (DOM) is the total mass of the helicopter ready for a specific type of operation excluding all usable fuel and traffic load. This mass includes the items below, known as Variable Load (VL):

• Crew and crew baggage
• Catering and removable passenger service equipment
• Portable water and lavatory chemicals
• Food and beverages
• Rescue hoist/winch
• Cargo sling

Take-Off Mass (TOM) is the mass of a helicopter including everything and everyone contained within it at the start of the take-off run.

Useful Load (UL) consists of the fuel onboard for a flight and traffic load.

Traffic load (TL) in a helicopter refers to the number of passengers or cargo that the aircraft is carrying at a given time. It is used to determine the weight and balance of the helicopter, which is important for safe flight. The maximum traffic load of a helicopter is determined by its design and is specified in its flight manual.

Zero Fuel Mass (ZFM) is the term used to describe the DOM plus TL but excluding usable fuel.

Calculate DOM by:

• DOM = BEM + Crew + Rescue hoist = 5 322 kg + 91 kg + 360 kg
• DOM = 5 773 kg.

NOTE:
The unusable fuel is included in the BEM and therefore, not added again in the calculation.