Definition
The weight of an aircraft including the airframe, engines, all permanently installed equipment, unusable fuel, and full operating fluids (engine oil, hydraulic fluid, and other system fluids required for operation). It does not include usable fuel, payload, or crew.
Plain English
The weight of the aircraft itself with all its built-in equipment and fluids in place, but before adding fuel you can actually burn, passengers, baggage, or cargo.
Context Anchor
Seen in aircraft weight-and-balance records, the Pilot’s Operating Handbook, and loading calculations before a flight.
Derivation
Basic' here means 'the starting baseline.' 'Empty' is slightly misleading — the aircraft is not truly empty. It still contains oil and other operating fluids. The word 'basic' was added to distinguish this figure from older 'empty weight' definitions that excluded full oil.
Why Pilots Care
Knowing the basic empty weight is essential for calculating total takeoff weight and ensuring the aircraft does not exceed its maximum allowable weight.
Analogy
It is like weighing your car with its installed seats, spare tire, and normal fluids, but before adding passengers and luggage for a trip.
Intuition Check
“Empty” does not mean bare, drained, or stripped. Here it means the aircraft before the flight load is added, with installed equipment and required fluids already included.
Example Sentence 1
Before loading passengers and baggage, the pilot started the weight and balance calculation with the basic empty weight from the aircraft's equipment list.
Example Sentence 2
To find the useful load, subtract the basic empty weight from the maximum gross weight.