Empty weight is the total weight of an aircraft in its baseline, ready-to-fly condition, excluding fuel, payload, and crew.
How It Works#
Empty weight includes the airframe, engines, fixed equipment, and all fluids necessary for operation (such as engine oil and hydraulic fluid). Think of it as the aircraft's "bare minimum" weight before anyone or anything is added. Manufacturers establish this figure during the production process and record it in the aircraft's weight and balance documentation.
Two related terms appear in this context. Basic empty weight (BEW) includes unusable fuel and full operating fluids. Standard empty weight excludes optional equipment. Most modern aircraft documentation uses basic empty weight as the standard baseline.
Empty weight is the starting point for all weight and balance calculations. Pilots add the weight of usable fuel, crew, passengers, and baggage on top of it. The result is the aircraft's gross weight, which must stay within the manufacturer's certified limits for safe flight.
Example in Aviation#
A Cessna 172S has a published basic empty weight of approximately 1,663 lb. Before a training flight, the instructor adds:
- Two occupants at 340 lb combined
- Baggage at 20 lb
- Usable fuel (53 gallons) at 318 lb
The total gross weight comes to roughly 2,341 lb. The 172S's maximum takeoff weight is 2,550 lb, so the aircraft is within limits. Without a known, accurate empty weight, this calculation would be meaningless.
Why It Matters#
Empty weight is not just a number on a form. It is the foundation of every weight and balance calculation a pilot performs. An incorrect empty weight leads to incorrect loading calculations, which can shift the center of gravity outside safe limits or push the aircraft over its maximum takeoff weight.
Empty weight also changes over time. Repairs, added avionics, or paint can all increase it. Regulations require periodic re-weighing to keep records accurate. Pilots should verify the empty weight in the current weight and balance document before relying on older figures.
Key Takeaways#
- Empty weight is the aircraft's weight without usable fuel, payload, or crew.
- It includes the airframe, engines, fixed equipment, and operating fluids.
- Basic empty weight is the standard baseline used in most modern documentation.
- All gross weight and center of gravity calculations start from empty weight.
- Empty weight can change over time and must be kept current in aircraft records.