When is the Basic Weight of an aircraft determined?

The Basic Weight of an aircraft is defined as the weight of the aircraft with all its standard equipment installed, including any optional equipment, and fully fueled for flight. This value is essential for understanding the load capabilities and configurations the aircraft can handle.

The Basic Weight is determined when the aircraft is configured for revenue service, meaning it has reached a state where it is ready to operate commercial flights. At this stage, all necessary equipment, including passenger seating, cargo configurations, and any additional modifications for operational use, are accounted for. This ensures that the Basic Weight reflects the true operational readiness of the aircraft, which is crucial for proper weight and balance calculations, safety assessments, and efficiency in flight operations.

Determining the Basic Weight at other times, such as upon purchase or during routine maintenance, would not provide an accurate representation of the aircraft's true operating condition, as it wouldn’t necessarily include all operational variables present when the aircraft is in service. Similarly, measuring it prior to takeoff would not be appropriate since that weight could fluctuate with added passengers, cargo, and fuel loads that occur right before a flight. Thus, configuring the aircraft specifically for revenue service is the correct context for establishing its Basic Weight.