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Aircraft load planning and control
Published in Peter J. Bruce, Yi Gao, John M. C. King, Airline Operations, 2018
The maximum weights for each of these configurations (MZFW, MRWT, MTOW, MLDW) are the maximum weights that the manufacturer certifies the aircraft will achieve safe and controllable flight in the hands of a competent pilot. An important part of the Load Control process is to ensure these weight limitations are not exceeded on any flight. In order to achieve this, the weight of passengers, baggage, cargo, fuel, crew, catering, and finally, the weight of the aircraft when empty must be known. Aircraft are weighed at regular intervals as determined by the local regulatory authority, and, together with a mechanism for tracking weight changes resulting from any engineering activities, the aircraft empty weight and CG can be calculated and monitored. If the changes in aircraft empty weight or CG exceed the acceptable figures defined by the operator’s regulatory authority, then new aircraft empty weight documentation must be reissued. This calculation of the aircraft empty weight and CG become the starting point for the calculation of aircraft weight. Note: there are many definitions of aircraft empty weight. Different operators consider different items to be part of the aircraft empty weight, but as a general guide the starting point of Load Control calculations fall into one of two categories – Dry Operating Weight or Basic Weight.
Military Aircraft
Published in G. Daniel Brewer, Hydrogen Aircraft Technology, 2017
For this purpose, payload weight may be thought of as the counterpart of empty weight, i.e., for a given gross weight, as empty weight decreases, payload weight can increase. Therefore, except for SFC, all of these parameters have been mentioned in the foregoing discussion and, with the exception of the limitation on cruise velocity, the advantages afforded by a PAR-WIG aircraft flying in surface effect, relative to corresponding characteristics of conventional-type aircraft, are clear. Two points remain to be made: one relates to the question of how close to the surface of the ocean is it practical for a WIG aircraft to fly in order to realize maximum L/D; the other involves consideration of the use of hydrogen in aircraft of this type and determination of its effect on SFC.
Force-System Resultants and Equilibrium
Published in Richard C. Dorf, The Engineering Handbook, 2018
The empty-weight to maximum gross-weight ratios of aeronautical and space vehicles are critical parameters in their performance and material selection plays a big role in this value. The empty-weight fraction for a flight system is defined as the empty weight, We, divided by the take-off gross weight, Wo. It differs from the dry mass fraction in that it does not include payload since payloads are on the order of 5% to 35% of take-off gross weight. The take-off gross weight (or the maximum gross weight) includes the aircraft’s empty weight, aircraft fuel, and payload.
Closed-loop digital twin system for air cargo load planning operations
Published in International Journal of Computer Integrated Manufacturing, 2021
Eugene Y. C. Wong, Daniel Y. Mo, Stuart So
In a cargo loading plan, a planner needs to decide the position of each ULD in an aircraft, which contains several compartments and components. For the sake of balancing the overall weight of an aircraft, each compartment cannot exceed a certain weight. Apart from this consideration, the space in an aircraft is also divided into several components (Figure 4). CG, which is based on the allocation of ULDs among components, is used to measure the performance of a cargo loading plan. It is defined as the weighted distance value of ULDs from the reference location in each component divided by the total weight of ULDs in an aircraft. It is crucial to include CG in the calculations of the planning tool, not only for safety and regulatory purposes but also for profitability. The closer the actual measured CG to the required limit, the less aircraft fuel will be consumed, leading to cost savings (Vancroonenburg et al. 2013). The aircraft has seven main components: fuel, engines, wings, body, payload, vertical tail and horizontal tail. The CG is determined by dividing the sum of moments of forces by the sum of forces. To calculate it, a reference line is chosen to indicate the reference location of the aircraft components. CG is the mass-weighted average of the component locations. The weight of the entire aircraft times the location of the CG is equal to the sum of the weight of each component times the distance of that component from the reference location (Hall, 2015). The Operational Empty Weight (OEW) equals the cargoless aircraft weight, including staff. The Zero Fuel Weight (ZFW) is calculated as the OEW plus all cargo weight (Vancroonenburg et al. 2011). Figure 5 shows the CG and aircraft components, and Figure 6 gives the floor plan layout of the aircraft, with air cargo loading slots and compartments.