5. Balance calculation methods............................................................................................280
5.1. Introduction................................................................................................................280
5.2. Manual balance calculation method...........................................................................280
5.3. EDP balance calculation methods 288
A. CARGO SYSTEMS
SYSTEMS
SYSTEMS
CARGO SYSTEMS INTRODUCTION
Airbus aircraft are designed for passenger civil air transport with a passenger cabin on the upper deck. The lower deck of the airplane is dedicated to passenger luggage as well as additional freight transportation. So at the end of the 60‘s, the A300 was originally designed to accommodate, with a semi-automatic, electrically powered cargo loading system, the Unit Load Devices that were already standardized at that time for the B747, considering that the cargo area was too great for it to be loaded manually. This solution was later used for to all the other long-range programs. On the single aisle family two cargo loading solutions are proposed to the operators either manual bulk loading or semi-automatic, electrically powered cargo loading system accommodating Unit Load Devices derived from the larger aircraft ULDs. The following chapter describes the cargo loading areas on Airbus aircraft and the systems related to cargo holds. As an introduction the first paragraph is dedicated to Unit Load Devices description.
A. CARGO SYSTEMS
A. CARGO SYSTEMS
1. TYPE OF ULDS AND CONFIGURATION
1.1. History
When the first Boeing 747 went into service in 1970, the air transport industry faced a dramatic change of ground-handling culture. In fact, the lower-deck capacity of the 747 was too great for it to be loaded manually. Baggage and cargo had to be accommodated in Unit Load Devices (ULDs), which had previously only been used for freighter aircraft. The 747 was originally designed to accommodate the 96in square cross-section of the ISO standard ”marine‘ containers on the main deck, which determined the overall shape and size of the fuselage. The space remaining in the lower deck, after satisfying the main deck requirement determined the basic dimensions and shape of the lower-deck containers. Most carriers at that time used 88in x 125in pallets on freighter aircraft. The 747s lower-deck system was required, therefore, to be able to accept the 125in dimension across the width of the lower deck. Then the lower deck height dictated the maximum height for ULDs (64in). For ease of handling, the new baggage containers were smaller than cargo containers and were loaded in pairs, each unit occupying half the width of the compartment floor. The baseplate dimensions of the half-width container were set at 60.4 x 61.5in. Having been of such service to the industry in developing a ”standard‘ for lower deck ULD equipment, Boeing then, unaccountably, introduced the 767, which first flew in 1981, which used several completely different sizes of ULD. With this background of evolution and airframe manufacturer influence, although many of the ULD sizes in use are ”standard‘ in terms of certain critical dimensions, incompatibilities do still exist and many different ULD types are in service. The basic reference document for ULD base sizes is a National Aerospace Standard produced by the Aerospace Industries Association of America, in accordance with the requirements of federal Aviation Regulation-Part25 (FAR25)-Airworthiness Standards: Transport Category Aeroplanes. This document, drafted with input from the major U.S. airframe manufacturers, was designated NAS3610. The document was approved by the Federal Aviation Administration (FAA) in 1969 and entitled: minimum Airworthiness requirements and test conditions for Certified Air Cargo Unit Load devices. The primary objective was to provide requirements designed to ensure the ability of ULDs and their in-aircraft restraint-systems to contain their load under the influence of in-flight forces. Although NAS3610 is an airworthiness certification document, the fact that it reflects mandatory requirements and details the baseplate dimensions of all ULDs types dictate that all ULD standards should refer to it. NAS3610 only considers the ULD baseplate. There are a variety of different contours that may be attached to any one baseplate size. It is the responsibility of the owner of an aircraft ULD to have provisions for the maintenance of such units to the effect that they are kept in an airworthy condition. Airbus does not differentiate between so-called certified or non-certified containers. It is not required that a container actually undergoes a certification process, however the container has to fulfil the same requirements as a certified container.
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