Software verification plan for GCS

This verification plan is written as part of an experiment designed to study the fundamental characteristics of the software failure process. The experiment will be conducted using several implementations of software that were produced according to industry-standard guidelines, namely the Radio Technical Commission for Aeronautics RTCA/DO-178A guidelines, Software Consideration in Airborne Systems and Equipment Certification, for the development of flight software. This plan fulfills the DO-178A requirements for providing instructions on the testing of each implementation of software. The plan details the verification activities to be performed at each phase in the development process, contains a step by step description of the testing procedures, and discusses all of the tools used throughout the verification process

GCS programmer's manual

A variety of instructions to be used in the development of implementations of software for the Guidance and Control Software (GCS) project is described. This document fulfills the Radio Technical Commission for Aeronautics RTCA/DO-178A guidelines, 'Software Considerations in Airborne Systems and Equipment Certification' requirements for document No. 4, which specifies the information necessary for understanding and programming the host computer, and document No. 12, which specifies the software design and implementation standards that are applicable to the software development and testing process. Information on the following subjects is contained: activity recording, communication protocol, coding standards, change management, error handling, design standards, problem reporting, module testing logs, documentation formats, accuracy requirements, and programmer responsibilities

Considerations of Unmanned Aircraft Classification for Civil Airworthiness Standards

The use of unmanned aircraft in the National Airspace System (NAS) has been characterized as the next great step forward in the evolution of civil aviation. Although use of unmanned aircraft systems (UAS) in military and public service operations is proliferating, civil use of UAS remains limited in the United States today. This report focuses on one particular regulatory challenge: classifying UAS to assign airworthiness standards. Classification is useful for ensuring that meaningful differences in design are accommodated by certification to different standards, and that aircraft with similar risk profiles are held to similar standards. This paper provides observations related to how the current regulations for classifying manned aircraft, based on dimensions of aircraft class and operational aircraft categories, could apply to UAS. This report finds that existing aircraft classes are well aligned with the types of UAS that currently exist; however, the operational categories are more difficult to align to proposed UAS use in the NAS. Specifically, the factors used to group manned aircraft into similar risk profiles do not necessarily capture all relevant UAS risks. UAS classification is investigated through gathering approaches to classification from a broad spectrum of organizations, and then identifying and evaluating the classification factors from these approaches. This initial investigation concludes that factors in addition to those currently used today to group manned aircraft for the purpose of assigning airworthiness standards will be needed to adequately capture risks associated with UAS and their operations

The combustion of solid paraffin wax and of liquid glycerol in a fluidised bed

Two fuels were burned in electrically heated beds of alumina sand, fluidised by air. The fuels were: (i) paraffin wax, which is a solid containing 100% volatile matter and (ii) glycerol, a liquid, whose potential as a fuel needs assessing. The bubbling fluidised beds were held in the range 400–900 °C. Pieces of paraffin wax burned like a plastic, so when fed on top of a bed, the wax floated and generated clouds of soot. Soon, it then sank into the bed. When the sand was below ~800 °C, combustion occurred noisily in exploding bubbles leaving the bed. In beds hotter than ~800 °C, combustion proceeded in bubbles fairly low in the bed and was controlled by the mixing of hydrocarbon vapours (from the wax) with the fluidising air. If wax were fed half way up a bed, bubbles of hydrocarbon vapours were quickly produced; they ascended and mixed with the fluidising air. In a bed below 800 °C, combustion mainly occurred noisily in bubbles just after leaving the bed, but in a hotter bed, there was quieter burning in smaller bubbles, before they reached the top of the bed. Glycerol behaved similarly, when fed into the middle of a bed. Thus bubbles of glycerol vapour were formed; they mixed with air ascending the bed as either bubbles or percolating between particles. Again bubbles exploded noisily at the top of a bed below 800 °C. With the bed above 800 °C, glycerol burned inside smaller bubbles below the bed’s upper surface. No soot was observed when burning glycerol in such a hot bed, yielding CO and CO$_2$ as the only products of combustion. It appears that burning glycerol cleanly in a hot fluidised bed is a feasible proposition

Modelling the Risks Remotely Piloted Aircraft Pose to People on the Ground

Worldwide there is much e ort being directed towards the development of a framework of air- worthiness regulations for remotely piloted aircraft systems (RPAS). It is now broadly accepted that regulations should have a strong foundation in, and traceability to, the management of the safety risks. Existing risk models for RPAS operations do not provide a simple means for incorporating the wide range of technical and operational controls into the risk analysis and evaluation processes. This paper describes a new approach for modelling and evaluating the risks associated with RPAS operations near populous areas based on the barrier bow tie (BBT) model. A BBT model is used to structure the underlying risk management problem. The model focuses risk analysis, evaluation, and decision making activities on the devices, people, and processes that can be employed to reduce risk. The BBT model and a comprehensive set of example risk controls are presented. The general model can be applied to any RPAS operation. The foundations for quantitative and qualitative assessments using a BBT model are also presented. The modelling and evaluation framework is illustrated through its application to a case-study rotary wing RPAS for two operational scenarios. The model can be used as a basis for determining airworthiness certification requirements for RPAS

A Review of Current and Prospective Factors for Classification of Civil Unmanned Aircraft Systems

While progress is being made on integrating unmanned aircraft systems (UAS) into our national airspace on a broad scale, much work remains to establish appropriate certification standards and operational procedures, particularly with respect to routine commercial operations. This paper summarizes research to examine the extent to which today's civil aircraft taxonomy applies to UAS, and, if needed, how that taxonomy could be amended to better cover different UAS designs and operations. Factors that shape the current taxonomy, as defined in the Federal Aviation Regulations, were assessed for applicability to UAS, potential incompatibilities were identified, and additional factors were proposed that might be useful for an updated aircraft taxonomy intended to cover UAS. The results suggest the possibility of constructing new groups in the taxonomy for UAS under a restricted category that share common airworthiness standards. Establishing distinct groups for UAS and associated standards that enable low risk operations for compensation or hire could be a timely step toward full integration. Such a step would allow the civil aviation industry and regulators to gain valuable experience with UAS while carefully controlling access and potential harm to the aviation system as a whole