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Software
Published in Mike Tooley, Aircraft Digital Electronic and Computer Systems, 2023
Post-certificate modification of equipment in the catastrophic, hazardous or major categories (Levels A, B and C, see Tables 13.1 and 13.2) must not be made unless first approved by the DO. Hence all software upgrades and modifications are subject to the same approval procedures as are applied to hardware modifications. This is an important point that recognises the importance of software as an ‘aircraft part’. Any modifications made to software must be identified and controlled in accordance with the CMP. Guidance material is provided DO-178B/ED-12B and DO-178C/ED-12C (2011).The relationship between the development of aircraft hardware and software is shown in Figure 13.2. Note that the two life cycles (hardware and software) are closely interrelated simply because a change in hardware configuration inevitably requires a corresponding change to the software configuration. The safety assessment process (SAP) is a parallel activity to that of the system development process. It is important to be aware that changes to the system design and configuration will always necessitate a re-appraisal of safety factors.
Advanced predictive quality adjustment strategy for aircraft parts
Published in Lin Liu, Automotive, Mechanical and Electrical Engineering, 2017
Fang Zhu, Xiongfei Huang, Na Wei, Baoyu Ye
In Formula (1) above, XM(k) corresponds to the quality characteristic vector of the aircraft part with deviation at station k. Y(k) corresponds to the measured data of the aircraft part quality property at station k. XM(k–1) corresponds to the quality characteristic vector with deviation at station k–1. AkXM(k–1) corresponds to the transformation of quality characteristic from station k–1 to station k. Xp’(k) is the latest fabricated quality characteristic vector at station k. BkXp’(k) corresponds to the effect that the process deviations affect the aircraft part quality characteristic at station k. wk and vk are different types of noise. wk corresponds to the noise affected on the aircraft part at station k. vk corresponds to the measurement noise at station k.
The Development of Mental Health Proxy Teams and a Relationship That Threatened the Quality of a Safety Investigation
Published in Nektarios Karanikas, Maria Mikela Chatzimichailidou, Safety Insights, 2020
John was involved in an aircraft accident, where he was the pilot. When I first heard it on the radio, I froze because I thought “John is gone”. However, the situation was a bit more complicated, and, gratefully, John was still alive. That Wednesday morning, John was scheduled for a certification renewal flight, and he was flying with another highly experienced pilot in the cockpit. The thrill of the moment caught John, and he wanted to take some cool photos of the sunset near the mountains south of the airport, close to the sea. And there was where the problems began. The photo-making was a last-minute decision during the flight. The crew did not have enough time to plan a new course, put new stirring points, and check all maps in detail. It was common knowledge that those mountains have high voltage cables at a high altitude. John wanted to take a cool shot of the sunset while “knifing” the aircraft between two mountaintops. So, as he was passing through, he chipped off one-third of his left wing due to contact with a high voltage cable in the area. That aircraft part was shot out at the nearby beach and ended in the sea. He managed to level off and do an emergency landing at a nearby small airport. Any substantiated doubts of the crew about the existence of the cables and the exact sequence of decisions and actions before and after the accident remain yet blurred. In my mind, I was vouching for the middle truth; John began the knifing to avoid the cables at the last moment, while he was flying low, almost at the lowest permittable limit (300ft). This underlines how positively I was predisposed towards John.
Synergistic effect of pH and oxalate concentration on corrosion of aluminium alloy 2024-T3
Published in Corrosion Engineering, Science and Technology, 2018
Alexander Hoyt, Shengxi Li, Xinyan Dai, Camila Garcia, Hongbo Cong, Bi-min Zhang Newby
Aluminium alloys have been widely utilised as the primary structural material for aircraft parts because of their excellent strength to weight ratio and fatigue resistance. Their thin native oxide film serves as a barrier, providing good corrosion resistance in neutral solutions (pH: 4.0–8.5) at room temperature. Heavy corrosion of aluminium alloys has been observed in more acidic or alkaline media [1]. Their susceptibility to corrosion is affected by the growth or dissolution of oxide layer when exposed to aqueous environment. Extensive research has been conducted on the corrosion behaviour of aluminium alloys, including alloy AA2024-T3, in various aggressive electrolytes such as salts [2–4], alkalis [5] and acids [6,7].