The requirements of the airworthiness of aircraft

Cílem této práce je zjistit požadavky a postupy pro získání a zachování osvědčení letové způsobilosti letadel a výrobků letadlové techniky v rozsahu civilního letectví. Vyšetřované požadavky zahrnují normy týkající se požadavků na letovou způsobilost přes návrh, výrobu a provoz letadlové techniky.The focus of this study is to investigate the requirements and procedures for obtaining and maintaining a certificate of airworthiness of aircraft and aeronautical products within the scope of civil aviation. The requirements investigated include the standards regarding airworthiness requirements for large airplanes, helicopters, small airplanes, engines, and propellers. The procedures for certification and continuing airworthiness throughout the design, production and operating life of an aircraft are explained.

Crashworthiness analysis and enhancement of aircraft structures under vertical impact scenarios

[Abstract:] This research focuses on the crashworthiness study and enhancement of commercial aircraft structures by developing crushable energy absorbers to work as vertical struts. To assess their contribution on a representative crash scenario, a numerical simulation of a Boeing 737-200 drop test developed and verified with experimental data is used as a benchmark. The numerical model is then enhanced with four hybrid energy absorbers designed for programmed and progressive collapse, added in the cargo compartment connecting the underfloor beams and the frames. These devices are composed of a square aluminum tube filled with a composite skeleton and foam extrusions for maximized energy absorption. The enhanced aircraft is later on simulated under hard landing and water ditching scenarios, analyzing the benefits resulting from the absorbers according to structural efficiency and biometric criteria. Results show increased plastic dissipation values by the main structural components given the modified collapse mechanism obtained when adding the crushable absorbers. Peak acceleration values are also reduced, consequently lessening the passenger injury prediction at the studied locations.Ministerio de Economa y Competitividad; DPI2016-76934-RMinisterio de Economía y Competitividad; DPI2016-76934-

Simulation of helicopter ditching using smoothed particle hydrodynamics

This paper explores the potential use of smoothed particle hydrodynamics methods for helicopter ditching. The method appears suitable for this task since it is mesh-free and can accommodate the interaction between a floating object and the free-surface of water. Simple cases of objects dropped on water were first studied to establish confidence on the method, and quantify the effect of the numerical parameters of SPH including the boundary condition between the water and solid, the effect of the number and type of smoothed particles as well as the generation of different sea-states for the ditching. Once confidence on the method was established, experiments for the ditching of a model-scale helicopter were used for validation. The smoothed particle hydrodynamics method provides good agreement with experiential data for the position and velocity of the helicopter fuselage

Crashworthy design and energy absorption mechanisms for helicopter structures: A systematic literature review

Helicopters are versatile aircraft that can perform numerous missions such as ground surveillance, rescue missions, air ambulance, fire-fighting etc. However, helicopter crashes sometimes occur owing to technical failures or human errors. Accordingly, the crashworthy design of helicopters has always remained a top priority to prevent catastrophic structural failure and significant casualties. The crashworthy performance of helicopters can be immensely improved with well-designed energy absorption materials or structures. This paper presents a systematic literature review on crashworthy design and energy absorption mechanisms for helicopter structures. Firstly, the historical development of aircraft crashworthiness investigation at various periods over the past few decades is presented. Then, some typical energy absorbing components such as rings, tubes, honeycombs, corrugated structures and emerging energy absorbers are introduced to act as the major structural elements for the crashworthy design of helicopters. After that, an emphasis is placed on the dynamic behavior and energy absorption of typical helicopter structures such as the landing gear, subfloor, full-scale airframe, helicopter crashworthy seats, fuel tank and helicopter blade. In addition, representative helicopter crash scenarios such as bird strike, water impact and the impact response and injury of the occupants are described. Finally, the crashworthy evaluation criteria of helicopter structures are summarized in this paper. This article is intended as a comprehensive literature review of crashworthy design and impact protection of helicopter structures

Structural response of transport airplanes in crash situations

This report highlights the results of contractural studies of transport accident data undertaken in a joint research program sponsored by the FAA and NASA. From these accident data studies it was concluded that the greatest potential for improved transport crashworthiness is in the reduction of fire related fatalities. Accident data pertaining to fuselage integrity, main landing gear collapse, fuel tank rupture, wing breaks, tearing of tank lower surfaces, and engine pod scrubbing are discussed. In those accidents where the energy absorbing protective capability of the fuselage structure is expended and the airplane experiences major structural damage, trauma caused fatalities are also discussed. The dynamic performance of current seat/restraint systems are examined but it is concluded that the accident data does not adequately define the relationship between occupant response and the dynamic interaction with the seat, floor and fuselage structure

Aeronautical Engineering: A special bibliography with indexes, supplement 74

This special bibliography lists 295 reports, articles, and other documents introduced into the NASA scientific and technical information system in August 1976

Water impact investigations for aircraft ditching analysis

Passenger safety under dynamic crash loading is of key importance in modern aerospace vehicle design. In particular, crash-landings on water, commonly known as ‘ditching’, are a complex event to understand and account for in structural design for crashworthiness. Structural responses are complex and severe, given the highly dynamic nature of the fluid in the impact zone. Through numerical modelling, a better understanding of the dynamics of the event can be gained and thus lead to the development of efficient structural design tools. Of key importance for ditching investigations is the ability of numerical methods to capture the high deformations of the fluid domain in such events. From the various numerical techniques developed thus far, a particular meshfree numerical method has shown great potential to model water impact problems, namely the Smoothed Particle Hydrodynamics (SPH) method. This thesis investigates the SPH capability available in the commercial Finite Element (FE) code LS-DYNA®, for water impact problems. Experiments have been conducted on rigid wedges impacting water, which were then simulated with the SPH method. Although certain limitations were experienced with the experimental results, a positive correlation was observed with the numerical technique, thus establishing SPH as a promising method for crashworthiness design. The direction of further evaluation of the SPH technique has been identified, with the ultimate aim of developing a simulation methodology for the design and advancement of crashworthy concepts for aerospace vehicles

Full-Scale Crash Testing of Transport Rotorcraft

No abstract availabl

Water impact of rigid wedges in two-dimensional fluid flow

A combined experimental and numerical investigation was conducted into impact of rigid wedges on water in two-dimensional fluid conditions. Drop test experiments were conducted involving symmetric rigid wedges of varying angle and mass impacted onto water. The kinematic behaviour of the wedge and water was characterised using high-speed video. Numerical models were analysed in LS-DYNA® that combined regions of Smoothed Particle Hydrodynamics particles and a Lagrangian element mesh. The analysis captured the majority of experimental results and trends, within the bounds of experimental variance. Further, the combined modelling technique presented a highly attractive combination of computational efficiency and accuracy, making it a suitable candidate for aircraft ditching investigations