Brazilian Air Force aircraft structural integrity program: an overview

BackgroundAerobatic flight maneuvers expose military pilots to a confluence of physiological and psychological stressors—including sustained G-forces, vestibular disorientation, and neuromuscular fatigue—that may acutely modulate emotional states and compromise cognitive performance. However, the differential psychometric impact of routine operational flights versus high-intensity air demonstrations remains poorly characterized.PurposeTo examine and compare mood state fluctuations elicited by distinct aerial mission profiles—operational maintenance (OM) flights and aerobatic demonstrations (AD)—within a specialized military pilot cohort.MethodsIn this within-subject, crossover experimental design, nine elite male aviators (mean age: 32.1 ± 1.8 years) from the Brazilian Air Force Air Demonstration Squadron (EDA), each with >1,000 cumulative flight hours, were assessed across two mission contexts. Mood states were measured pre- and post-flight using the Brunel Mood Scale (BRUMS), which evaluates six psychological dimensions: tension, depression, anger, vigor, fatigue, and confusion. Paired comparisons were conducted using the Wilcoxon signed-rank test (α = 0.05).ResultsOM flights were associated with a statistically significant increase in depression scores post-flight (p = 0.031), alongside a non-significant trend toward decreased tension (p = 0.098). Other subscales showed no statistically significant variation, though intra-individual variability was observed.ConclusionEmotional reactivity among high-performance military pilots varies according to mission typology. Incorporating continuous affective monitoring and routine psychological assessments may bolster both operational readiness and mental health preservation in high-demand aviation environments.

The importance of predicting the durability and damage tolerance capability of aircraft structures has underscored the need to derive a realistic flight-by-flight stress spectrum. This stress spectrum is generated from an analysis of the projected usage (mission profiles), combined with load factor exceedance curves that are obtained either from MIL-A-8866B or recorded data. The mission profiles are defined by the using command (the organization which flies the aircraft) and contain such information as mission length, number of times flown per aircraft lifetime, fuel load, weapons configuration, and a breakdown of the mission by segment, for example, takeoff, climb, cruise, descent, etc. This paper describes two different approaches for obtaining load factor exceedance curves: (1) MIL-A-8866B and (2) data recorded from a different aircraft flying a similar mission. In the first example, the spectrum is derived for a ground-attack fighter that is in the design phase (that is, has never flown) and in the second case, the spectrum is derived for an aircraft that has already been built but is being used in a new mission (flight demonstration squadron). In this second case, a large amount of recorded load factor exceedance data exists from a different aircraft flying the same mission. Using either exceedance curve approach, these data are combined with the mission profile data to develop a stress-exceedance curve for each mission. The stress-exceedance information then is input to a computer program, along with some additional data such as the number of times a given mission is flown. The computer program first generates a random mission ordering and then randomly orders the stresses within each mission. The final result is a random flight-by-flight stress spectra suitable for use in performing damage tolerance and durability analyses and tests.

An increasing number of platforms are reaching their design life. For various reasons these platforms will require an assessment of their structural integrity. As examples one may experience operational changes of the platform that may lead to increased loads or there may be damages that reduce the structural capacity. Consequently, the design premises may have changed significantly and may result in increased uncertainty about the safety of the structure. In such cases the assessment process is focused towards reassuring that the structure has adequate safety. When performing these assessments the engineer is faced with tasks where little guidance is found in design standards and the analyses that are required are often based on advanced techniques and methodology that seldom is used in design of new structures. The cost of doing advanced analysis is relatively low compared to replacement of an existing structure, but relatively high compared to moderate additions of e.g. steel in the design of a new structure. Design standards are based on theories, methods and experience for structures in a given design life (e.g. fatigue design and corrosion protection design). When this design life is extended, sound methods for ensuring that the structures are still sufficient safe is needed. Such methods will normally be "condition based design", where inspection, maintenance and repairs are included in the assessment in integrated way. This paper discuss the overall assessment process for life extension and outline procedures connected to how to deal with the specific aspects that engineers meet when performing assessment for structural life extension.

Oil and natural gas producers continuously strive to control costs, and that goal becomes even more important when market conditions are challenging. To maximize the return on their capital investment and continue to extract reserves on legacy fields, many owners and operators are looking for ways to extend the service lives of aging assets. The Neptune Spar was the first production spar platform in the world, when it was installed in 1996. Currently owned and operated by Noble Energy, the unit continues producing at Viosca Knoll 826 in the Gulf of Mexico. As the platform ages, there is an interest in extending its service life to allow continued operation in the field. As requested by Noble Energy, ABS Group initiated a life extension assessment project. This paper describes the process of the Neptune Spar life extension assessments and challenges encountered during the process. One of the critical aspects of the life extension process is regulatory approval. Since the life extension for floating production platforms is a relatively new trend in the offshore industry, the regulatory compliance process is still under development, and this project is providing a significant contribution to the development of guidance and criteria. The purpose of a life extension assessment is to understand the history of the facility and its current physical condition to determine its structural integrity and outline what is needed for the unit to be maintained for safe and responsible extended service. The life extension project began with a roadmap for life extension assessments that included conducting baseline inspections, reviewing historic inspection and repairs records, undergoing gap analyses that compared the spar's current condition with the original design premise and calculations, and performing additional engineering analyses. As part of the regulatory approval process, the U.S. Bureau of Safety and Environmental Enforcement (BSEE) and the U.S. Coast Guard (USCG) require that a Certified Verification Agent (CVA) verify the entire process of life extension and submit reports that document findings and recommendations. ABS served as the CVA. During the life extension assessment process, ABS Group and Noble Energy consistently coordinated with ABS, BSEE and USCG. Based on the life extension assessments, ABS has granted class certificate for the life extension of this platform. The process of the spar's life extension assessment provides industry with a better understanding of the technical requirements for life extension of other floating production assets, which will have a long-term impact on future asset integrity management for these types of facilities in deep water.

The integrity of aircraft structures, including forward sections and leading edges of wings are prone to hail ice impact. In the current work, numerical models of hail ice and CFRP panels have been developed using nonlinear finite element code LS-DYNA. The numerical model consists of a target plate with size 300 mm×300 mm×4.65 mm which were impacted by a spherical hail ice of diameter 42.7 mm. The obtained results show good correlations with the results already published in the literature. Based on the confidence obtained, the numerical study was done with different stacking sequences ([0/45/-45/90]s and [0/45/-45/90]3s) under different impact velocities. It was observed that the inter laminar shear strain energy formed during impact is related to the failure threshold energy of the target plate. It was found that the energy absorption is higher at low impact velocities and tends to steadily decline as the impact velocity increases.

This article analyzes topics concerning the strategic planning of the defense sector and of the Brazilian Air Force, as an argument that, contradicting the axioms, it would be the strategic thought, and not the juridical methods to control the public administrators’ actions, that may serve as effective tool in the construction of the project for an ideal nation, which does not exist in Brazil yet. Such argument begins with the opposition between the bureaucratic state and the managerial state, to, afterwards, revisit the renowned bibliography of strategic planning, obtaining by this way the seals of the sketch to the strategic planning that it is intended to be made. Once the theoretical recital was accomplished, and discussed the strategic orientation formulated according to Ansoff (1983) and Porter´s (1989) assumptions, the conclusions are presented, assuming that the country – in the aeronautical and aerospacial sectors – may have lost part of the superiority formerly conquered, in the pioneers’ times, founders of the Technological Institute of Aeronautics (ITA) and of Embraer. Many variables indicate that great investments in aeronautical and aerospacial technology are still needed in order to accomplish a good surveillance and reconnaissance work for the huge borders, and for the protection of the diversity of Brazilian natural resources.

Many offshore jacket platforms worldwide have approached or exceeded their original design life but are still in use and productive. According to the international codes, standards, and industry best practices, structural assessments of ageing fixed offshore jacket platforms shall be conducted against relevant target values to assess whether it is fit for purpose or risk reduction measures should be considered for continuing its operation. This research examines the collapse behaviour of an ageing offshore jacket platform under extreme storm conditions. Nonlinear collapse analysis has been performed to assess fixed offshore jacket platforms' structural integrity and reliability in shallow water under extreme storm conditions. Two tripods and 4-legged jacket platforms at water depths between 30 to 80 meters, located in the Mahakam Delta, Kalimantan, Indonesia, have been selected in this research as wellhead platform models commonly installed in shallow water. Sensitivity studies examine the effects of pile-soil interaction, variations in pile depth, topside load adjustments, marine growth removal, and jacket strengthening on structural performance. From the structural integrity and reliability perspective, the findings highlight that strengthening the jacket by adding soldier piles is the most effective approach for extending the platform's lifespan, especially for a wave-dominated platform. Additionally, a cost feasibility analysis is advised for future evaluation to determine whether jacket strengthening is viable or if alternative risk reduction strategies should be further explored for the ageing offshore platform.

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The North Sea offshore industry is now over 50 years old with the installation of the first platform in the North Sea in 1966. The majority of platforms have now exceeded their design lives and are considered to be ageing structures in the life-extension phase. Safe operation requires the implementation of structural integrity management systems that recognise the potential issues associated with damage, deterioration and obsolescence. The UK Health and Safety Executive (HSE) Energy Division and Norway’s Petroleum Safety Authority(PSA)have been very active in the development and promotion of good practice in the integrity management of ageing offshore installations from the outset. In the UK, with the transfer of responsibilities from the UK Department of Energy to the HSE following the Piper Alpha disaster of 1988, the HSE has funded a substantial research programme on ageing and life extension (ALE) issues. This has supported the development of codes, standards and guidance on structural integrity management and ageing / life extension. The HSE has under taken major industry-wide inspection programmes and led significant stakeholder engagement activities to promote awareness of ALE within the offshore industry. A particularly successful initiative was the creation of the Energy Institute Ageing and Life Extension Work Group which supports the development of guidance on ALE issues and continues to be very active. Most recently, the HSE has extended its activity to the assessment of extreme weather loading, characterised by the 10,000-year event, which was not a design requirement for ageing installations and now presents a challenge to these. Similarly, PSA in Norway has placed an increasing focus on ageing facilities since the late 1990s. By then, a few fixed offshore platforms had exceeded their original design life but, more significantly, a number of drilling rigs showed signs of ageing and had exceeded their design life. A joint letter to the industry about managing ageing drilling rigs was issued by the HSE in the UK and PSA in Norway in 2003. From 2005 to 2010, PSA undertook a key programme on ageing and life extension of oil and gas facilities. This key programme initiated several technology-development projects with the aim of increasing knowledge in the industry on life extension assessment. This paper outlines the work of the offshore regulatory authorities on the issue of ageing and life extension and concludes that, with the focus on energy transition, ALE will present further challenges to the safe operation of offshore structures for the foreseeable future. The management of ALE in the evolving offshore environment also highlights the importance of suitable integrity management practices and the role of regulation in ensuring workforce safety.

Objective/Scope (25 – 75 word) Existing Fired heaters in Ruwais Train-1/2 are designed and constructed in 1980 and are currently running with low efficiency of ~76%. In addition, fin burning is observed, due to high fin temperature which impairs heaters performance and necessitates replacement. This paper portrays the specific engineering way adopted to revive the performance, improve efficiency & enhance integrity of the existing 40 years old fired heaters. Methods, Procedures, Process (75 – 100 word) Replacing convection section was identified as opportunity to improve & maximize value. Adopting systematic engineering approach, three options (identical, full and partial replacement) were evaluated and best option with maximum benefit was selected as below. Improved tube fin density: Optimum selection of fin density is very crucial not to increase the heater draft at the same time to obtain maximum heat recovery.Enhanced fin material: Existing tube / fins are replaced with CS tubes & 11/13 Cr fins to sustain high temperature & avoid fin burning.Install future tube rows: 2 future tube row space were installed with fin tubes, enhancing heat recovery and reducing flue gas temperature. Results, Observations & Conclusions (100 – 200 words) Thermal design of the heaters confirmed that following enhancements could be realized upon existing heaters upgrade. Support Sustainability by reduction in fuel gas consumption and flue gas emissions by 8 to 10%Efficiency increases as below. Heaters 1 A & B - Increase from 76.4 to 86.1%Heaters 2 A & B - increase from 77 to 86%Heaters 3 A & B - Increase from 73 to 84 %Flue gas temperature leaving the convection section drops down from 460 to 263OC in heater 1 & 527 to 300OC in heater 2.Estimated Reduction in CO2 emission is ~ 54,000 MT/year.Integrity: Enhance integrity and service life of convection section by use of improved convection section tube material and improved tube fin material 11/13 Cr for selected rows.Foundation: No impact on foundation as increase in weight of the heater <1%Performance: Proposed new convection section design enables the furnace to be operated at its design duty by avoiding burning of fins with use of enhance fin material.Profitability: Cost savings of USD 39.5M for a design life of 15 years for 4 heaters due to reduction in fuel gas Novel/Additive Information (25 – 75 words) Strengthening the aging facilities is crucial to ensure its integrity, life extension and facility performance. However, the benefits are doubled when the asset life extension actions are resulting in enhancement of efficiency, performance & cost saving for the extended life. Asset life extension can earn to operating companies, when escorted with smart enhancements supported by latest technics and careful selections.

Low-yield-strength (LYS) steels possess ultra-high ductility and low yield ratio which indicates a wide prospect of the application for energy absorption. When a LYS steel-based damper or buffer is activated by a seismic wave or a crash impact, the structural integrity usually has a high risk of failure. Hence, the fracture resistance of LYS steels should be a key parameter for their structural design and integrity assessment. Here, we report both an experimental and a numerical investigation on the fracture behavior of an LYS steel with the yield stress of 100 MPa (LYS100), where a part-through corner or surface crack is machined in specimens and the critical loading capacities of the specimens are determined by our experiments. The suitable material parameters of the extended finite element method for LYS100 are determined based on our experimental results, which can be used to describe the fracture behavior of LYS100. Our results show that the fracture toughness of LYS100 can be up to around 1019 N/mm, which is almost twice as high as that of Q235 and one order bigger than that of gray cast iron. These findings will be a great help toward understanding the fracture properties of LYS steels and designing high-performance damping structures.

Corrosion is one of the damage mechanisms affecting the structural integrity of aging aircraft structures. Various nondestructive inspection (NDI) techniques are being used to obtain images of corroded regions on structures. A computational approach using wavelet transforms and artificial neural networks to analyze and quantify the extent of corrosion damage from the NDI images is described. The wavelet parameters obtained from the images were first used to classify between corroded and uncorroded regions using a clustering algorithm. The corroded regions were further analyzed to obtain the material loss due to corrosion using an artificial neural network model. Experiments were carried out to investigate the developed methods for aircraft panels with engineered corrosion obtained from the Federal Aviation Administration Validation Center in Albuquerque. The results presented indicate that the computational methods developed for corrosion analysis seem to provide reasonable results for estimating material loss due to corrosion damage.

A numerical study into the dynamic behaviour of hybrid pressurised barrels manufactured from GLARE (Glass fibre Reinforced laminate) has been performed using the Arbitrary-Lagrangian-Eulerian (ALE) method that accounts for fluid structure interaction within the explicit finite element software RADIOSS. The results high-lighted the importance of the geometrical features of the closed barrel when assessing the shock wave propagation of the blast wave. Also the effect of pre-pressurisation was studied which proved significant in providing additional internal energy to the system. It was concluded that pressurisation should be accounted in all future studies to model the dynamic crack growth and structural integrity of typical aircraft structures subjected to blast.

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Hidden corrosion in aircraft structures, not detected on time, can have a significant influence on aircraft structural integrity and lead to catastrophic consequences. According to the widely accepted damage tolerance philosophy, non-destructive inspections are performed to assess structural safety and reliability. One of the inspection techniques used for such an inspection is the optical D-Sight technique. Since D-Sight is used primarily as a qualitative method, it is difficult to assess the evolution of a structural condition simply by comparing the inspection results. In the following study, the method to monitor hidden corrosion growth is proposed on the basis of historical data from D-Sight inspections. The method is based on geometric transforms and segmentation techniques to remove the influence of measurement conditions, such as the angle of observation or illumination, and to compare corroded regions for a sequence of D-Sight images acquired during historical inspections. The analysis of the proposed method was performed on the sequences of D-Sight images acquired from inspections of Polish military aircraft in the period from 2002 to 2017. The proposed method represents an effective tool for monitoring hidden corrosion growth in metallic aircraft structures based on a sequence of D-Sight images.