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Douglas D Boyd - One of the best experts on this subject based on the ideXlab platform.
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causes and risk factors for fatal accidents in non commercial twin Engine piston general aviation aircraft
Accident Analysis & Prevention, 2015Co-Authors: Douglas D BoydAbstract:Accidents in twin-Engine aircraft carry a higher risk of fatality compared with single Engine aircraft and constitute 9% of all general aviation accidents. The different flight profile (higher airspeed, service ceiling, increased fuel load, and aircraft yaw in Engine Failure) may make comparable studies on single-Engine aircraft accident causes less relevant. The objective of this study was to identify the accident causes for non-commercial operations in twin Engine aircraft. A NTSB accident database query for accidents in twin piston Engine airplanes of 4-8 seat capacity with a maximum certified weight of 3000-8000lbs. operating under 14CFR Part 91 for the period spanning 2002 and 2012 returned 376 accidents. Accident causes and contributing factors were as per the NTSB final report categories. Total annual flight hour data for the twin Engine piston aircraft fleet were obtained from the FAA. Statistical analyses employed Chi Square, Fisher's Exact and logistic regression analysis. Neither the combined fatal/non-fatal accident nor the fatal accident rate declined over the period spanning 2002-2012. Under visual weather conditions, the largest number, n=27, (27%) of fatal accidents was attributed to malfunction with a Failure to follow single Engine procedures representing the most common contributing factor. In degraded visibility, poor instrument approach procedures resulted in the greatest proportion of fatal crashes. Encountering thunderstorms was the most lethal of all accident causes with all occupants sustaining fatal injuries. At night, a Failure to maintain obstacle/terrain clearance was the most common accident cause leading to 36% of fatal crashes. The results of logistic regression showed that operations at night (OR 3.7), off airport landings (OR 14.8) and post-impact fire (OR 7.2) all carried an excess risk of a fatal flight. This study indicates training areas that should receive increased emphasis for twin-Engine training/recency. First, increased training should be provided on single Engine procedures in the event of an Engine Failure. Second, more focus should be placed on instrument approaches and recovery from unusual aircraft attitude where visibility is degraded. Third, pilots should be made aware of appropriate speed selection for inadvertent flights in convective weather. Finally, emphasizing the importance of conducting night operations under instrument flight rules with its altitude restrictions should lead to a diminished proportion of accidents attributed to Failure to maintain obstacle/terrain clearance. Language: en
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causes and risk factors for fatal accidents in non commercial twin Engine piston general aviation aircraft
Accident Analysis & Prevention, 2015Co-Authors: Douglas D BoydAbstract:Accidents in twin-Engine aircraft carry a higher risk of fatality compared with single Engine aircraft and constitute 9% of all general aviation accidents. The different flight profile (higher airspeed, service ceiling, increased fuel load, and aircraft yaw in Engine Failure) may make comparable studies on single-Engine aircraft accident causes less relevant. The objective of this study was to identify the accident causes for non-commercial operations in twin Engine aircraft. A NTSB accident database query for accidents in twin piston Engine airplanes of 4-8 seat capacity with a maximum certified weight of 3000-8000lbs. operating under 14CFR Part 91 for the period spanning 2002 and 2012 returned 376 accidents. Accident causes and contributing factors were as per the NTSB final report categories. Total annual flight hour data for the twin Engine piston aircraft fleet were obtained from the FAA. Statistical analyses employed Chi Square, Fisher's Exact and logistic regression analysis. Neither the combined fatal/non-fatal accident nor the fatal accident rate declined over the period spanning 2002-2012. Under visual weather conditions, the largest number, n=27, (27%) of fatal accidents was attributed to malfunction with a Failure to follow single Engine procedures representing the most common contributing factor. In degraded visibility, poor instrument approach procedures resulted in the greatest proportion of fatal crashes. Encountering thunderstorms was the most lethal of all accident causes with all occupants sustaining fatal injuries. At night, a Failure to maintain obstacle/terrain clearance was the most common accident cause leading to 36% of fatal crashes. The results of logistic regression showed that operations at night (OR 3.7), off airport landings (OR 14.8) and post-impact fire (OR 7.2) all carried an excess risk of a fatal flight. This study indicates training areas that should receive increased emphasis for twin-Engine training/recency. First, increased training should be provided on single Engine procedures in the event of an Engine Failure. Second, more focus should be placed on instrument approaches and recovery from unusual aircraft attitude where visibility is degraded. Third, pilots should be made aware of appropriate speed selection for inadvertent flights in convective weather. Finally, emphasizing the importance of conducting night operations under instrument flight rules with its altitude restrictions should lead to a diminished proportion of accidents attributed to Failure to maintain obstacle/terrain clearance.
R Mackay - One of the best experts on this subject based on the ideXlab platform.
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optimization of the solution heat treatment process to improve mechanical properties of 319 al alloy Engine blocks using the billet casting method
Materials Science and Engineering A-structural Materials Properties Microstructure and Processing, 2015Co-Authors: A Lombardi, C Ravindran, R MackayAbstract:Abstract The use of Al Engine blocks has increased significantly to improve vehicle fuel efficiency. However, the large tensile residual stress along the cylinder bores necessitates the optimization of mechanical properties in this region to prevent premature Engine Failure. This study, utilizing billet castings which replicate the microstructure along the Engine cylinder bores, observed the influence of varying solution heat treatment parameters on microstructure and mechanical properties. Microstructural analysis was carried out on the billet castings using optical microscopy, SEM and EDX, while mechanical properties were assessed using tensile testing. The results suggest that the optimal solution heat treatment parameters, resulting in the most effective Al2Cu dissolution and largest increase in tensile properties for all the replicating billet castings, were at 500 °C for 2 h. In addition, solutionizing at 515 and 530 °C, although more effective in dissolving Al2Cu, resulted in incipient melting of Al2Cu and Al5Mg8Cu2Si6, which deteriorated the tensile properties. The results from this study will assist in the development and implementation of an optimized heat treatment schedule, preventing in-service Engine Failure and improving process efficiency.
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replication of Engine block cylinder bridge microstructure and mechanical properties with lab scale 319 al alloy billet castings
Materials Characterization, 2014Co-Authors: A Lombardi, Francesco Delia, C Ravindran, R MackayAbstract:Abstract In recent years, aluminum alloy gasoline Engine blocks have in large part successfully replaced nodular cast iron Engine blocks, resulting in improved vehicle fuel efficiency. However, because of the inadequate wear resistance properties of hypoeutectic Al–Si alloys, gray iron cylinder liners are required. These liners cause the development of large tensile residual stress along the cylinder bores and necessitate the maximization of mechanical properties in this region to prevent premature Engine Failure. The aim of this study was to replicate the Engine cylinder bridge microstructure and mechanical properties following TSR treatment (which removes the sand binder to enable easy casting retrieval) using lab scale billet castings of the same alloy composition with varying cooling rates. Comparisons in microstructure between the Engine block and the billet castings were carried out using optical and scanning electron microscopy, while mechanical properties were assessed using tensile testing. The results suggest that the microstructure at the top and middle of the Engine block cylinder bridge was successfully replicated by the billet castings. However, the microstructure at the bottom of the cylinder was not completely replicated due to variations in secondary phase morphology and distribution. The successful replication of Engine block microstructure will enable the future optimization of heat treatment parameters.
A Lombardi - One of the best experts on this subject based on the ideXlab platform.
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optimization of the solution heat treatment process to improve mechanical properties of 319 al alloy Engine blocks using the billet casting method
Materials Science and Engineering A-structural Materials Properties Microstructure and Processing, 2015Co-Authors: A Lombardi, C Ravindran, R MackayAbstract:Abstract The use of Al Engine blocks has increased significantly to improve vehicle fuel efficiency. However, the large tensile residual stress along the cylinder bores necessitates the optimization of mechanical properties in this region to prevent premature Engine Failure. This study, utilizing billet castings which replicate the microstructure along the Engine cylinder bores, observed the influence of varying solution heat treatment parameters on microstructure and mechanical properties. Microstructural analysis was carried out on the billet castings using optical microscopy, SEM and EDX, while mechanical properties were assessed using tensile testing. The results suggest that the optimal solution heat treatment parameters, resulting in the most effective Al2Cu dissolution and largest increase in tensile properties for all the replicating billet castings, were at 500 °C for 2 h. In addition, solutionizing at 515 and 530 °C, although more effective in dissolving Al2Cu, resulted in incipient melting of Al2Cu and Al5Mg8Cu2Si6, which deteriorated the tensile properties. The results from this study will assist in the development and implementation of an optimized heat treatment schedule, preventing in-service Engine Failure and improving process efficiency.
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replication of Engine block cylinder bridge microstructure and mechanical properties with lab scale 319 al alloy billet castings
Materials Characterization, 2014Co-Authors: A Lombardi, Francesco Delia, C Ravindran, R MackayAbstract:Abstract In recent years, aluminum alloy gasoline Engine blocks have in large part successfully replaced nodular cast iron Engine blocks, resulting in improved vehicle fuel efficiency. However, because of the inadequate wear resistance properties of hypoeutectic Al–Si alloys, gray iron cylinder liners are required. These liners cause the development of large tensile residual stress along the cylinder bores and necessitate the maximization of mechanical properties in this region to prevent premature Engine Failure. The aim of this study was to replicate the Engine cylinder bridge microstructure and mechanical properties following TSR treatment (which removes the sand binder to enable easy casting retrieval) using lab scale billet castings of the same alloy composition with varying cooling rates. Comparisons in microstructure between the Engine block and the billet castings were carried out using optical and scanning electron microscopy, while mechanical properties were assessed using tensile testing. The results suggest that the microstructure at the top and middle of the Engine block cylinder bridge was successfully replicated by the billet castings. However, the microstructure at the bottom of the cylinder was not completely replicated due to variations in secondary phase morphology and distribution. The successful replication of Engine block microstructure will enable the future optimization of heat treatment parameters.
C Ravindran - One of the best experts on this subject based on the ideXlab platform.
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optimization of the solution heat treatment process to improve mechanical properties of 319 al alloy Engine blocks using the billet casting method
Materials Science and Engineering A-structural Materials Properties Microstructure and Processing, 2015Co-Authors: A Lombardi, C Ravindran, R MackayAbstract:Abstract The use of Al Engine blocks has increased significantly to improve vehicle fuel efficiency. However, the large tensile residual stress along the cylinder bores necessitates the optimization of mechanical properties in this region to prevent premature Engine Failure. This study, utilizing billet castings which replicate the microstructure along the Engine cylinder bores, observed the influence of varying solution heat treatment parameters on microstructure and mechanical properties. Microstructural analysis was carried out on the billet castings using optical microscopy, SEM and EDX, while mechanical properties were assessed using tensile testing. The results suggest that the optimal solution heat treatment parameters, resulting in the most effective Al2Cu dissolution and largest increase in tensile properties for all the replicating billet castings, were at 500 °C for 2 h. In addition, solutionizing at 515 and 530 °C, although more effective in dissolving Al2Cu, resulted in incipient melting of Al2Cu and Al5Mg8Cu2Si6, which deteriorated the tensile properties. The results from this study will assist in the development and implementation of an optimized heat treatment schedule, preventing in-service Engine Failure and improving process efficiency.
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replication of Engine block cylinder bridge microstructure and mechanical properties with lab scale 319 al alloy billet castings
Materials Characterization, 2014Co-Authors: A Lombardi, Francesco Delia, C Ravindran, R MackayAbstract:Abstract In recent years, aluminum alloy gasoline Engine blocks have in large part successfully replaced nodular cast iron Engine blocks, resulting in improved vehicle fuel efficiency. However, because of the inadequate wear resistance properties of hypoeutectic Al–Si alloys, gray iron cylinder liners are required. These liners cause the development of large tensile residual stress along the cylinder bores and necessitate the maximization of mechanical properties in this region to prevent premature Engine Failure. The aim of this study was to replicate the Engine cylinder bridge microstructure and mechanical properties following TSR treatment (which removes the sand binder to enable easy casting retrieval) using lab scale billet castings of the same alloy composition with varying cooling rates. Comparisons in microstructure between the Engine block and the billet castings were carried out using optical and scanning electron microscopy, while mechanical properties were assessed using tensile testing. The results suggest that the microstructure at the top and middle of the Engine block cylinder bridge was successfully replicated by the billet castings. However, the microstructure at the bottom of the cylinder was not completely replicated due to variations in secondary phase morphology and distribution. The successful replication of Engine block microstructure will enable the future optimization of heat treatment parameters.
Daniel Albaladejo Hernandez - One of the best experts on this subject based on the ideXlab platform.
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marine diesel Engine Failure simulator based on thermodynamic model
Applied Thermal Engineering, 2018Co-Authors: Jose Antonio Paga Rubio, F Veragarcia, Jose Hernandez Grau, Jose Munoz Camara, Daniel Albaladejo HernandezAbstract:Abstract The diesel Engine is a widely used machine in naval sector both as a propeller and auxiliary generator sets, being the most critical equipment of vessel platform. Therefore, diesel Engine reliability optimization has a transcendental impact on vessel availability, safety and life cycle costs. This article describes the development of a 4-stroke high speed marine diesel Engine Failure simulator used in military and civil vessels as the main Engine of small patrols and yachts and as an auxiliary genset for larger vessels. Failure simulator is based on a one-dimensional thermodynamic model developed in AVLBoost©, adjusted and validated with experimental data from a real Engine in a test bench. The developed model is able to reproduce with confinable results the effect of a large number of typical thermodynamic Failures, the behavior of the Engine and the effects over several parameters measured and non-measured. Therefore, it is possible to obtain the Engine response to Failures without having to provoke them in real Engine and also it is possible to know the symptoms of one Failure before this Failure becomes dangerous for the correct behavior of the Engine. In addition, this paper exposes a methodology which allows to obtain a Failure simulator of any marine diesel Engine. This simulator is able to identify diesel Engine symptoms under Failure condition and build a reliable Failure database for diagnosis purposes.