Matching Items (8)

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Comparison of commercial aircraft fuel requirements in regards to FAR, Flight Profile Simulation, and Flight Operational Techniques

Description

There are significant fuel consumption consequences for non-optimal flight operations. This study is intended to analyze and highlight areas of interest that affect fuel consumption in typical flight operations. By

There are significant fuel consumption consequences for non-optimal flight operations. This study is intended to analyze and highlight areas of interest that affect fuel consumption in typical flight operations. By gathering information from actual flight operators (pilots, dispatch, performance engineers, and air traffic controllers), real performance issues can be addressed and analyzed. A series of interviews were performed with various individuals in the industry and organizations. The wide range of insight directed this study to focus on FAA regulations, airline policy, the ATC system, weather, and flight planning. The goal is to highlight where operational performance differs from design intent in order to better connect optimization with actual flight operations. After further investigation and consensus from the experienced participants, the FAA regulations do not need any serious attention until newer technologies and capabilities are implemented. The ATC system is severely out of date and is one of the largest limiting factors in current flight operations. Although participants are pessimistic about its timely implementation, the FAA's NextGen program for a future National Airspace System should help improve the efficiency of flight operations. This includes situational awareness, weather monitoring, communication, information management, optimized routing, and cleaner flight profiles like Required Navigation Performance (RNP) and Continuous Descent Approach (CDA). Working off the interview results, trade-studies were performed using an in-house flight profile simulation of a Boeing 737-300, integrating NASA legacy codes EDET and NPSS with a custom written mission performance and point-performance "Skymap" calculator. From these trade-studies, it was found that certain flight conditions affect flight operations more than others. With weather, traffic, and unforeseeable risks, flight planning is still limited by its high level of precaution. From this study, it is recommended that air carriers increase focus on defining policies like load scheduling, CG management, reduction in zero fuel weight, inclusion of performance measurement systems, and adapting to the regulations to best optimize the spirit of the requirement.. As well, air carriers should create a larger drive to implement the FAA's NextGen system and move the industry into the future.

Contributors

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Created

Date Created
  • 2014

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Takeoff Obstacle Clearance Procedures: The Feasibility of Extended Second Segment Climb

Description

To ensure safety is not precluded in the event of an engine failure, the FAA has

established climb gradient minimums enforced through Federal Regulations.

Furthermore, to ensure aircraft do

To ensure safety is not precluded in the event of an engine failure, the FAA has

established climb gradient minimums enforced through Federal Regulations.

Furthermore, to ensure aircraft do not accidentally impact an obstacle on takeoff due to

insufficient climb performance, standard instrument departure procedures have their own

set of climb gradient minimums which are typically more than those set by Federal

Regulation. This inconsistency between climb gradient expectations creates an obstacle

clearance problem: while the aircraft has enough climb gradient in the engine inoperative

condition so that basic flight safety is not precluded, this climb gradient is often not

strong enough to overfly real obstacles; this implies that the pilot must abort the takeoff

flight path and reverse course back to the departure airport to perform an emergency

landing. One solution to this is to reduce the dispatch weight to ensure that the aircraft

retains enough climb performance in the engine inoperative condition, but this comes at

the cost of reduced per-flight profits.

An alternative solution to this problem is the extended second segment (E2S)

climb. Proposed by Bays & Halpin, they found that a C-130H gained additional obstacle

clearance performance through this simple operational change. A thorough investigation

into this technique was performed to see if this technique can be applied to commercial

aviation by using a model A320 and simulating multiple takeoff flight paths in either a

calm or constant wind condition. A comparison of takeoff flight profiles against real

world departure procedures shows that the E2S climb technique offers a clear obstacle

clearance advantage which a scheduled four-segment flight profile cannot provide.

Contributors

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Created

Date Created
  • 2017

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Experimental investigation of typical aircraft field performance versus predicted performance targets

Description

This thesis explores the human factors effects pilots have when controlling the aircraft during the takeoff phase of flight. These variables come into play in the transitory phase from

This thesis explores the human factors effects pilots have when controlling the aircraft during the takeoff phase of flight. These variables come into play in the transitory phase from ground roll to flight, and in the initiation of procedures to abort a takeoff during the ground run. The FAA provides regulations for manufacturers and operators to follow, ensuring safe manufacture of aircraft and pilots that fly without endangering the passengers; however, details regarding accounting of piloting variability are lacking. Creation of a numerical simulation allowed for the controlled variation of isolated piloting procedures in order to evaluate effects on field performance. Reduced rotation rates and delayed reaction times were found to cause significant increases in field length requirements over values published in the AFM. A pilot survey was conducted to evaluate common practices for line pilots in the field, which revealed minimum regulatory compliance is exercised with little to no feedback on runway length requirements. Finally, observation of pilots training in a CRJ-200 FTD gathered extensive information on typical piloting timings in the cockpit. AEO and OEI takeoffs were observed, as well as RTOs. Pilots showed large variability in procedures and timings resulting in significant inconsistency in runway distances used as well as V-speed compliance. The observed effects from pilot timing latency correlated with the numerical simulation increased field length outputs. Variability in piloting procedures results in erratic field performance that deviates from AFM published values that invite disaster in an aircraft operating near its field performance limitations.

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Created

Date Created
  • 2017

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The Doghouse Plot: History, Construction Techniques, and Application

Description

The Doghouse Plot visually represents an aircraft’s performance during combined turn-climb maneuvers. The Doghouse Plot completely describes the turn-climb capability of an aircraft; a single plot demonstrates the relationship between

The Doghouse Plot visually represents an aircraft’s performance during combined turn-climb maneuvers. The Doghouse Plot completely describes the turn-climb capability of an aircraft; a single plot demonstrates the relationship between climb performance, turn rate, turn radius, stall margin, and bank angle. Using NASA legacy codes, Empirical Drag Estimation Technique (EDET) and Numerical Propulsion System Simulation (NPSS), it is possible to reverse engineer sufficient basis data for commercial and military aircraft to construct Doghouse Plots. Engineers and operators can then use these to assess their aircraft’s full performance envelope. The insight gained from these plots can broaden the understanding of an aircraft’s performance and, in turn, broaden the operational scope of some aircraft that would otherwise be limited by the simplifications found in their Airplane Flight Manuals (AFM). More importantly, these plots can build on the current standards of obstacle avoidance and expose risks in operation.

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Created

Date Created
  • 2017

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Detailed Design of a Pulsed Plasma Thrust Stand

Description

This thesis gives a detailed design process for a pulsed type thruster. The thrust stand designed in this paper is for a Pulsed Plasma Thruster built by Sun Devil Satellite

This thesis gives a detailed design process for a pulsed type thruster. The thrust stand designed in this paper is for a Pulsed Plasma Thruster built by Sun Devil Satellite Laboratory, a student organization at Arizona State University. The thrust stand uses a torsional beam rotating to record displacement. This information, along with impulse-momentum theorem is applied to find the impulse bit of the thruster, which varies largely from other designs which focus on using the natural dynamics their fixtures. The target impulse to record on this fixture was estimated to be 275 μN-s of impulse. Through calibration and experimentation, the fixture is capable of recording an impulse of 332 μN-s ± 14.81 μN-s, close to the target impulse. The error due to noise was characterized and evaluated to be under 5% which is deemed to be acceptable.

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Created

Date Created
  • 2017

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Propellant Mass Scaling and Decoupling and Improved Plasma Coupling in a Pulsed Inductive Thruster

Description

Two methods of improving the life and efficiency of the Pulsed Inductive Thruster

(PIT) have been investigated. The first is a trade study of available switches to

determine the best device to

Two methods of improving the life and efficiency of the Pulsed Inductive Thruster

(PIT) have been investigated. The first is a trade study of available switches to

determine the best device to implement in the PIT design. The second is the design

of a coil to improve coupling between the accelerator coil and the plasma. Experiments

were done with both permanent and electromagnets to investigate the feasibility of

implementing a modified Halbach array within the PIT to promote better plasma

coupling and decrease the unused space within the thruster. This array proved to

promote more complete coupling on the edges of the coil where it had been weak in

previous studies. Numerical analysis was done to predict the performance of a PIT

that utilized each suggested switch type. This model utilized the Alfven velocity to

determine the critical mass and energy of these theoretical thrusters.

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Created

Date Created
  • 2018

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Early Wing Structural Design for Stiffness and Frequency Response

Description

This paper describes an effort to bring wing structural stiffness and aeroelastic considerations early in the conceptual design process with an automated tool. Stiffness and aeroelasticity can be well represented

This paper describes an effort to bring wing structural stiffness and aeroelastic considerations early in the conceptual design process with an automated tool. Stiffness and aeroelasticity can be well represented with a stochastic model during conceptual design because of the high level of uncertainty and variability in wing non-structural mass such as fuel loading and control surfaces. To accomplish this, an improvement is made to existing design tools utilizing rule based automated design to generate wing torque box geometry from a specific wing outer mold-line. Simple analysis on deflection and inferred stiffness shows how early conceptual design choices can strongly impact the stiffness of the structure. The impacts of design choices and how the buckling constraints drive structural weight in particular examples are discussed. The model is then carried further to include a finite element model (FEM) to analyze resulting mode shapes and frequencies for use in aeroelastic analysis. The natural frequencies of several selected wing torque boxes across a range of loading cases are compared.

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Created

Date Created
  • 2018

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Transonic flow around swept wings: revisiting Von Kármáns similarity rule

Description

Modern aircraft are expected to fly faster and more efficiently than their predecessors. To improve aerodynamic efficiency, designers must carefully consider and handle shock wave formation. Presently, many designers utilize

Modern aircraft are expected to fly faster and more efficiently than their predecessors. To improve aerodynamic efficiency, designers must carefully consider and handle shock wave formation. Presently, many designers utilize computationally heavy optimization methods to design wings. While these methods may work, they do not provide insight. This thesis aims to better understand fundamental methods that govern wing design. In order to further understand the flow in the transonic regime, this work revisits the Transonic Similarity Rule. This rule postulates an equivalent incompressible geometry to any high speed geometry in flight and postulates a “stretching” analogy. This thesis utilizes panel methods and Computational Fluid Dynamics (CFD) to show that the “stretching” analogy is incorrect, but instead the flow is transformed by a nonlinear “scaling” of the flow velocity. This work also presents data to show the discrepancies between many famous authors in deriving the accurate Critical Pressure Coefficient (Cp*) equation for both swept and unswept wing sections. The final work of the thesis aims to identify the correct predictive methods for the Critical Pressure Coefficient.

Contributors

Agent

Created

Date Created
  • 2016