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Manual Manipulation of Engine Throttles for Emergency Flight Control
02 Aug 2013-
TL;DR: In this paper, a history of accidents or incidents in which some or all flight controls were lost, manual TOC results for a wide range of airplanes from simulation and flight, and suggested techniques for flying with throttles only and making a survivable landing.
Abstract: If normal aircraft flight controls are lost, emergency flight control may be attempted using only engines thrust. Collective thrust is used to control flightpath, and differential thrust is used to control bank angle. Flight test and simulation results on many airplanes have shown that pilot manipulation of throttles is usually adequate to maintain up-and-away flight, but is most often not capable of providing safe landings. There are techniques that will improve control and increase the chances of a survivable landing. This paper reviews the principles of throttles-only control (TOC), a history of accidents or incidents in which some or all flight controls were lost, manual TOC results for a wide range of airplanes from simulation and flight, and suggested techniques for flying with throttles only and making a survivable landing.
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21 Aug 2006
TL;DR: In this article, the authors present a description of a large transp ort aircraft simulation benchmark that includes a suitable set of assessment criteria for the integrated evaluation of fault tolerant flight control systems (FTFC).
Abstract: This paper presents a description of a large transp ort aircraft simulation benchmark that includes a suitable set of assessment criteria , for the integrated evaluation of fault tolerant flight control systems (FTFC). These syste ms consist of a combination of novel fault detection, isolation (FDI) and reconfigurable contr ol schemes. In 2004, a research group on Fault Tolerant Control, comprising a collaboration of nine European partners from industry, universities and research institutions, w as established within the framework of the Group for Aeronautical Research and Technology in Europe (GARTEUR) co-operation program. The aim of the research group, Flight Mechanics Action Group FM-AG(16), is to demonstrate the capability and viability of modern FTFC schemes when applied to a realistic, nonlinear design problem and to assess t heir capability to improve aircraft survivability. The test scenarios that are an integ ral part of the benchmark were selected to provide challenging assessment criteria to evaluate the effectiveness and potential of the FTFC methods being investigated. The application of fault reconstruction and modelling techniques based on (accident) flight data, as desc ribed in this paper, has resulted in high fidelity non-linear aircraft and fault models for t he design and evaluation of modern FTFC methods.
68 citations
TL;DR: A thorough comparison of several different aspects is conducted to understand the advantage and disadvantages of various FTC techniques to motivate researchers to further developing FTC and FDI approaches.
Abstract: Faults and failures in the system components are two main reasons for the instability and the degradation in control performance. In recent decades, fault-tolerant control (FTC) approaches have been introduced to improve the resiliency of control systems against faults and failures. In general, FTC techniques are classified into active and passive approaches. This paper reviews fault and failure causes in control systems and discusses the latest solutions that are introduced to make the control system resilient.The recent achievements in fault detection and isolation (FDI) approaches and active FTC designs are investigated. Furthermore, a thorough comparison of several different aspects is conducted to understand the advantage and disadvantages of various FTC techniques to motivate researchers to further developing FTC and FDI approaches.
63 citations
Cites background from "Manual Manipulation of Engine Throt..."
...This kind of failure has been reported as the main reason for several aircraft crashes such as Flight 85 (B-747, Alaska, 2002) [30] (where the lower rudder runaway led to full left deflection and caused the excessive roll of the aircraft)....
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...This type of failure led to flight incidents such as Flight 1080 (Lockheed L-1011, San Diego, 1977) [30], and flight 96 (DC-10, Ontario, 1972) [30]....
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01 Nov 2009
TL;DR: In this paper, a sensitivity analysis revealed a complex interaction of the limits and the difficulty in predicting the way to achieve the fastest response, and demonstrated that significantly faster engine response can be achieved compared to standard Bill of Material control.
Abstract: Damaged aircraft have occasionally had to rely solely on thrust to maneuver as a consequence of losing hydraulic power needed to operate flight control surfaces. The lack of successful landings in these cases inspired research into more effective methods of utilizing propulsion-only control. That research demonstrated that one of the major contributors to the difficulty in landing is the slow response of the engines as compared to using traditional flight control. To address this, research is being conducted into ways of making the engine more responsive under emergency conditions. This can be achieved by relaxing controller limits, adjusting schedules, and/or redesigning the regulators to increase bandwidth. Any of these methods can enable faster response at the potential expense of engine life and increased likelihood of stall. However, an example sensitivity analysis revealed a complex interaction of the limits and the difficulty in predicting the way to achieve the fastest response. The sensitivity analysis was performed on a realistic engine model, and demonstrated that significantly faster engine response can be achieved compared to standard Bill of Material control. However, the example indicates the need for an intelligent approach to controller limit adjustment in order for the potential to be fulfilled.
47 citations
01 Jan 2011
TL;DR: This chapter formally provides a definition of the terms fault and failure and briefly discusses the different types of faults and failures which can occur in actuators and sensors—with specific aircraft examples.
Abstract: This chapter formally provides a definition of the terms fault and failure and briefly discusses the different types of faults and failures which can occur in actuators and sensors—with specific aircraft examples. The chapter introduces the concept of fault tolerant control and gives a general overview of the different FTC and FDI research fields. The main concepts and strategies behind some of the FTC and FDI schemes in the literature are also discussed.
40 citations
11 Jun 2012
TL;DR: In this article, a modification to the existing Min-Max control selection structure is proposed, referred to as a Conditionally Active (CA) limit regulator, which allows the engine to exceed any safety or operational limits during transients due to throttle commands.
Abstract: Current aircraft engine control logic uses a Min-Max control selection structure to prevent the engine from exceeding any safety or operational limits during transients due to throttle commands. This structure is inherently conservative and produces transient responses that are slower than necessary. In order to utilize the existing safety margins more effectively, a modification to this architecture is proposed, referred to as a Conditionally Active (CA) limit regulator. This concept uses the existing Min-Max architecture with the modification that limit regulators are active only when the operating point is close to a particular limit. This paper explores the use of CA limit regulators using a publicly available commercial aircraft engine simulation. The improvement in thrust response while maintaining all necessary safety limits is demonstrated in a number of cases.
37 citations
Cites background from "Manual Manipulation of Engine Throt..."
...The output, y1, is initially below the limit and both Equations (1) and (2) are false....
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...Conditions 1 and 2 can be developed into equations analogous to Equations (1) and (2) with non-negative design parameters α2 and β2. min222 *)1( yy α+≤ (3) min2222 ** yTydt dy ≤∆β+ (4) It is worth noting that when Condition 1 is met (the variable is “close” to the limit) that the construction of Condition 2 can tB....
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...The switches shown on the output of each limit regulator only connect to the Max and Min selector blocks when both bounding conditions are true—Equations (5) and (6) for the Max limit regulator and Equations (7) and (8) for the Min limit regulator....
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...To determine the effectiveness of the conditionally active limit regulators on the engine response, three situations are evaluated: (1) a case where a transient limit regulator is necessary to ensure safe operation, (2) a case where a steadystate limit regulator is necessary to ensure safe operation, and (3) a case where a limit regulator becomes active unnecessarily during a transient....
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...The discrete version of the maximum limit inequalities Equations (5) and (6) is listed below where e[k] refers to the error at the current time index and e[k-1] to the error at the previous time step. max11 *][ yke α≤ (9) ( ) T kekeke T ∆β − ≤−− ∆ * ][]1[][1 1 1 11 (10) Also, the designer may find it desirable to use a filtered version of e[k] to reduce noise....
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References
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TL;DR: In contrast, the authors argue that there are many everyday contexts in which we hold agents responsible for their acts even though considerations unrelated to determinism strongly suggest that they cannot help performing them.
Abstract: Incompatibilists affirm, while compatibilists deny, that the truth of determinism would mean that we lack control over, and so are not responsible for, any of our actions. Though defined as opposites, compatibilism and incompatibilism both treat determinism as the main threat to our having enough control over our actions to be morally responsible for them. Here, by contrast, I want to call attention to another, less exotic threat to our having that much control. There are, I will argue, many everyday contexts in which we hold agents responsible for their acts even though considerations unrelated to determinism strongly suggest that they cannot help performing them. These contexts may not prevent us from specifying a conception of control that preserves our standard judgments of responsibility, but they do make that task even more difficult than is generally appreciated.
190 citations
01 Sep 1996
TL;DR: Results from a 36-flight evaluation showed that the PCA system can be used to safety land an airplane that has suffered a major flight control system failure and was used to recover from a severe upset condition, descend, and land.
Abstract: A propulsion-controlled aircraft (PCA) system for emergency flight control of aircraft with no flight controls was developed and flight tested on an F-15 aircraft at the NASA Dryden Flight Research Center. The airplane has been flown in a throttles-only manual mode and with an augmented system called PCA in which pilot thumbwheel commands and aircraft feedback parameters were used to drive the throttles. Results from a 36-flight evaluation showed that the PCA system can be used to safety land an airplane that has suffered a major flight control system failure. The PCA system was used to recover from a severe upset condition, descend, and land. Guest pilots have also evaluated the PCA system. This paper describes the principles of throttles-only flight control; a history of loss-of-control accidents; a description of the F-15 aircraft; the PCA system operation, simulation, and flight testing; and the pilot comments.
49 citations
01 Jun 1991
TL;DR: The use of throttle control laws to provide adequate flying qualities for flight path control in the event of a total loss of conventional flight control surface use was evaluated in this paper, where the results were based on a simulation evaluation by transport research pilots of a B-720 transport with visual display.
Abstract: The use of throttle control laws to provide adequate flying qualities for flight path control in the event of a total loss of conventional flight control surface use was evaluated. The results are based on a simulation evaluation by transport research pilots of a B-720 transport with visual display. Throttle augmentation control laws can provide flight path control capable of landing a transport-type aircraft with up to moderate levels of turbulence. The throttle augmentation mode dramatically improves the pilots' ability to control flight path for the approach and landing flight condition using only throttle modulation. For light turbulence, the average Cooper-Harper pilot rating improved from unacceptable to acceptable (a pilot rating improvement of 4.5) in going from manual to augmented control. The low frequency response characteristics of the engines require a considerably different piloting technique. The various techniques used by the pilot resulted in considerable scatter in data. Many pilots readily adapted to a good piloting technique while some had difficulty. A new viable approach is shown to provide independent means of redundancy of transport aircraft flight path control.
45 citations
01 Oct 1997
TL;DR: An emergency flight control system that uses only engine thrust, called the propulsion-controlled aircraft (PCA) system, was developed and flight tested on an MD-11 airplane as discussed by the authors.
Abstract: An emergency flight control system that uses only engine thrust, called the propulsion-controlled aircraft (PCA) system, was developed and flight tested on an MD-11 airplane. The PCA system is a thrust-only control system, which augments pilot flightpath and track commands with aircraft feedback parameters to control engine thrust. The PCA system was implemented on the MD-11 airplane using only software modifications to existing computers. Results of a 25-hr flight test show that the PCA system can be used to fly to an airport and safely land a transport airplane with an inoperative flight control system. In up-and-away operation, the PCA system served as an acceptable autopilot capable of extended flight over a range of speeds, altitudes, and configurations. PCA approaches, go-arounds, and three landings without the use of any normal flight controls were demonstrated, including ILS-coupled hands-off landings. PCA operation was used to recover from an upset condition. The PCA system was also tested at altitude with all three hydraulic systems turned off. This paper reviews the principles of throttles-only flight control, a history of accidents or incidents in which some or all flight controls were lost, the MD-11 airplane and its systems, PCA system development, operation, flight testing, and pilot comments.
39 citations