Browse Topic: Air data computers

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Guidelines for the Integration of Electronic Engine Control Systems for Transport Category (Part 25) and General Aviation (Part 23) AircraftAIR5924B (Current)11/26/2025
This SAE Aerospace Information Report (AIR) provides methodologies and approaches that have been used to install and integrate full-authority-digital-engine-control (FADEC) systems on transport category aircraft. Although most of the information provided is based on turbofan engines installed on large commercial transports, many of the issues raised are equally applicable to corporate, general aviation, regional and commuter aircraft, and to military installations, particularly when commercial aircraft are employed by military users. The word “engine” is used to designate the aircraft propulsion system. The engine station designations used in this report are shown in Figure 1. Most of the material concerns an Electronic Engine Control (EEC) with its associated software, and its functional integration with the aircraft. However, the report also addresses the physical environment associated with the EEC and its associated wiring and sensors. Since most of today’s transport category engines use dual-channel full-authority digital engine control (FADEC) systems, this is the configuration which is addressed. A typical FADEC system configuration is shown in Figure 2.
E-36 Electronic Engine Controls Committee
Static System Error Compensation in Air Data Calibration for Tiltrotor System CertificationF-0081-2025-01285/20/2025
Air data measurement and calibration are fundamental components in the pursuit of accurate and reliable aerodynamic assessments. The systematic collection of essential data regarding air properties are important for evaluating aircraft performance under various conditions and configurations. The scope is to achieve a comprehensive understanding of airflow characteristics, which is fundamental for design improvements and operational strategies, contributing to safer and more efficient flight operations in a several range of scenarios. This type of data measurement is even more challenging for the AW609 Tiltrotor which combines vertical take-off technology capabilities with the fixed-wing flight efficiency. The activity starts from known pitot-static system calibration methodologies for conventional applications and shows what were the difficulties encountered in a non-conventional Tiltrotor approach. The paper goes through the presentation of the original Pitot-Static and Air Data system and all the problematics that driven to a design change. After the presentation of the new architecture and the new data collection activity, it will be discussed the optimization of the data calibration strategy, also related to some peculiarities of the Tiltrotor, and how it drives to infer the calibration curves for the Air Data Computers (ADCs).
Evangelista, Marco, Mori, Massimiliano
IAQG-03282025-1 IAQG-03282025-1 (Current)4/2/2025
IAQG-03282025-1
IAQG-1 Standards Committee
Flight Test Procedures for Static Pressure Systems Installed in Subsonic Transport AircraftARP921B (Current)12/22/2020
This SAE Aerospace Recommended Practice (ARP) covers the test procedures and equipment for performing flight testing on pitot-static systems installed in subsonic transport type aircraft.
A-4 Aircraft Instruments Committee
DATALINK GROUND SYSTEMS STANDARD AND INTERFACE SPECIFICATION (DGSS/IS)ARINC620-10 (Current)7/31/2020
ARINC Specification 620 defines the interfaces between the Datalink Service Provider (DSP) and the aircraft, other ground-based datalink services, and users. The datalink ground system standard definition supports traditional ACARS and AOA protocols, as well as Media Independent Aircraft Messaging (MIAM) as defined by ARINC Specification 841. MIAM messages can be much larger than ACARS messages (5 MB versus 3.3 kB per message). Supplement 10 improves Controller-Pilot Data Link Communications (CPDLC) by defining a “Deliver By (DB)” period that allows the DSP, that originated the message, to intercept and discard the message if it is not delivered by the specified time. Supplement 10 also adds a Media Advisory code for ACARS over IP (AoIP) indicating that an ACARS non Safety Services messages is being transferred over IP links. New Reason Codes are assigned for un-transmittable or undeliverable messages. ACARS Character set clarifications are also provided in Supplement 10.
Airlines Electronic Engineering Committee
Air Data Computer – Minimum Performance StandardAS8002B (Current)4/28/2020
This SAE Aerospace Standard (AS) covers air data computer equipment (hereinafter designated the computer) which when connected to sources of aircraft electrical power, static pressure, total pressure, outside air temperature, and others specified by the manufacturer (singly or in combination) provides some or all of the following computed air data output signals (in analog and/or digital form) which may supply primary and/or standby flight instruments: Pressure Altitude Pressure Altitude, Baro-Corrected Vertical Speed Calibrated Airspeed Mach Number Maximum Allowable Airspeed Over-speed Warning Total Air Temperature
A-4 Air Data Subcommittee
Barometry for Altimeter CalibrationAIR1075B (Current)2/20/2020
This SAE Aerospace Information Report (AIR) is concerned only with aspects directly relating to available accuracy. While well-designed photoelectric, inductive or capacitive readers and pressure regulators, and other accessories are highly desirable for convenience and production rate, they are considered to be outside the scope of this AIR.
A-4 Aircraft Instruments Committee
Analysis and Automated Detection of Ice Crystal Icing Conditions Using Geostationary Satellite Datasets and In Situ Ice Water Content Measurements2019-01-19536/10/2019
Recent studies have found that high mass concentrations of ice particles in regions of deep convective storms can adversely impact aircraft engine and air probe (e.g. pitot tube and air temperature) performance. Radar reflectivity in these regions suggests that they are safe for aircraft penetration, yet high ice water content (HIWC) is still encountered. The aviation weather community seeks additional remote sensing methods for delineating where ice particle (or crystal) icing conditions are likely to occur, including products derived from geostationary (GEO) satellite imagery that is now available in near-real time at increasingly high spatio-temporal detail from the global GEO satellite constellation. A recent study using a large sample of co-located GEO satellite and in-situ isokinetic evaporator probe (IKP-2) total water content (TWC) datasets found that optically thick clouds with tops near to or above the tropopause in close proximity (≤ 40 km) to convective updrafts were most likely to contain high TWC (TWC ≥ 1 g m-3). These parameters are detected using automated algorithms and combined to generate a HIWC probability (PHIWC) product at the NASA Langley Research Center (LaRC). Seven NASA DC-8 aircraft flights were conducted in August 2018 over the Gulf of Mexico and the tropical Pacific Ocean during the HIWC Radar II field campaign. The convection sampled during four flights was observed by GOES-16 at 1- or 5-minute intervals, providing the first opportunity to analyze product performance from this new satellite. This paper will (1) present initial comparisons between GOES-16 and IKP-2 datasets during HIWC Radar II, (2) demonstrate GOES-16 products for select periods when high TWC was encountered with an emphasis on three flights with 1-minute imagery, (3) compare GOES observations and derived products from the HIWC Radar I and II campaigns.
Bedka, Kristopher, Yost, Christopher, Nguyen, Louis, Strapp, J. Walter, Ratvasky, Thomas, Khlopenkov, Konstantin, Scarino, Benjamin, Bhatt, Rajendra, Spangenberg, Douglas, Palikonda, Rabindra
A Research on the Icing Flight Test and Computational Simulation for the Design of Ice Protection System for KUH (Korean Utility Helicopter)F-0075-2019-147385/13/2019
Icing of the fuselage and blades may occur when the helicopter is flying in the icing area. If ice accretion occurs in the ADS(Air Data System) of the fuselage, normal speed and altitude information are lost, making it difficult to flight. When windshield icing occurs, the view of pilot is limited and flight is difficult. Also, the ice accretion of the blades deforms the outer shape of the blades (Ref. 1) and makes the dynamic characteristics unstable due to an abnormal weight increase, resulting in deterioration of performance, deterioration of maneuverability, and structural instability. To avoid this, an anti-icing or de-icing system is required. Therefore, if the aircraft is not fitted with a proper anti-icing system, it is not possible to operate under icing conditions. However, it is difficult to design a proper anti-icing system considering the position of anti-icing protection area and icing phenomenon due to limitation of electric power, weight, thermal damage temperature limit, shape and so on. It is essential of understanding of anti-icing mechanism for selection and design of appropriate anti-ice system considering configuration (impingement limit, collection efficiency), material (thermal fatigue limit, heating source) and icing amount (collection efficiency, stagnation point). This paper introduces the preparation procedure (analysis and simulation, design, scaled model test) of icing certification test and the artificial/natural icing flight test method for proving helicopter icing through KUH case, and describes the characteristics of each system for the de/anti-icing system design of the helicopter, the computational analysis method, comparison with the test result, and the improvement method of the de/anti-icing system.
Park, Nameun, Kim, Jik, Lee, Sang, Woo, Cheol, Kim, Hyung, Hwang, Yoo
Guidelines for Time-Limited-Dispatch (TLD) Analysis for Electronic Engine Control SystemsARP5107C (Current)9/4/2018
This SAE Aerospace Recommended Practice (ARP) provides methodologies and approaches which have been used for conducting and documenting the analyses associated with the application of Time Limited Dispatch (TLD) to the thrust control reliability of Full Authority Digital Engine Control (FADEC) systems. The TLD concept is one wherein a fault-tolerant system is allowed to operate for a predetermined length of time with faults present in the redundant elements of the system, before repairs are required. This document includes the background of the development of TLD, the structure of TLD that was developed and implemented on present generation commercial transports, and the analysis methods used to validate the application of TLD on present day FADEC equipped aircraft. Although this document is specific to TLD analyses (for FADEC systems) of the loss of thrust control, the techniques and processes discussed in this document are considered applicable to other FADEC system failure effects or other systems, such as: thrust reverser, and propeller control systems, and overspeed protection systems.
E-36 Electronic Engine Controls Committee
New Products & Services: December 2017 Aerospace Manufacturing & FabricationTBMG-2793912/1/2017
Airborne Elastic Backscatter and Raman Polychromator for Ash DetectionTBMG-261921/1/2017
Volcanic ash is a significant hazard to aircraft engines and electronics. It has caused damage to unwary aircraft and disrupted air travel for thousands of travelers, costing millions of dollars. The small, jagged fragments of rocks, minerals, and volcanic glass that constitute volcanic ash are about the size of sand and silt. Volcanic ash is hard, does not dissolve in water, is extremely abrasive and corrosive, and conducts electricity when wet. The upper winds transport the particles away to eventual dispersal in an ash cloud. Ash clouds typically form above 20,000 feet, but the lower limit of the initial cloud depends on both the height of the volcanic vent and the vigor with which material is ejected from it.
Aircraft Flight Control Systems DescriptionsAIR4094A (Current)7/18/2016
This SAE Aerospace Information Report (AIR) supplies information on the flight control systems incorporated on various current and historic fixed wing, rotary wing, and tilt rotor aircraft. A brief description of the aircraft is followed by a description of the flight control system, some specific components, drawings of the internal arrangement, block diagrams, and schematics. System operation redundancy management is also presented.
A-6A3 Flight Control and Vehicle Management Systems Cmt
Airborne Elastic Backscatter and Raman Polychromator for Ash DetectionTBMG-248466/1/2016
Volcanic ash is a significant hazard to aircraft engine and electronics. It has caused damage to unwary aircraft and disrupted air travel for thousands of travelers, costing millions of dollars. The small, jagged fragments of rocks, minerals, and volcanic glass that constitute volcanic ash are about the size of sand and silt. Volcanic ash is hard, does not dissolve in water, is extremely abrasive and corrosive, and conducts electricity when wet. The upper winds transport the particles away to eventual dispersal in an ash cloud. Ash clouds typically form above 20,000 feet, but the lower limit of the initial cloud depends on both the height of the volcanic vent and the vigor with which material is ejected from it.
Pressure Altimeter SystemsAS8009C (Current)5/24/2016
This SAE Aerospace Standard (AS) specifies minimum performance requirements for pressure altimeter systems other than air data computers. This document covers altimeter systems that measure and display altitude as a function of atmospheric pressure. The pressure transducer may be contained within the instrument display case or located remotely. Requirements for air data computers are specified in AS8002. Some requirements for nontransducing servoed altitude indicators are included in AS791. This document does not address RVSM requirements because general RVSM requirements cannot be independently detailed at the component level. The instrument system specified herein does not include aircraft pressure lines. Unless otherwise specified, whenever the term “instrument” is used, it is to be understood to be the complete system of pressure transducer components, any auxiliary equipment, and display components. The test procedures specified herein apply specifically to mechanical type instruments. Solid state instruments or automatic test instrumentation may require other test procedures. Such differing procedures shall be justified prior to use.
A-4 Air Data Subcommittee
Descriptions of Systems Integration Test Rigs (Iron Birds) For Aerospace ApplicationsAIR5992 (Current)10/16/2015
This Aerospace Information Report (AIR) provides information on systems integration rigs, commonly referred to as “Iron Birds” for aerospace applications. a It includes background historical information including descriptions of Iron Birds produced to date, important component elements and selection rationale, hydraulic system design and operational modes and illustrates the design approaches to be considered. b It provides illustrations of the various systems that should be considered for Iron Bird testing in the development phase and utilization during the production program. c It includes recommendations for simulation, component development tests, system integration and lessons learned.
A-6A3 Flight Control and Vehicle Management Systems Cmt
FMS and AFCS Interface for 4D Trajectory Operations2015-01-24589/15/2015
The future revolution of the air traffic system imposes the development of a new class of Flight Management Systems (FMS), capable of providing the aircraft with real-time reference flight parameters, necessary to fly the aircraft through a predefined sequence of waypoints, while minimizing fuel consumption, noise and pollution emissions. The main goal is to guarantee safety operations while reducing the aircraft environmental impact, according to the main international research programs. This policy is expected to affect also the Unmanned Aerial Systems (UASs), as soon as they will be allowed to fly beyond the restricted portions of the aerospace where they are currently confined. In the future, in fact, UASs are expected to fly within the whole civilian airspace, under the same requirements deriving from the adoption of the Performance Based Navigation (PBN). For UASs, the most attractive strategy to reach this goal consists in adopting the mature technology developed for the civil aviation both in terms of operative functions and performance. The current literature lacks of examples dedicated to the control algorithms, which should operate the onboard autopilots and guide the aircraft through the reference calculated trajectory. This paper presents the implementation of a new generation FMS, composed by a trajectory optimization tool and a guidance and control algorithm, interfaced with a suite of proprietary Automatic Flight Control Systems (AFCSs). Different guidance and control algorithms for the FMS are presented and tested on a 6DOF nonlinear mathematical model of a civil aircraft (MASLab), developed within the Clean Sky research program.
Sirigu, Giuseppe, Battipede, Manuela, Gili, Piero, Cassaro, Mario
Minimum Performance Standard for Pitot and Pitot-Static ProbesAS8006A (Current)8/8/2015
This SAE Aerospace Standard (AS) covers the following basic types: Type I - Pitot pressure, straight and L-shaped, electrically heated. Type II - Pitot and static pressures, straight and L-shaped, electrically heated.
A-4 Air Data Subcommittee
Wireless Sensing - Future's Password to Digital Avionics System2014-01-21329/16/2014
Performance of Avionics systems is dictated by the timely availability and usage of critical health parameters. Various sensors are extensively used to acquire and communicate the desired parameters. In today's scenario, sensors are hardwired. The number of sensors is growing due to automation which increases the accuracy of intended Aircraft functions. Sensors are distributed all over the Aircraft and they are connected through wired network for signal processing and communication. LRUs (Line Replaceable Unit) which are integrating various sensors also use a wired approach for communication. The use of a wired network approach poses challenges in terms of cable routing, stray capacitances, noise, mechanical structure and added weight to the structure. The weight of cables contributes significantly to the overall weight of the aircraft. As the weight of Aircraft increases, the required fuel quantity also increases. The Key driver for Airline operational cost is fuel. Fuel quantity is a direct function of weight. Use of wireless sensors in aircraft brings in tremendous advantages in terms of design optimization, flexibility in sensor configuration and weight optimization. Even though the avionics industry is trying to adopt wireless sensors, there are some points of concern in deploying wireless sensors and networks across the aircraft. This paper describes the comparative performance of wired and wireless sensors, type of wireless sensors & interfaces, frequency performance, protocols, network topologies and qualification standards. This paper also discusses the constraints and challenges in deploying wireless sensor network across the aircraft.
Vadgaonkar, Prashant, Janardhan, Ullas, Sivaramasastry, Adishesha
Embedded COTS - A Gateway for New Processors/High Performing Machines to Digital Avionics System Industry2014-01-22069/16/2014
Today's digital avionics systems leverage the use of the Embedded COTS (Commercial Off The Shelf) hardware to fit the need of small form factor, low power, reduced time to market and reduced development time with efficient use of DO-254 for compliance of product. COTS modules are entering in digital avionics systems such as COM (Computer On Module)/SOM (System On Module)/SIP (System In Package) with huge advancement in semiconductor and packaging industry. In today's scenario COTS are very useful for DAL (Development Assurance Level) C and below as the efforts on compliance for DAL A and B are huge. This paper proposes to use these for DAL A and B as well, where one can get enormous benefit on efforts of compliance and time to market. This paper makes an attempt to explain the current scenario of the Embedded COTS usage in Avionics Systems. This paper also brings the study of the selection process of Embedded COTS along with the important selection parameters, constraints, challenges and guidelines. This paper also makes an attempt to visualize next generation of COTS along with its advantages and disadvantages. This paper finally brings out probable thoughts and outcome of study of embedded COTS which can be leveraged for using embedded COTS in various Avionics Systems.
Vadgaonkar, Prashant
Guide to Temperature Monitoring in Aircraft Gas Turbine EnginesAIR1900A (Current)5/1/2014
This SAE Aerospace Information Report (AIR) provides an overview of temperature measurement for engine monitoring systems in various areas of aircraft gas turbine engines while focusing on current usage and methods, systems, selection criteria, and types of hardware. This document emphasizes temperature monitoring for diagnostics and condition monitoring purposes.
E-32 Aerospace Propulsion Systems Health Management
Air-Data System Detects Aircraft IcingTBMG-1878512/1/2013
Michigan Aerospace Corporation (MAC) has begun work on a Phase I Small Business Innovation Research (SBIR) contract with NASA’s Langley Research Center. The contract, “RIDES: Raman Icing Detection System,” extends MAC’s present aircraft-based optical airdata system technology — which uses ultraviolet laser light to measure air speed, direction, temperature, and density — to also detect conditions aloft when ice is likely to form, enabling a multi-hazard sensing capability.
Small Airplane Considerations for the Guidelines for Development of Civil Aircraft and Systems2013-01-22339/17/2013
On September 30, 2011, certification authorities released Advisory Circular 20-174[1], Development of Civil Aircraft and Systems, which recognizes the Society of Automotive Engineers (SAE) Aerospace Recommended Practice (ARP) 4754A and the European equivalent ED-79A [2], in order to address “the concern of possible development errors due to the ever increasing complexity of modern aircraft and systems.” ARP4754A/ED-79A describes a process of development assurance which helps reduce the risk of design errors in the development of aircraft systems. This process is necessary for complex systems not easily comprehended by deterministic analyses or tests. This ARP was developed “in the context of Title 14 of the Code of Federal Regulations (14 CFR) part 25,” a category which includes complex systems such as full fly-by-wire flight controls. However, this paper shows that such systems are the exception to most, recent civil airplane designs. Of new airplanes designed in the last 10 years, most implement systems which are simple and easily comprehended. Many of these simpler aircraft are in the part 23 category, which the AC also associates to this ARP. This paper shows that the ARP, as written, does not consider simple systems and may unnecessarily burden the development of such systems through this lack of recognition. This paper reviews the current diversity of system complexity, discusses the regulatory and technical drivers for this diversity, and provides recommendations for incorporating such considerations in the ARP while preserving its original intent.
Voros, Robert E.
Multi-Axis Serially Redundant, Single Channel, Multi-Path FBW Flight Control System2013-01-22579/17/2013
A multi-axis serially redundant, single channel, multi-path FBW (FBW) control system comprising: serially redundant flight control computers in a single channel where only one “primary” flight control computer is active and controlling at any given time; a matrix of parallel flight control surface controllers including stabilizer motor control units (SMCU) and actuator electronics control modules (AECM) define multiple control paths within the single channel, each implemented with dissimilar hardware and which each control the movement of a distributed set of flight control surfaces on the aircraft in response to flight control surface commands from the primary flight control computer, and a set of (pilot and co-pilot) controls and aircraft surface/reference/navigation sensors and systems which provide input to a primary flight control computer and are used to generate the flight control surface commands in accordance with the control law algorithms implemented in the flight control computers.
Lin, Shu, Smith, Tim, De Serres, Pierre
Guidelines for the Integration of Electronic Engine Control Systems for Transport Category (Part 25) and General Aviation (Part 23) AircraftAIR5924A (Historical)1/16/2013
This SAE Aerospace Information Report (AIR) provides methodologies and approaches that have been used to install and integrate full-authority-digital-engine-control (FADEC) systems on transport category aircraft. Although most of the information provided is based on turbofan engines installed on large commercial transports, many of the issues raised are equally applicable to corporate, general aviation, regional and commuter aircraft, and to military installations, particularly when commercial aircraft are employed by military users. The word “engine” is used to designate the aircraft propulsion system. The engine station designations used in this report are shown in Figure 1. Most of the material concerns an Electronic Engine Control (EEC) with its associated software, and its functional integration with the aircraft. However, the report also addresses the physical environment associated with the EEC and its associated wiring and sensors. Since most of today’s transport category engines use dual-channel full-authority digital engine control (FADEC) systems, this is the configuration which is addressed. A typical FADEC system configuration is shown in Figure 2.
E-36 Electronic Engine Controls Committee
SOFIA Closed- and Open-Door Aerodynamic AnalysesTBMG-126471/1/2012
Work to evaluate the aerodynamic characteristics and the cavity acoustic environment of the SOFIA (Stratospheric Observatory for Infrared Astronomy) airplane has been completed. The airplane has been evaluated in its closed-door configuration, as well as several open-door configurations (see figure). Work performed included: acoustic analysis tool development, cavity acoustic evaluation, stability and control parameter estimation, air data calibration, and external flow evaluation.
Holistic Granular Programming: A Novel Approach for Modeling Aircraft2011-01-276410/18/2011
Description of work-in-progress design candidates during the pre-concept and conceptual aircraft design stages have traditionally followed protocol compatible with the later, more mature phases of contemporary product development, i.e. preliminary and detailed design. Up to this moment in time there has been a natural, intuitive tendency to approach design description using geometry as the initial basis upon which all analysis and design refinement could proceed. Design and integration, whether kinematic or structural (static) systems, and irrespective of applications, should be treated as a holistic problem with functionality as opposed to geometric description of a physically tangible artifact being the first step in product definition. This paper presents a coherent, logical method of describing an aircraft concept using functionality as a basis. Hereafter known as Holistic Granular Programming (HGP), any collection of assemblies and components can be described mathematically, and, subsequently analyzed as an engineering safety system. Thereafter, a discussion is given detailing how HGP can be integrated within the Conceptual Design Tool (CDT), an open-source, multi-disciplinary framework for aircraft design currently being developed at Bauhaus Luftfahrt. Independent of any particular tool implementation a number of other questions are addressed, such as: how to map the terminology of HGP onto the concepts used in software engineering, how to model the different aspects of HGP as part of a data meta-model, what necessary steps in a potential HGP workflow can be identified, and, what kind of support can be offered to the designer.
Isikveren, Askin T., Ziemer, Sven, Stenz, Gernot, Hornung, Mirko
An Overview of the V&V of Flight-Critical Systems Effort at NASA2011-01-256010/18/2011
As the US is getting ready for the Next Generation (NextGen) of Air Traffic System, there is a growing concern that the current techniques for verification and validation will not be adequate for the changes to come. The JPDO (in charge of implementing NextGen) has given NASA a mandate to address the problem and it resulted in the formulation of the V&V of Flight-Critical Systems effort. This research effort is divided into four themes: argument-based safety assurance, distributed systems, authority and autonomy, and, software intensive systems. This paper presents an overview of the technologies that will address the problem.
Brat, Guillaume
FLIGHT TEST PROCEDURES FOR STATIC PRESSURE SYSTEMS INSTALLED IN SUBSONIC TRANSPORT AIRCRAFTARP921 (Historical)8/10/2011
This Aerospace Recommended Practice covers the test procedures and equipment for performing flight testing on pitot-static systems installed in subsonic transport type aircraft.
A-4 Aircraft Instruments Committee
Challenges in Validating Safety-Critical Embedded Systems2009-01-328411/10/2009
The embedded software has played an increasing role in safety-critical systems. At the same time the current development process of “build, then integrate” has proven unaffordable for the Aerospace industry. This paper outlines challenges in safety-critical embedded systems in addressing system-level faults that are currently discovered late in the development life cycle. We then discuss an architecture-centric approach to model-based engineering, i.e., to complement the validation of systems with analysis of different operational quality aspects from an architecture model. A key technology in this approach is the Architecture Analysis & Design Language (AADL), an SAE International standard for embedded software system. It supports analysis of operational qualities such as responsiveness, safety-criticality, security, and reliability through model annotations. A number of industry initiatives have been underway to demonstrate the feasibility of using this technology in industrial practice.
Feiler, Peter H.
Method and System for Making a Fuel-tank Inert without an Inert Gas2009-01-313411/10/2009
In Chemistry “Inert” implies ‘not readily reactive with other elements; forming few or no chemical compounds or something that is not chemically active’. “Inerting” is the process that renders a substance inert. A method for making a fuel-tank inert without the use of an inert gas is described. In this method fuel-air ratio of ullage is reduced until it becomes inert. The method does not discharge fuel vapors as an inert gas inerting system. Two systems employing the method are described explaining their pros and cons. Advantages of the method over Nitrogen Enriched Air (NEA) inerting method with an On-board Inert Gas Generating System (OBIGGS) are discussed. Patent application on the method and system is pending.
Gupta, Alankar
Remote Servoed Air Data Instruments for Subsonic AircraftAS791 (Current)2/16/2008
This standard provides minimum performance criteria for air data instruments intended to provide cockpit indication of: a Indicated airspeed (Vi) b Computer airspeed (Vc) c True airspeed (Vt) d Equivalent airspeed (Ve) e Mach number (M) f Altitude (H) g Vertical speed (Hpr) h Maximum operating limit speed (Vmo) i True angle of attack (αt) j Free air temperature (Tfat) k Total temperature (Tt) These functions shall be derived from a central air data computer (AS 417) and through system wiring applied to the respective indicator.
A-4 Aircraft Instruments Committee
MINIMUM SAFE PERFORMANCE OVER SPEED WARNING INSTRUMENTSAS8007 (Current)2/16/2008
This AS defines instruments which use inputs of static and pitot pressure equal to those which are utilized to establish the pressure altitude and speed of that aircraft. These pressures are applied to the instrument ports to provide means for generation of an aural warning whenever the aircraft reaches or exceeds the maximum operating limit speed. This Over Speed Warning Instrument function may be incorporated as part of an Air Data Computer, or an Air Speed Indicator, or an Air Speed/Mach Number Indicator, or other instruments. In those cases where the Over Speed Warning Instrument is part of another instrument, the standards contained herein apply only to the Over Speed Warning Instrument function. Each aircraft type and model has a defined maximum operating limit speed curve or curves which are a part of the airframe manufacturer's type certification approval data; this limit speed data shall be available from the subject airframe manufacturer as published in the operating manual for the aircraft type and model number and configuration.
A-4 Air Data Subcommittee
Air Data Computers, MPSAS417A (Current)2/16/2008
This Standard covers air data equipment (hereinafter designated the instrument) which when connected to sources of aircraft electrical power, static pressure, total pressure and outside air temperature (singly or in combination) provides some or all of the following computed air data output signals: Pressure Altitude* Total Temperature* Pressure Altitude (Reporting) Altitude Rate Baro-Corrected Pressure Altitude* Overspeed Warning Vertical Speed* Altitude Hold Computed Airspeed* Airspeed Hold Mach Number* Mach Hold Maximum Allowable Airspeed* qc (impact pressure) Static Air Temperature (*when used as an alternate for total temperature) True Airspeed Others
A-4 Aircraft Instruments Committee
FLIGHT DECK PANELS, CONTROLS, AND DISPLAYSARP4102 (Current)7/10/2007
This document recommends criteria for the design, installation and operation of panels, controls, and displays on the flight deck of transport aircraft.
S-7 Flight Deck Handling Qualities Stds for Trans Aircraft
Guidelines for Time-Limited-Dispatch (TLD) Analysis for Electronic Engine Control SystemsARP5107B (Historical)11/15/2006
This SAE Aerospace Recommended Practice (ARP) provides methodologies and approaches which have been used for conducting and documenting the analyses associated with the application of Time Limited Dispatch (TLD) to the thrust control reliability of Full Authority Digital Electronic Control (FADEC) systems. The TLD concept is one wherein a redundant system is allowed to operate for a predetermined length of time with faults present in the redundant elements of the system, before repairs are required. This document includes the background of the development of TLD, the structure of TLD that was developed and implemented on present generation commercial transports, and the analysis methods used to validate the application of TLD on present day FADEC equipped aircraft. Although this document is specific to TLD analyses (for FADEC systems) of the loss of thrust control, the techniques and processes discussed in this document are considered applicable to other FADEC system failure effects or other systems, such as, thrust reverser, and propeller control systems, and overspeed protection systems.
E-36 Electronic Engine Controls Committee
Laboratory and Preliminary In-Flight Tests of Electromechanical Actuators2006-01-24148/30/2006
This paper presents tests of Electromechanical Actuators (EMA) designed in the Department of Avionics and Control at the Rzeszow University of Technology. Also, the architecture of the laboratory stand as well as testing methods and obtained results are described. Furthermore, the paper discusses the in-flight test results of the complete set of servos installed as a part of the experimental Fly-By-Wire (FBW) control system on board of the PZL-110 “Koliber” aircraft.
Rzucidlo, Pawel
Fault Detection and Isolation in Attitude and Heading Reference Systems For Fly-By-Wire Control System For General Aviation Aircraft2006-01-24158/30/2006
The article presents problems of fault detection and isolation in AHRS systems for the Fly-By-Wire control system for general aviation. The system is currently being designed at the Rzeszów University of Technology. The idea of the system is to create a general aviation pilot-friendly aircraft. The FBW control system is equipped with three AHRSs. Their diagnostics is realized on three levels. The article describes hardware redundancy and software redundancy for AHRS systems and then shows how to use it for diagnostics. The article focuses especially on estimation techniques applied in research. For simulations data from flight tests were used.
Kopecki, Grzegorz, Dolega, Boguslaw
A Simple Analytical Redundancy Method for Pitch and Bank Angles Estimation2005-01-336210/3/2005
The article presents the idea of Pitch and Bank Angles estimation with the use of incomplete measurement information. This idea is applied in Attitude and Heading Reference Systems used in the Fly-By-Wire control system for a general aviation aircraft. The idea of the Fly-By-Wire control system for a general aviation aircraft designed in the Department of Avionics and Control Systems is presented in brief. For estimations Lunenberger observers were used. Simulation results are based on the flight test data.
Kopecki, Grzegorz, Tomczyk, Andrzej
Pressure Altimeter SystemsAS8009B (Historical)9/21/2005
This SAE Aerospace Standard (AS) specifies minimum performance requirements for primary pressure altimeter systems other than air data computers. This document covers altimeter systems that measure and display altitude as a function of atmospheric pressure. The pressure transducer may be contained within the instrument display case or located remotely. Requirements for air data computers are specified in AS8002. Some requirements for nontransducing servoed altitude indicators are included in AS791. The instrument system specified herein does not include aircraft pressure lines. Unless otherwise specified, whenever the term “instrument” is used, it is to be understood to be the complete system of pressure transducer components, any auxiliary equipment, and display components. The test procedures specified herein apply specifically to analog type instruments. Digital instruments or automatic test instrumentation may require other test procedures. Such differing procedures shall be justified prior to use.
A-4 Air Data Subcommittee
Guidelines for Time-Limited-Dispatch (TLD) Analysis for Electronic Engine Control SystemsARP5107A (Historical)1/28/2005
This SAE Aerospace Recommended Practice (ARP) provides methodologies and approaches which have been used for conducting and documenting the analyses associated with the application of Time Limited Dispatch (TLD) to the thrust control reliability of Full Authority Digital Electronic Control (FADEC) systems. The TLD concept is one wherein a redundant system is allowed to operate for a predetermined length of time with faults present in the redundant elements of the system, before repairs are required. This document includes the background of the development of TLD, the structure of TLD that was developed and implemented on present generation commercial transports, and the analysis methods used to validate the application of TLD on present day FADEC equipped aircraft. Although this document is specific to TLD analyses (for FADEC systems) of the loss of thrust control, the techniques and processes discussed in this document are considered applicable to other FADEC system failure effects or other systems, such as, thrust reverser, and propeller control systems, and overspeed protection systems.
E-36 Electronic Engine Controls Committee
GNSS NAVIGATION AND LANDING UNIT (GNLU)ARINC756-3 (Current)2/27/2004
This standard describes the function of the GNLU, capable of providing enroute/terminal navigation, non-precision approach, and precision approach capabilities. The GNLS consists of a GNLU, associated controls and displays, antenna, and interfaces to other aircraft systems.
Airlines Electronic Engineering Committee
A History of Ice Protection System Development at Sikorsky Aircraft2003-01-20926/16/2003
Modern rotorcraft must have the capability to operate in all-weather conditions. Sikorsky Aircraft has conducted icing research and ice protection system development for helicopters over the past 58 years and the pace of that work has accelerated during the past two decades. Sikorsky participated in several helicopter icing flight tests, conducted wind tunnel tests of scale models and full-scale components, tested simulated ice shapes, and developed analytical tools for use in the design, certification, and qualification for flight in icing conditions. Engine inlets, airspeed systems, main rotor droop stops, and windshields are generally protected by thermal anti-icing systems. When rotor ice protection is required, rotors are protected with electrothermal deice systems. The UH-60A BLACK HAWK electrothermal rotor ice protection system, developed in the late 1970s, has been installed in 2400 H-60 helicopters and it remains one of the most effective rotor ice protection systems. This paper traces the history of Sikorsky icing tests, presents information on the development of the BLACK HAWK rotor ice protection system, discusses data acquired during model-scale and full-scale airfoil and rotor icing tests, describes methods used to support ice protection system development and qualification/certification, and includes the status of BLACK HAWK Growth Rotor Blade icing qualification and S-92 icing certification.
Flemming, Robert J.
Assessment of the Dynamic Stability Characteristics of the Bell Model M427 Helicopter Using Parameter Estimation Technology2002-01-291611/5/2002
A joint program between Bell Helicopter Textron Canada and the Flight Research Laboratory of Canada's National Research Council was initiated to address the aerodynamic modelling challenges of the Bell M427 helicopter. The primary objective was to use the NRC parameter estimation technique, based on modified maximum likelihood estimation (MMLE), on a limited set of flight test data to efficiently develop an accurate forward-flight mathematical model of the Bell M427. The effect of main rotor design changes on the aircraft stability characteristics was also investigated, using parameter estimation. This program has demonstrated the feasibility of creating a forward-flight rotorcraft aerodynamic mathematical model based on time-domain parameter estimation, and the ability of a 6 degree-of-freedom MMLE model to accurately document the impact of minor rotor modifications on aircraft stability.
Hui, Kenneth, Ricciardi, Joseph, Srinivasan, Ramesh, Lambert, Edward, Sarafian, Ara
ATN Airborne Implementation2002-01-295811/5/2002
Hamel, Christophe, Judd, Tom, Nguyen, Ketan, Rowe, Bryan, Wohlers, Kevin
AIRBORNE COMPUTER HIGH SPEED DATA LOADERARINC615-4_ER2 (Current)5/6/2002
This standard provides general and specific guidance for the development of a Portable Data Loader (PDL) for carry-on application and an Airborne Data Loader (ADL) for on-board the airplane. It specifies use of a 3.5 inch floppy disk to upload and download of data and operational programs using an ARINC 429 data bus connected to avionics computers.
Airlines Electronic Engineering Committee
562 Terrain Awareness and Warning System (TAWS) - AnalogARINC562 (Current)12/1/2001
Terrain Awareness and Warning System (TAWS) Analog addresses the need for standard TAWS installations in older aircraft that have analog equipment interfaces. The analog unit is intended as a replacement for ARINC Characteristic 594: Ground Proximity Warning System (GPWS) equipment. The document is intended to compliment ARINC Characteristic 762: Terrain Awareness and Warning System (TAWS) for later model aircraft having digital equipment interfaces.
Airlines Electronic Engineering Committee
Unusual Attitude Recovery Using the Roll Arrow2001-01-30099/11/2001
As part of the NASA High Speed Research program, an unusual attitude (UA), pilot-in-the-loop simulation study provided information on Primary Flight Display (PFD) symbology factors that affect UA recovery. Overall research objectives were to evaluate symbology concepts to facilitate pilot perception and safe recovery. It was concluded that UA recognition and recovery task performance is unacceptable when the pilot relies only on raw data but is improved markedly with appropriate second-generation symbology. The major result indicated that a newly-developed PFD symbol (the Roll Arrow) significantly reduced UA recognition errors. The Roll Arrow is a large, red arrow attached to the PFD Bank Angle Pointer. When the aircraft is in a UA, the Roll Arrow appears on the PFD and points left or right to indicate the required direction to roll for recovery. Other recovery actions are at pilot discretion. In comparison to other evaluated symbology designs, the Roll Arrow was associated with 90% reduction in pilot error. Workload, situation awareness, and pilot opinion all favored the Roll Arrow.
Gershzohn, Gary
AIR DATA AND INERTIAL REFERENCE SYSTEM (ADIRS)ARINC738A-1 (Current)7/31/2001
This standard sets forth characteristics for a 4 MCU integrated digital ADIRS intended for installation in subsonic commercial transport aircraft. It is envisioned that the ADIRS will incorporate the capabilities of both an air data system and an inertial reference system.
Airlines Electronic Engineering Committee
GUIDANCE FOR TOOL AND TEST EQUIPMENT (TTE) EQUIVALENCYARINC738-3 (Current)7/1/2001
This standard defines an integrated ADIRS that provides air data information and directional guidance information for cockpit display. The ADIRS consists of up to three Air Data/Inertial Reference Units (ADIRUs) located in the aircraft electronic rack, an associated Control and Display Unit (CDU) and remotely mounted Air Data Modules (ADMs).
Airlines Electronic Engineering Committee
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