1、 WINDSHEAR WARNING ANDGUIDANCE SYSTEMARINC CHARACTERISTIC 742PUBLISHED: JANUARY 27, 1988AN DOCUMENTPrepared byAIRLINES ELECTRONIC ENGINEERING COMMITTEEPublished byAERONAUTICAL RADIO, INC.2551 RIVA ROAD, ANNAPOLIS, MARYLAND 21401This document is based on material submitted by various participantsduri
2、ng the drafting process. Neither AEEC nor ARINC has made anydetermination whether these materials could be subject to claims ofpatent or other proprietary rights by third parties, and norepresentation or warranty, express or implied, is made in this regard.Any use of or reliance on this document sha
3、ll constitute anacceptance hereof “as is“ and be subject to this disclaimer.Copyright 1992 byAERONAUTICAL RADIO, INC.2551 Riva RoadAnnapolis, Maryland 21401ARINC CHARACTERISTIC 742 WINDSHEAR WARNING AND GUIDANCE SYSTEMPublished: January 27, 1988Prepared by the Airlines Electronic Engineering Committ
4、ee:Characteristic 742 Adopted by the Airlines Electronic Engineering Committee: October 14, 1987iiFOREWORDActivities of AERONAUTICAL RADIO, INC. (ARINC)and thePurpose of ARINC CharacteristicsAeronautical Radio, Inc. is a corporation in which the United States scheduled airlines are the principalstoc
5、kholders. Other stockholders include a variety of other air transport companies, aircraft manufacturers and foreignflag airlines.Activities of ARINC include the operation of an extensive system of domestic and overseas aeronautical landradio stations, the fulfillment of systems requirements to accom
6、plish ground and airborne compatibility, the allocationand assignment of frequencies to meet those needs, the coordination incident to standard airborne communications andelectronics systems and the exchange of technical information. ARINC sponsors the Airlines Electronic EngineeringCommittee (AEEC)
7、, composed of airline technical personnel. The AEEC formulates standards for electronic equipmentand systems for the airlines. The establishment of Equipment Characteristics is a principal function of this Committee.An ARINC Equipment Characteristic is finalized after investigation and coordination
8、with the airlines whohave a requirement or anticipate a requirement with other aircraft operators, with the Military services having similarrequirements, and with the equipment manufacturers. It is released as an ARINC Equipment Characteristic only whenthe interested airline companies are in general
9、 agreement. Such a release does not commit any airline or ARINC topurchase equipment so described nor does it establish or indicate recognition of the existence of an operationalrequirement for such equipment, nor does it constitute endorsement of any manufacturers product designed or built tomeet t
10、he Characteristic. An ARINC Characteristic has a twofold purpose, which is:(1) To indicate to the prospective manufacturers of airline electronic equipment the considered opinion ofthe airline technical people, coordinated on an industry basis, concerning requisites of new equipment,and(2) To channe
11、l new equipment designs in a direction which can result in the maximum possiblestandardization of those physical and electrical characteristics which influence interchangeability ofequipment without seriously hampering engineering initiative.ARINC CHARACTERISTIC 742TABLE OF CONTENTSITEM SUBJECT PAGE
12、iii1.0 INTRODUCTION AND DESCRIPTION 11.1 Purpose of This Document 11.2 Summary of Windshear Warning System Operational Characteristics 11.3 Brief Description of the System 11.4 Interchangeability 11.5 Regulatory Approval 12.0 INTERCHANGEABILITY STANDARDS 22.1 Introduction 22.2 Form Factor, Connector
13、s and Index Pin Coding 22.3 Standard Interwiring 22.4 Power Circuitry 22.4.1 Primary Power Input 22.4.2 Power Control Circuitry 22.4.3 The AC Common Cold 22.4.4 The Common Ground 22.5 Environmental Conditions 22.6 Cooling 22.7 Grounding and Bonding 23.0 SYSTEM DESCRIPTION 33.1 Operation 33.1.1 Winds
14、hear Audible Warning 33.1.2 Windshear Visual Warning 33.1.3 Windshear Guidance (Optional) 33.2 Operating Modes 33.3 Monitoring 43.3.1 Self-Test 43.3.2 Monitor Output 43.4 Signal Outputs 43.4.1 Windshear Visual Discrete Outputs 43.4.1.1 Caution Output 43.4.1.2 Warning Output 43.4.2 Windshear Audible
15、Warnings 43.4.3 Flight Director Pitch Guidance (Optional) 44.0 STANDARD SIGNAL CHARACTERISTICS 54.1 General Accuracy and Operating Ranges 54.1.1 Digital Data Standards 54.1.2 Synchro Standards 54.1.3 Standard “Open” 54.1.4 Standard “Ground” Signal 54.1.5 Standard “Applied Voltage” 54.1.6 Standard Di
16、screte Input 54.1.7 Discrete Output 54.1.7.1 Open/Ground Discrete Output 5-64.1.7.2 Open/Voltage Discrete Output 64.2 System Inputs 64.2.1 Radio Altitude 64.2.2 Air Data 64.2.3 IRS or AHRS Bus 64.2.4 Indicated Angle of Attack Sensor 64.2.5 Flap Position 64.2.6 Attitude 64.2.7 Wheel Speed 64.2.8 Engi
17、ne EPR/N1/N2/N3 64.2.9 Program Inputs 64.2.10 Discrete Input 64.2.10.1 Flight Director Status Discrete Input 64.2.10.2 Flap Position Discrete Input 74.2.10.3 Radio Altitude Valid Discrete Input 74.2.10.4 Radio Altitude Trip Point Discrete Input 74.2.10.5 R/P Gyro Valid Discrete Input 74.2.10.6 AOA P
18、ickoff Valid Input 74.2.10.7 Unspecified Discrete Input 74.2.10.8 TOGA Switch Discrete Inputs 74.2.10.9 Air/Ground Discrete Input 74.2.10.10 Gear Position Discrete Input 74.2.10.11 Self-Test Discrete Input 7ARINC CHARACTERISTIC 742TABLE OF CONTENTS (contd)ITEM SUBJECT PAGEiv4.3 System Outputs 74.3.1
19、 Discretes 74.3.1.1 Caution Discrete Output 74.3.1.2 Warning Discrete Output 74.3.1.3 Roll Select Discrete Output 74.3.1.4 Pitch Select Discrete Output 74.3.1.5 Fast/Slow Select Output 74.3.1.6 GPWS Inhibit Discrete Output 74.3.1.7 WWS Fail Discrete 84.3.2 Audio Output 8ATTACHMENTS1 WWC Connector Po
20、sitioning 92.1 Standard Interwiring 10-172.2 Notes to Standard Interwiring 182.3 Connector Insert Layout 19-213 Environmental Test Categories 22ARINC CHAR ACTERISTIC 742 - Page 11.0 INTRODUCTION1.1 Purpose of This DocumentThis document describes a stand-alone windshear warningsystem (WWS) specifical
21、ly designed for retrofitinstallation in commercial type aircraft having primarilyanalog interfaces. The system is comprised of a basicsingle airborne element, designated the windshear warningcomputer (WWC), which uses data pertaining to aircraftmovement with respect to air movement to detect andannu
22、nciate a windshear condition. The system, as anoption, may also provide instrument guidance to the crewindicating optimum pitch to endure the encounter.This document provides general and specific designguidance for the development and installation of awindshear warning system. It describes the desir
23、edoperational capability of the system and the standardsnecessary to achieve interchangeability of hardware.Equipment manufacturers should note that this documentencourages them to produce maintenance-free, high-performance equipment rather than that of minimumweight and size. They are at liberty to
24、 accomplish thisobjective by means of the techniques they consider to bethe most appropriate. The airlines customers areinterested primarily in the end result rather than the meansemployed to achieve it.1.2 Summary of Windshear Warning SystemOperational CharacteristicsThe windshear warning system de
25、scribed herein is an aidto pilots. It should provide audible and visible warningsor alerts, as well as optional recovery guidance when anaircraft is subject to hazardous low level windshear. Itshould maintain the appropriate outputs until the aircrafthas exited the area of potential danger.1.3 Brief
26、 Description of the SystemThe windshear warning system addressed in thisCharacteristic is intended for retrofit in installations wherethe interface is primarily analog. It should consist of ansingle rack-mounted windshear warning computer(WWC) unit that houses all of the components, electroniccircui
27、try, etc., incident to the functioning of the system.It should accept inputs of radio height, barometricaltitude, pitch and roll attitude, airspeed, horizontal andvertical accelerations, Angle-of-Attack (AOA), Machnumber, heading, barometric rate and logic related to thelanding gear and flap positio
28、ns to determine if ahazardous low level shear is developing. It may alsoprovide, as appropriate, sensors to obtain these functionalinputs. On sensing a hazardous windshear condition, thesystem should generate audio outputs and discreteoutputs. The discretes may be used to activate one ormore visual
29、alerting or warning devices. The system mayalso provide an optional pitch command for recoveryguidance.COMMENTARYTwo configurations of windshear warning systemsare expected. For existing airplanes which employanalog interfaces, a single rack1.3 Brief Description of the System (contd)COMMENTARY (cont
30、d)mounted unit, the WWC, defined in thisCharacteristic should be used. For aircraft whichemploy a digital interface, particularly ARINC 429,an architecture integrated into existing processingsystems is anticipated. Windshear warning systemsdeveloped for new aircraft are also expected to use adistrib
31、uted architecture. The candidate LRU favoredby the airlines for processing the windshear sensingalgorithms is the automatic flight control system(AFCS).Algorithms used to sense a windshear condition are notspecified by this Characteristic. The windshear sensingand alerting provisions called out for
32、the stand-alonesystem described herein should apply equally to anintegrated system.1.4 InterchangeabilitySystem interchangeability, as defined in Section 2.0 ofARINC Report 607, “Design Guidance for AvionicEquipment”, is desired for Windshear Warning System(WWS). The standards necessary to ensure th
33、is level ofinterchangeability are set forth in Chapter 2 of thisdocument.COMMENTARYManufacturers should strive to produce equipmentwith the capability of operating in more than oneairframe and/or configuration. If this goal isachieved, user airlines with several airplane typeswill need to carry spar
34、es for only one WWCconfiguration. Further, complete unit interchange-ability is desired for equipment from differentmanufacturers. It is recognized that there may bepressure from both equipment manufacturers andsome airlines to introduce differences in the WWCto accommodate specific airframe require
35、ments.These differences will reduce the potential forinterchangeability between fundamentally identicalunits.1.5 Regulatory ApprovalThe equipment should meet all applicable regulatoryrequirements. This Characteristic does not set forth thespecific requirements that an equipment must meet to beassure
36、d of certification. Such information should beobtained through the regulatory agency.ARINC CHARACTERISTIC 742 - Page 22.0 INTERCHANGEABILITY STANDARDS2.1 IntroductionThis Section of this Characteristic sets forth the specificform factor, mounting provisions, input and outputinterfaces and power supp
37、ly characteristics desired for thewindshear warning system. These standards provide forparallel but independent design of compatible equipmentand airframe installations.Manufacturers should note that although thisCharacteristic does not preclude the use of standardsdifferent from those set forth her
38、ein, the practicalproblems of redesigning an airframe installation toaccommodate special equipment could very well make theuse of the equipment prohibitively expensive for thecustomer. They should recognize, therefore, the practicaladvantages of developing equipment in accordance withthe guidance se
39、t forth in this document.2.2 Form Factor, Connectors and Index Pin CodingThe windshear warning system computer unit shouldcomply with the dimensional standards in ARINCSpecification 600, “Air Transport Avionics EquipmentInterfaces”, for the 4 MCU form factor. The computershould also comply with ARIN
40、C 600 standards in respectof weight, racking attachments, and front and rearprojections.The Windshear Warning Unit should be provided with alow insertion force size 2 shell ARINC 600 serviceconnector. This connector, which should accommodateservice interconnections in its bottom, middle and topinser
41、ts (BP, MP, and TP), should be located on the centerline of the units rear panel as shown in Attachment 1.Index pin code 07 should be used.If functions not assigned pin on the foregoing serviceconnector in Attachment 1 to this document are needed tofacilitate bench testing the unit with automatic te
42、stequipment (ATE), they should be located in the top 50pins of the top insert (TP).2.3 Standard InterwiringThe standard interwiring to be installed for the WWS isset forth in Attachment 2. It is recognized that eachairplane retrofitted with a windshear system will haveparameters and interfaces speci
43、fic to that airplane.Therefore, all interfaces listed in the standard interwiringlist will not be needed in every airplane. The standardwiring indicates the pins that should be used for each typeof interface if and when that interface exists on theairplane.2.4 Power Circuitry2.4.1 Primary Power Inpu
44、tThe equipment should be designed to use 115 volt 400 Hzsingle phase AC power. This primary power should beprotected by a single circuit breaker, normally situated inthe aircraft power distribution center.The aircraft power supply characteristics, utilization,equipment design limitations, and genera
45、l guidancematerial are set forth in ARINC Report2.4.1 Primary Power Input (contd)413A, “Guidance for Aircraft Electrical Power Utilizationand Transient Protection” and ARINC Report 609,“Design Guidance for Electrical Power Systems”.2.4.2 Power Control CircuitryThere should be no master on/off power
46、switching withinthe windshear warning system computer. Any userdesiring power on/off control for the unit should provide,through the medium of a switching function installed inthe airframe, means of interrupting the primary AC powerto the equipment. It should be noted that primary poweron/off switch
47、es for the windshear warning systemcomputer will not be needed in most installations, andpower will be wired directly to the equipment from thecircuit breaker panel.2.4.3 The AC Common ColdThe wire connected to the windshear warning systemcomputer connector pin labeled “115 VAC Cold” shouldbe ground
48、ed to the same structure that provides the DCchassis ground, but at a separate ground stud. Airframemanufacturers are advised to keep AC ground wires asshort as practicable in order to minimize noise pick-up.2.4.4 The Common GroundThe wire connected to the windshear warning systemcomputer connector
49、pin labeled “Chassis Ground” shouldbe employed as the DC ground return to aircraft structure.It is not intended as a common return for circuits carryingheavy AC currents, and equipment manufacturers shoulddesign their equipment accordingly.2.5 Environmental ConditionsThe WWC unit should be specified environmentally interms of the requirements of RTCA Document DO-160B,entitled “Environmental Conditions and Test Proceduresfor Airborne Equipment”, and EUROCAE ED-14B,entitled “Environmental Conditions and Test Proceduresfor Airborne Equipment”. Attachment 3 to thisCharacteristic tabul
