1、FLIGHT WARNINGCOMPUTER SYSTEMARINC CHARACTERISTIC 726-1PUBLISHED: SEPTEMBER 10, 1981AN a DOCUMENTPrepared byAIRLINES ELECTRONIC ENGINEERING COMMITTEEPublished byAERONAUTICAL RADIO, INC.2551 RIVA ROAD, ANNAPOLIS, MARYLAND 21401REPLACEMENT PAGE REVISED: September 8, 1980AERONAUTICAL RADIO, INC.2551 Ri
2、va RoadAnnapolis, MD 21401ARINC CHARACTERISTIC 726-1FLIGHT WARNING COMPUTER SYSTEMARINC Characteristic 726-1 was first published on: September 10, 1981Prepared by the Airlines Electronic Engineering CommitteeCharacteristic 726 Adopted by the Airlines Electronic Engineering Committee:August 30, 1979C
3、haracteristic 726 Adopted by Industry: October 31, 1979Characteristic 726-1 Adopted by the Airlines Electronic Engineering Committee:June 19, 1980REPLACEMENT PAGE REVISED: September 8, 1980ARINC CHARACTERISTIC 726TABLE OF CONTENTSiiiITEM SUBJECT PAGE1.0 INTRODUCTION 11.1 Purpose of This Document 11.
4、2 Summary of Operational Characteristics 11.3 Brief Description of the System 11.3.1 Flight Warning Computer Unit (FWCU) 11.3.2 Warning and Caution Display 11.3.3 Status and Maintenance Panel 11.3.4 Additional Warning and Caution Lights 11.3.5 Miscellaneous Inputs 11.4 Interchangeability 11.4.1 Gene
5、ral 11.4.2 Interchangeability Desired for the ARINC 726 FWCS 21.4.3 “Generation Interchangeability” Considerations 21.5 Regulatory Approval 22.0 INTERCHANGEABILITY STANDARDS 32.1 Introduction 32.2 Form Factors, Connectors and Index Pin Coding 32.2.1 Flight Warning Computer Unit (FWCU) 32.2.2 Warning
6、 and Caution Display 3-42.3 Interwiring 42.4 Power Circuitry 42.4.1 Primary Power Input 42.4.2 Power Control Circuitry 42.4.3 The Common Ground 42.4.4 The AC Common Cold 42.5 Systems Functions and Signal Characteristics 42.6 Environmental Conditions 42.7 Cooling 42.7.1 FWCU Cooling 4-52.7.2 Warning
7、and Caution Display 52.8 Grounding and Bonding 53.0 SYSTEM DESIGN 63.1 Basic Philosophy of the FWCS 63.2 System Functions 63.2.1 General Functions 63.2.1.1 Cancel/Storage 63.2.1.2 Recall 63.2.1.3 Intelligence 63.2.1.4 Re-grading 63.2.1.5 Inhibiting 63.2.1.6 Self Test 63.2.1.7 Ground Test 83.2.2 Flig
8、ht Alert Functions 83.2.2.1 Configuration 83.2.2.2 Overspeed 83.2.2.3 Minimum Speed 83.2.2.4 Altitude Alert 83.2.2.5 Windshear 83.2.2.6 Ground Proximity 83.2.2.7 Collision Avoidance 83.3 Aircraft Systems Alert Functions 93.4 System Architecture 94.0 STANDARD SIGNAL CHARACTERISTICS 104.1 General Accu
9、racy and Operating Ranges 104.1.1 Digital Data Standards 104.1.2 Synchro Standards 104.1.3 Standard “Applied” Voltage 104.1.4 Standard “Ground”/”Open” Signal 104.1.5 Low Level DC Signal Standard 104.2 System Inputs 104.2.1 Radio Altimeter Bus 10TABLE OF CONTENTS (contd)ivITEM SUBJECT PAGE4.2.2 Radio
10、 Altimeter Bus 104.2.3 IRS or AHRS Bus 104.2.4 ILS Bus 104.2.5 Engine/Fuel/Airframe Data Bus 104.2.6 Crosstalk Bus 104.2.7 Warning and Caution Display Bus 104.2.8 FCC Inputs 104.2.9 TCC Bus 104.2.10 Spare Input Ports 104.2.11 Analog Inputs 114.2.11.1 Low Level DC Inputs 114.2.11.2 Synchro Inputs 114
11、.2.11.3 Discrete Inputs 114.3 System Outputs 114.3.1 Warning and Caution Display Buses 114.3.2 Crosstalk Bus 114.3.3 AIDS or Maintenance Bus 114.3.4 Stick Shaker Output 114.3.5 Miscellaneous Discretes 114.3.6 Audio Output 114.3.7 Automatic Volume Control 115.0 AUDIBLE WARNING GENERATION 125.1 Genera
12、l 125.2 Audible Warning Generation Functions 125.2.1 Autopilot Disconnect Warning 125.2.2 Stall 125.2.3 Ground Proximity Warning and Glide Slope Deviation Alert 125.2.4 Attenson 125.2.5 Reset 125.2.6 Emergency Audio Cancel 125.2.7 Monitoring 125.2.8 Priorities 12-136.0 WARNING AND CAUTION DISPLAY (W
13、CD) 146.1 General 146.2 Display Technology 146.3 Brightness Control 146.4 Warning and Caution Display Interfaces 147.0 LOGIC STANDARDIZATION 158.0 PROVISIONS FOR AUTOMATIC TEST EQUIPMENT 168.1 General 168.2 Unit Identification 168.2.1 Pin Allocation 168.2.2 Use of ATLAS Language 16ATTACHMENTS1A Flig
14、ht Warning Computer System Architectures 171B FWC Connector Placement 182 Standard Interwiring 19-29Notes Applicable To The Standard Interwiring 30-31Connector Insert Pin Layouts 32-363 Flight Warning System Specification of Digital Data Transfer 374-1 Flight Phase Adaptation 38-404-2 Classification
15、 of Flight Warning Functions 41-475-1 Typical Programmable Inputs Assignments Lists 48-535-2 Typical Programmable Output Applications 546 Inputs Distribution 557 Environmental Test Categories 568-1 Audible Warning Function 57-588-2 A.W.G. Sounds Definition 59-60APPENDIX1 Chronology And Bibliography
16、61-62ARINC CHARACTERISTIC 726 - Page 11.0 INTRODUCTION1.1 Purpose of This DocumentThis document sets forth the characteristics of a FlightWarning Computer System (FWCS) intended for use incommercial transport aircraft.The intent of this document is to provide general andspecific design guidance for
17、the development andinstallation of a FWCS primarily for airline use. It willdescribe the desired operational capability of the systemand the standards necessary to ensure the level ofinterchangeability specified in Section 1.4.Equipment manufacturers should note that this documentencourages them to
18、produce maintenance-free, high-performance equipment. They are at liberty to accomplishthis objective by means of design techniques they considerto be the most appropriate, as their airline customers areinterested primarily in the end result rather than the meansemployed to achieve it.COMMENTARYAler
19、ting devices are provided in aircraft to drawthe flight crews attention to the onset ofconditions which, if left unchanged, could causeoperational difficulties or prejudice the continuedsafety of the flight. The circumstances in whichalerts are generated are determined from safetyand operational ana
20、lyses or are dictated byairworthiness authorities. Typical examples ofwarnings given to the flight crew are: stallwarning, configuration warning, landing gearwarning, cabin altitude and pressure,VMO/MMO, fuel pressure warning, oil pressurewarning and fire warnings.1.2 Summary of Operational Characte
21、risticsThe Flight Warning Computer System (FWCS) describedherein is intended to process caution and warning inputsfor visual and/or audible presentation to the flight crew.In one specific case (the stall warning stick shaker), tactilepresentation is used. The operational guidance containedin the Soc
22、iety of Automotive Engineers documentARP450D, “Integrated Flight Deck Alerting Systems” hasbeen followed in determining the functional specificationfor the system.1.3 Brief Description of the SystemThe FWCS may consist of one or two Flight WarningComputer Units (FWCUs) and appropriate combinationsof
23、 the other units described in this Section, as determinedby the system designer. The single computer installationis expected to suffice in simple aircraft. The dualcomputer installation may be needed in more complexaircraft. Attachment 1 to this document shows typicalsystem architectures.The two com
24、puters of the dual computer architecture areidentical and interchangeable. Essential warnings areacquired and processed by both computers redundantly.The acquisition and processing of other warnings andcautions are shared between them. This arrangementprovides the optimum dispatchability and reliabi
25、lity andthe minimum spares provisioning burden. Attachment 6to this document shows how the system handles differenttypes of warning inputs.1.3.1 Flight Warning Computer Unit (FWCU)The FWCU contains logic to process warning inputs andto perform flight phase inhibit and priority switchingfunctions. It
26、 also contains the circuitry to generateaudible warning sounds and a coded digital output for useby visual warning and caution displays.1.3.2 Warning and Caution DisplayWarning and caution information will be presented to theflight crew on one or more alpha/numeric displays and bymeans of essential
27、caution and warning lights which mayor may not be located on these displays. In many, if notmost, FWCS installations, the primary visualalpha/numeric display will be provided on one of theCRTs of a multi-CRT electronic instrumentation system.The FWCU coded digital output data will be translatedinto
28、alpha/numeric format in the designated symbolgenerator unit of that system. In installations in aircraftnot equipped with such comprehensive CRT displayfacilities, it will be necessary to provide dedicateddisplay(s) which incorporate the ability to translate theFWCUs coded output into alpha/numerics
29、. See Chapter6 of this document for further details.1.3.3 Status and Maintenance PanelThe Status and Maintenance Panel provides a humaninterface for the FWCS BITE. It consists of a display andcontrol unit for initiation of automated test, post-flightrecall of inflight failures and presentation of in
30、structionsfor maintenance action. If desired, its functions may beintegrated with other systems status/maintenanceinformation facilities at a central location on the aircraft.1.3.4 Additional Warning and Caution LightsWarning and caution lights, additional to the essentiallights specified in Section
31、 1.3.2 above, will be installed inthe glareshield (or elsewhere in the cockpit), as the needsof the system dictate.1.3.5 Miscellaneous InputsInput facilities should be provided to meet system designneeds such as:- Emergency audio cancel- Recall (if not installed on th e display)1.4 Interchangeabilit
32、y1.4.1 GeneralOne of the primary functions of an ARINC EquipmentCharacteristic is to designate, in addition to certainperformance parameters, the interchangeability desired foraircraft equipment produced by various manufacturers.Manufacturers are referred to Section 1.6 of ARINCReport 414 for the ai
33、rline industrys definitions of Termsand General Requirements for interchangeability. Asexplained in that Report, the degree of interchangeabilityconsidered necessary and attainable for each particularequipment is specified in the pertinent ARINC EquipmentCharacteristic.ARINC CHARACTERISTIC 726 - Pag
34、e 21.0 INTRODUCTION (contd)1.4.2 Interchangeability Desired for the ARINC 726FWCSLimited unit interchangeability is desired for the FWCUin the programmed state, i.e., the unit should beinterchangeable between the various models (dashnumbers) of an aircraft type. Complete unitinterchangeability is de
35、sired for the unit in theunprogrammed state, i.e., any ARINC 726 FWCU shouldbe capable of being programmed to function properly onany aircraft type.COMMENTARYThe airlines recognize that their desire for full unitinterchangeability of the FWCU must be temperedby the fact that software differences wil
36、l be neededto accommodate the different characteristics of theaircraft types in which it will be installed.1.4.3 “Generation Interchangeability” ConsiderationsThe airlines desire future evolutionary equipmentimprovements and the inclusion of any additionalfunctions in new equipments during the next
37、few years tobe achieved without violating the interwiring and formfactor standards set forth in this document. Provisions toensure forward-looking “generation interchangeability”(as best can be predicted) are included in this document toguide manufacturers in these future developments.1.5 Regulatory
38、 ApprovalThe equipment should meet all applicable regulatoryrequirements. This Characteristic does not and cannot setforth the specific requirements that an equipment mustmeet to be assured of government regulatory agencyapproval. Such information must be obtained fromgovernment regulatory agencies
39、directly.REPLACEMENT PAGE REVISED: September 8, 1980ARINC CHARACTERISTIC 726 - Page 32.0 INTERCHANGEABILITY STANDARDS2.1 IntroductionThis section of this Characteristic sets forth the specificform factors, mounting provisions, interwiring, input andoutput interfaces and power supply characteristics
40、desiredfor the complete Flight Warning Computer System.These standards are necessary to ensure the continuedindependent design and development of both theequipment and the airframe installations.Manufacturers should note that although thisCharacteristic does not preclude the use of different formfac
41、tors and interwiring features, the practical problem ofredesigning what will then be a standard aircraftinstallation to accommodate some special system couldvery well make the use of that other design prohibitivelyexpensive for the customer. They should recognize,therefore, the practical advantages
42、of developingequipment in accordance with the form factor, interwiringand signal standards of this document.2.2 Form Factors, Connectors and Index Pin Coding2.2.1 Flight Warning Computer Unit (FWCU)The FWCU should comply with the dimensionalstandards in ARINC Specification 600, “Air, TransportAvioni
43、cs Equipment Interfaces (NIC Phase I)”, for the 6MCU form factor. The FWCU should also comply withARINC 600 standards in respect of weight, rackingattachments, front and rear projections and cooling.The FWCU should be provided with a low insertion force,size 3 shell ARINC 600 service connector. This
44、connector should be located on the center grid of theFWCU rear panel, and index pin code 03 should be used.The top and center inserts of this connector (LTP, RTP,LMP and RMP) should each provide 150 contacts. Thelower inserts (LBP and RBP should provide 11 singlecontacts and spaces for two small-dia
45、meter coaxialcontacts. Attachment 1A to this document shows theconnector arrangement and Attachment 2 the pinassignments.If functions not assigned pins on the service connector inAttachment 2 to this document are needed to be broughtto the “outside world” to facilitate testing the FWCU withautomatic
46、 test equipment (ATE), they should be assignedpins on auxiliary connector whose type and location isselected by the equipment manufacturer. Themanufacturer should observe the standards of ARINCSpecification 600 when choosing the location for thisconnector and note that, other than to accommodate the
47、needs for equipment identification by the ATE describedin Section 8.2 of this document, he is free to makewhatever pin assignments on it he wishes. The airlines donot want the unassigned (“future spare”) pins of theservice connector used for functions associated solelywith ATE use.NOTE: The combinat
48、ion of pin density and terminationscan make connections susceptible to short circuitfaults between adjacent pins. Such a fault couldresult in a false warning being “triggered” inparallel with a true warning. Should such a faultresult in an extra2.2.1 Flight Warning Computer Unit (FWCU) (contd)NOTE:
49、drive to the display of a real warning, no prob-(contd) lem would exist. However, the same will not betrue if the result is a “false” display warning inconjunction with a true warning. Whenallocating pins on any connector, includingthose on internal wiring terminations andprinted circuit boards, the following segregationpriority should be observed.Any pin to adjacent pin short resulting in aTRUE warning plus:1. Any false Emergency Engine Warningshould be considered as unacceptable.2. Any false Emergency Warning (notinhibi
