1、AELECTRONIC CHRONOMETERARINC CHARACTERISTIC 731-3PUBLISHED: NOVEMBER 30, 1998AN A DOCUMENTPrepared byAIRLINES ELECTRONIC ENGINEERING COMMITTEEPublished byAERONAUTICAL RADIO, INC.2551 RIVA ROAD, ANNAPOLIS, MARYLAND 21401-7465Copyright 1998 byAERONAUTICAL RADIO, INC.2551 Riva RoadAnnapolis, Maryland 2
2、1401-7465 USAARINC CHARACTERISTIC 731-3 ELECTRONIC CHRONOMETERPublished: November 30, 1998Prepared by the Airlin es Electronic Engineering CommitteeCharacteristic 731 Adopted by the Airlines Electronic Engineering Committee: June 19, 1980Characteristic 731 Adopted by the Industry: October 31, 1980Su
3、pplement Adopted Date PublishedCharacteristic 731-1 March 12, 1981 April 15, 1981Characteristic 731-2 December 10, 1981 October 31, 1983Characteristic 731-3 October 29, 1998 November 30, 1998A description of the changes introduced by each supplement is included (on Goldenrod paper) at the end of thi
4、s document. iiFOREWORDActivities of AERONAUTICAL RADIO, INC. (ARINC)and thePurpose of ARINC CharacteristicsAeronautical Radio, Inc. is a corporation in which the United States scheduled airlines are theprincipal stockholders. Other stockholders include a variety of other air transport companies,airc
5、raft manufacturers and non-U.S. airlines.Activities of ARINC include the operation of an extensive system of domestic and overseasaeronautical land radio stations, the fulfillment of systems requirements to accomplish ground andairborne compatibility, the allocation and assignment of frequencies to
6、meet those needs, thecoordination incident to standard airborne compatibility, the allocation and assignment offrequencies to meet those needs, the coordination incident to standard airborne communications andelectronics systems and the exchange of technical information. ARINC sponsors the AirlinesE
7、lectronic Engineering Committee (AEEC), composed of airline technical personnel. The AEECformulates standards for electronic equipment and systems for the airlines. The establishment ofEquipment Characteristics is a principal function of this Committee.An ARINC Equipment Characteristic is finalized
8、after investigation and coordination with theairlines who have a requirement or anticipate a requirement, with other aircraft operators, with theMilitary services having similar requirements, and with the equipment manufacturers. It is releasedas an ARINC Equipment Characteristic only when the inter
9、ested airline companies are in generalagreement. Such a release does not commit any airline or ARINC to purchase equipment sodescribed nor does it establish or indicate recognition of the existence of an operational requirementfor such equipment, nor does it constitute endorsement of any manufacture
10、rs product designed orbuilt to meet the Characteristic. An ARINC Characteristic has a twofold purpose, which is:(1) To indicate to the prospective manufacturers of airline electronic equipment theconsidered opinion of the airline technical people, coordinated on an industry basis,concerning requisit
11、es of new equipment, and(2) To channel new equipment designs in a direction which can result in the maximumpossible standardization of those physical and electrical characteristics whichinfluence interchangeability of equipment without seriously hampering engineeringinitiative.iiiARINC CHARACTERISTI
12、C 731TABLE OF CONTENTSITEM SUBJECT PAGE1.0 INTRODUCTION 11.1 Purpose of this Characteristic 11.2 Function of the Equipment 11.3 Reliability 11.4 Unit Description 11.5 Interchangeability 11.5.1 General 11.5.2 Interchangeab ility Desired 11.6 Regulatory Approval 12.0 INTERCHANGEABILITY STANDARDS 22.1
13、Form Factors and Connectors 22.2 Cooling 22.3 Signal Characteristics 22.4 Standards Interwiring 22.5 Power Circuitry 23.0 SYSTEM DESIGN CONSIDERATIONS 33.1 Utilizatio n Equipment Output 33.2 Warning Devices 33.3 Input Power 33.4 Lighting Power 33.5 Manual Setting (time, date and day) 33.6 Chronograp
14、h Control 33.7 Elapsed Time Control 33.8 Accuracy of the Electronic Chronometer 43.9 UTC Setting Accuracy 43.10 Ch ronograph Starting Accuracy 43.11 Elapsed Time Starting Accuracy 43.12 Clock Synchronization Time 44.0 DIGITAL SIGNAL CHARACTERISTICS 54.1 Digital Input Data 54.2 Digital Output Data 5A
15、TTACHMENTS1 Standard Interwiring 62 Notes Applicable to Standard Interwiring 73 Environmental Test Categories 84 ARINC 429 Label Definition 9APPENDIX1 Bibliography 12ARINC CHARACTERISTIC 731 Page 11.0 INTRODUCTION AND DESCRIPTION1.1 Purpose of this CharacteristicThis document sets forth the characte
16、ristics for a self-contained Electronic Chronometer specifically designed forinstallation in all types of commercial transport aircraft.The intent of this document is to provide general andspecific design guidance for the development andinstallation of a self-contained Electronic Chronometerprimaril
17、y for airline use. As such, this guidance will includethe details necessary to provide the desired operationalcapability and the standards necessary to achieveinterchangeability.Equipment manufacturers should note that this documentaims to encourage them to produce maintenance-free, high-performance
18、 devices. They are at liberty to accomplish thisobjective by means of design technique they consider to bethe most appropriate, as their airline customers areinterested primarily in the end result rather than the meansemployed to achieve it.1.2 Function of the EquipmentThe function of the self-conta
19、ined ElectronicChronometer is to provide the following indications to theflight crew: Time of day (UTC) (Universal Time Coordinate)Date of day (day, month, and year)Elapsed time (hours and minutes)Chronograph (minutes and seconds)COMMENTARYThe manner in which these indicators are displayeddoes not f
20、orm part of this Characteristic. See alsoCommentary under Section 3.5 regarding display ofyear during setting of the date of day. The equipment will also provide UTC, day, month, andyear data in digital form for use by other avionic systems.1.3 ReliabilityThe operational use of this system demands t
21、he utmostattention to the need for reliability of the self-containedElectronic Chronometer. Since clocks are included inaircraft minimum equipment lists, the importance ofequipment reliability cannot be over-emphasized.1.4 Unit DescriptionThe unit contains the time base, the display elements (UTCand
22、 date are provided depending on the setting by theoperator), and the necessary electronic circuitry needed toprovide digital coded output signals representing time anddate. The unit also provides the necessary controls forresetting the time of day, day, and month. Provisionsshould be made for remote
23、 control of the Chronographfunction.1.5 Interchangeability1.5.1 GeneralOne of the primary functions of an ARINC EquipmentCharacteristic is to designate, in addition to certainperformance parameters, the interchangeability desired ofaircraft equipment produced by various manufacturers.Manufacturers a
24、re referred to Section 1.6 of ARINC ReportNo. 414 for the airline industrys definitions of Terms andGeneral Requirements for interchangeability. As explainedin that Report, the degree of interchangeability considerednecessary and attainable for each particular equipment isspecified in the pertinent
25、ARINC Equipment Characteristic.Furthermore, “Generation Interchangeability” is desired bythe airline industry. “Generation Interchangeability”assures that future evolutionary equipment improvementsand the inclusion of additional functions in new equipmentsduring the next few years do not violate the
26、 interwiring andform factor standards set forth in this Document. Theprovisions to assure “Generation Interchangeability” are setforth as can best be predicted in various places throughoutthis Document to guide manufacturers in futuredevelopments.1.5.2 Interchangeability Desired for the ARINC 731Ele
27、ctronic ChronometerComplete plug-in interchangeability between units for thesame or different manufacturer is desired to meet the needsof ARINC 731 Characteristic.1.6 Regulatory ApprovalThe equipment should meet all applicable FAA and/or othergovernment regulatory requirements. This Characteristicdo
28、es not and cannot set forth the specific requirementswhich an equipment manufacturer must follow to be assuredof FAA approval under the TSO program.c-3ARINC CHARACTERISTIC 731 Page 22.0 INTERCHANGEABILITY STANDARDSIt is of prime importance that the Industry establish specificform factors, mounting p
29、rovisions, interwiring, input andoutput interfaces, and power supply standards for the self-contained Electronic Chronometer. These standards arenecessary to ensure continued independent design anddevelopment of both the equipment and the airframeinstallation.It should be noted that although this AR
30、INC Characteristicdoes not preclude the use of different form factors andinterwiring features, the practical problem of redesigningwhat will then be a standard aircraft installation toaccommodate some special system could very well makethe use of that other design prohibitively expensive for thecust
31、omer. Thus, manufacturers should recognize thepractical advantages of developing equipment inaccordance with the form factor, interwiring, and input andoutput interface standards of this Characteristic.2.1 Form Factors and ConnectorsThe unit should be contained in a 3 ATI case, dimensions asper ARIN
32、C Specification 408A. The case should notexceed 5 inch depth behind the panel (electrical connectornot included) and should employ a MIL C26482 connector(26 pins MS 3122E-16-26P or MS 3112E-16-26P) as setforth in ARINC 408A (Section 4.3). This connector shouldbe mounted in accordance with ARINC 408A
33、.COMMENTARYThis connector is used on the ARINC 585 ElectronicChronometer System. This should enable the airlinesto retrofit their fleets already equipped with ARINC585 ECS. They should note, however, that the 5 inchcase length may preclude the retrofit of the 731Chronometer into airplanes such as th
34、e B-727 and B-737 which can only accommodate a 4 inch caselength unit.2.2 CoolingThe Electronic Chronometer should be case cooled. Noprovisions should be made for forced air cooling. 2.3 Signal CharacteristicsThe signal characteristics necessary to insureinterchangeability are set forth in Section 4
35、.0 Digital SignalCharacteristics.2.4 Standard InterwiringThe interwiring which should be used in the “StandardInstallation” is set forth in Attachment 1 and the specialinterwiring notes listed in Attachment 2.2.5 Power CircuitryThe equipment should be designed to use 28 Vdc powerfrom the airplane ba
36、ttery hot bus as well as from any otheraircraft 28 Vdc bus. The aircraft power supplycharacteristics, utilization equipment design limitations, andgeneral guidance material are set forth in ARINC ReportNo. 413A, “Guidance for Aircraft Electrical PowerUtilization and Transient Protection.” Test condi
37、tions arecontained in RTCA DO-160 EUROCAE ED-14,“Environmental Conditions and Test Procedures forAirborne Electronic Electrical Equipment and Instruments.”c-2ARINC CHARACTERISTIC 731 Page 33.0 SYSTEM DESIGN CONSIDERATIONSThis section will describe the basic concepts underlying thedesign of the self-
38、contained Electronic Chronometer and itsrelationship to other avionic systems to which it may beconnected.3.1 Utilization Equipment OutputThe Electronic Chronometer will provide data output (UTCand date) on a digital bus in accordance with ARINC 429.3.2 Warning DevicesWarning flags or indicators, if
39、 provided at the customersoption should stay in view after a temporary hot battery buspower failure (loss of supply over 200 millisecond) until theUTC Time has been reset. All warning devices shouldderive their voltage from a source other than the lightingvoltage.3.3 Input PowerTwo separate 28 Vdc p
40、ower inputs are to be provided, onefor the time reference function and the other for the rest ofthe system except for indicator lighting.The time reference should function over a wide range ofinput voltages and be unaffected by voltage spikes causedby load switching external to the Electronic Chrono
41、meter. The load current should be kept to a minimum (less than25ma).The Electronic Chronometer should be designed to operatefrom a main power supply in accordance with ARINC413A.COMMENTARYIt is intended that the reference function will besupplied from the battery hot bus in order to preventloss of t
42、ime reference during main power shut down,though there will be no clock output in thatcircumstance; therefore, current drain on the batteryshould be minimized. The battery voltage rangeshould be assumed to be 16-40 Vdc.3.4 Lighting PowerThe self-contained Electronic Chronometer should utilizestandar
43、d cockpit lighting power of 5 Vac to be suppliedfrom the aircraft cockpit dimming bus. COMMENTARYThe circuitry for the remote control of the displaybrightness should be such that the wiring interface willsatisfy flight deck configurations for all airframes.Possible Displays:a. Magnetically positione
44、d wheelsb. Seven-bar incandescentc. LEDd. LCDe. OtherFrom past experience on displays b and c it has provednecessary to include a brightness control on each clockas well as a master remote brightness control to allowtrimming of the clock display to surrounding panelinstruments.3.5 Manual Setting (ti
45、me, date and day)Specific control means should be provided on theinstrument for setting of UTC, date and day functions.COMMENTARYThe setting of UTC should not affect the setting of thedate of day. In other words, setting of UTC and settingof date of day should be independent. The airlinesdesire to h
46、ave the bissextile (leap) year correctionaccomplished automatically by the ElectronicChronometer without need for operator intervention.This requires that the year be displayed during settingof the date of day, e.g. 80-06-18 for June 18, 1980.3.6 Chronograph ControlControl of the Chronograph functio
47、n is assured by amomentary switch located on the equipment. This switchaccomplishes the following sequential functions on thechronograph:a. Startb. Stopc. Reset to zeroProvision for remote control of the Chronograph functionshould be made utilizing pins on the electrical connector asshown in Attachm
48、ent 1, Standard Interwiring.3.7 Elapsed Time ControlThe control of the Elapsed Time is located on theequipment and accomplishes the RUN/STOP/RESETfunctions.The control device should enable the operator toaccumulate separate periods of time when selectingsuccessively the functions, RUN and STOP.No pr
49、ovision for remote control of the Elapsed Time ismade in this Characteristic.COMMENTARYThe Chronograph (CHRO) display should have priorityover the elapsed time (ET) display. If the CHRO andET functions are operating at the same time, the CHROfunction should be displayed and the ET functionshould update and be retained in memory. However,the independent CHRO and ET control switches shouldallow for starting, without disrupting the accuracy ofthe other function. In addition, the ET control switchshould permit momentary selection of the ET displaywhile the CHRO display is operating. T
