ASTM_F_2490_-_05_2013.pdf

Designation:F249005(Reapproved 2013)Standard Guide forAircraft Electrical Load and Power Source CapacityAnalysis1This standard is issued under the fixed designation F2490;the number immediately following the designation indicates the year oforiginal adoption or,in the case of revision,the year of last revision.A number in parentheses indicates the year of last reapproval.Asuperscript epsilon()indicates an editorial change since the last revision or reapproval.1.Scope1.1 This guide covers how to prepare an electrical loadanalysis(ELA)to meet FederalAviationAdministration(FAA)requirements.1.2 The values given in SI units are to be regarded as thestandard.1.3 This standard does not purport to address all of thesafety concerns,if any,associated with its use.It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2.Referenced Documents2.1 FAA Aeronautics and Space Airworthiness Standards:214 CFR 23.1309 Normal,Utility,Acrobatic,and CommuterCategory AirplanesEquipment,Systems,and Installa-tions14 CFR 23.1351 Normal,Utility,Acrobatic,and CommuterCategory AirplanesGeneral14 CFR 23.1353 Normal,Utility,Acrobatic,and CommuterCategory AirplanesStorage Battery Design and Instal-lation14 CFR 23.1419 Normal,Utility,Acrobatic,and CommuterCategory AirplanesIce Protection14 CFR 23.1529 Normal,Utility,Acrobatic,and CommuterCategory AirplanesInstructions for Continued Airwor-thiness14 CFR 91 General Operating and Flight Rules14 CFR 135.163 Operating Requirements:Commuter andOn Demand Operations and Rules Governing Persons onBoard Such AircraftEquipment Requirements:AircraftCarrying Passengers under IFR3.Terminology3.1 Definitions of Terms Specific to This Standard:3.1.1 abnormal electrical power operation(or abnormaloperation),noccurs when a malfunction or failure in theelectric system has taken place and the protective devices ofthe system are operating to remove the malfunction or failurefrom the remainder of the system before the limits of abnormaloperation are exceeded.3.1.1.1 DiscussionThe power source may operate in adegraded mode on a continuous basis when the power charac-teristics supplied to the using equipment exceed normal opera-tion limits but remain within the limits for abnormal operation.3.1.2 alternate source,nsecond power source that may beused instead of the normal source,usually on failure of thenormal source.3.1.2.1 DiscussionThe use of alternate sources creates anew load and power configuration and,therefore,a newelectrical system that may require separate source capacityanalysis.3.1.3 cruise,ncondition during which the aircraft is inlevel flight.3.1.4 electrical source,nelectrical equipment thatproduces,converts,or transforms electrical power.3.1.5 electrical system,nconsists of an electrical powersource,the electrical wiring interconnection system,and theelectrical load(s)connected to that system.3.1.6 emergency electrical power operation(or emergencyoperation),ncondition that occurs following a loss of allnormal electrical generating power sources or another malfunc-tion that results in operation on standby power(batteries orother emergency generating source such as an auxiliary powerunit(APU)or ram air turbine(RAT)only,or both).3.1.7 ground operation and loading,ntime spent in pre-paring the aircraft before the aircraft engine starts.3.1.7.1 DiscussionDuring this period,the APU,internalbatteries,or an external power source supplies electrical power.3.1.8 landing,ncondition starting with the operation ofnavigational and indication equipment specific to the landingapproach and following until the completion of the rollout.1This guide is under the jurisdiction of ASTM Committee F39 on AircraftSystems and is the direct responsibility of Subcommittee F39.01 on Design,Alteration,and Certification of Electrical Systems.Current edition approved July 1,2013.Published September 2013.Originallyapproved in 2005.Last previous edition approved in 2005 as F2490 051.DOI:10.1520/F2490-05R13.2Available from U.S.Government Printing Office Superintendent of Documents,732 N.Capitol St.,NW,Mail Stop:SDE,Washington,DC 20401.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 3.1.9 nominal rating,nthis rating of a unit power source isits nameplate rating and is usually a continuous duty rating forspecified operating conditions.3.1.10 normal ambient conditions,ntypical operatingconditions such as temperature and pressure as defined by themanufacturers technical documentation.3.1.11 normal electrical power operation(or normal opera-tion),nassumes that all the available electrical power systemis functioning correctly with no failures or within the MasterMinimum Equipment List(MMEL)limitations,if a MMELhas been approved(for example,direct current(DC)generators,transformer rectifier units,inverters,main batteries,APU,and so forth).3.1.12 normalsource,n