SAE AS 5562-2015 Ice and Rain Minimum Qualification Standards for Pitot and Pitot-static Probes.pdf

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4、side USA)Fax: 724-776-0790Email: CustomerServicesae.orgSAE WEB ADDRESS: http:/www.sae.orgSAE values your input. To provide feedbackon this Technical Report, please visithttp:/www.sae.org/technical/standards/AS5562AEROSPACESTANDARDAS5562Issued 2015-08Ice and Rain Minimum Qualification Standards for P

5、itot and Pitot-static ProbesRATIONALEThis standard provides a consistent means to evaluate electrically heated pitot and pitot-static probes for in-flight ice and rain conditions that may be experienced in service. This standard does not address other functions that are sometimes combined with pitot

6、 and static pressure measurements, such as aircraft AOA.1. SCOPEThis SAE Aerospace Standard (AS) establishes minimum ice and rain performance criteria for electrically-heated pitot and pitot-static probes intended for use on the following classes of fixed-wing aircraft and rotorcraft. The classes of

7、 fixed-wing aircraft are defined by aircraft flight envelopes and are shown in Figure 1. The flight envelopes generally fall into the classes as shown below:Class 1: Cruise altitude 23 000 feetClass 2: Cruise altitude 31 000 feetClass 3: Cruise altitude 42 000 feetClass 4: Cruise altitude 42 000 fee

8、tClass R: RotorcraftThe user of this standard must evaluate the aircraft level installation requirements for the probe against the class definition criteria to ensure adequate coverage for the application. It may be necessary to step up in class or modify the test conditions in order to meet the app

9、licable installation requirements. NOTE: Class 2 is divided into two subgroups identified as either Class 2a or Class 2b. Class 2a probe applications typically include aircraft that operate within the mid to lower end of the Class 2 altitude range and that only use probe output to display basic airs

10、peed and/or altitude. As such, Class 2a probes do not have to test ice crystals at an altitude-capable icing tunnel. Class 2b applications are for probe installations intended to serve a critical function and should be tested at an altitude-capable icing tunnel. Probes qualified to Class 2 of this s

11、tandard shall be identified as either Class 2a or Class 2b.In addition this performance standard applies only to the probe types listed below and is limited to only the performance of the probe itself as defined from the aerodynamic sensing aperture on the probe to the aircraft pneumatic interface c

12、onnection. Type I Pitot Pressure, Straight and L-ShapedType II Pitot and Static Pressures, Straight and L-ShapedNOTE: This specification, when used in conjunction with AS8006, provides a comprehensive design and test standard for the devices that fall within the scope of this document. NOTE: This do

13、cument is technically equivalent to EUROCAE ED-225, dated TBD.SAE INTERNATIONAL AS5562 Page 2 of 172. REFERENCES2.1 Applicable DocumentsThe following publications form a part of this document to the extent specified herein. The latest issue of SAE publications shall apply. The applicable issue of ot

14、her publications shall be the issue in effect on the date of the purchase order. In theevent of conflict between the text of this document and references cited herein, the text of this document takes precedence. Nothing in this document, however, supersedes applicable laws and regulations unless a s

15、pecific exemption has been obtained.2.1.1 SAE PublicationsAvailable from SAE International, 400 Commonwealth Drive, Warrendale, PA 15096-0001, Tel: 877-606-7323 (inside USA and Canada) or +1 724-776-4970 (outside USA), www.sae.org. ARP5624 Aircraft Inflight Icing TerminologyARP5905 Calibration and A

16、cceptance of Icing Wind TunnelsAS8006 Minimum Performance Standard for Pitot and Pitot-Static Tubes2.1.2 EUROCAE PublicationsAvailable from EUROCAE Secretariat, 102 rue Etienne Dolet, 92240 Malakoff, France, Tel: +33 1 40 92 79 30, . ED-225 MOPS Icing Conditions Test Requirements for Pitot and Pitot

17、-static Probes2.1.3 U.S. Government PublicationsCopies of these documents are available online at http:/quicksearch.dla.mil.MIL-HDBK-310 Global Climatic Data for Developing Military Products2.1.4 Code of Federal RegulationsAvailable from the United States Government Printing Office, 732 North Capito

18、l Street, NW, Washington, DC 20401, Tel: 202-512-1800, www.gpo.gov. Title 14 Code of Federal Regulations2.2 AbbreviationsAOA Angle of AttackCAS Calibrated AirspeedCM Continuous MaximumDP Delta PressuregGramKKiloIC Ice CrystalsSAE INTERNATIONAL AS5562 Page 3 of 17IM Intermittent MaximumISA Internatio

19、nal Standard AtmosphereIWC Ice Water ContentKTAS Knots True Airspeedkt KnotsLWC Liquid Water Contentm Metersmicrons Micrometers (common usage)MMD Median Mass Diameter (Ice Crystals) MP Mixed PhaseMVD Median Volumetric Diameter (Liquid) PST PistonRef Freestream Reference Test Condition SAT Static Air

20、 TemperatureSL Sea LevelSLD Supercooled Large DropsSLW Supercooled Liquid WaterTAS True AirspeedTAT Total Air TemperatureTBP TurbopropUUT Unit Under Test Micro Standard DeviationNOTE: Reference ARP5624 for a definition of each icing term. 3. GENERAL CONDITIONS 3.1 EnvironmentThis specification addre

21、sses the following environmental in-flight icing conditions: supercooled liquid water, ice crystals, and mixed phase. Additionally, the effects of heavy rain environments and the subsequent susceptibility to probe freezing after exposure to rain are also evaluated.SAE INTERNATIONAL AS5562 Page 4 of

22、17Supercooled large drops, such as freezing rain and freezing drizzle, are not directly evaluated in this specification. The conditions specified for SLW adequately address the effects of SLD and therefore, no direct SLD tests are required. This is based on the following: The characterizing paramete

23、rs of liquid water content and static air temperature associated with SLD conditions are covered by the SLW conditions. Analysis of the collection efficiency for liquid water associated with pitot and pitot-static probes indicates a value typically exceeding 90%. This implies the sensitivity of thes

24、e devices to variations in drop size is low and will be adequately addressed by the SLW conditions. Also, the LWC associated with the SLW test conditions substantially exceed SLD LWC levels found in service.3.1.1 Data Sources and Criteria for Environmental ConditionsSupercooled Liquid Water: Consist

25、s of water droplets derived from 14 CFR Part 25 Appendix C for both continuous maximum and intermittent maximum icing conditions. LWC is conservatively established by utilizing water contents associated with 15 micron droplets for the respective temperatures. A single droplet MVD of 20 microns is se

26、lected for evaluation based on the high probability of encountering droplets of this size in nature, and the ability of icing wind tunnelsto generate droplets of this size. The low LWC and higher altitude associated with the -40 C IM condition produces a less severe condition than the test condition

27、s specified by this standard. The altitudes and airspeeds for the liquid water conditions were determined by performing a critical point thermal analysis for the respective test condition temperature. Ice Crystals: Consists of ice water content derived from the application of the theoretical adiabat

28、ic total water content applied over an altitude range from sea level to 51 000 feet, and temperature range from -10 to -70 C. A median mass diameter range of 150 to 250 microns shall be acceptable and is based on the current knowledge of atmospheric ice crystal particle size.The altitudes associated

29、 with ice crystal conditions presented in this document consider in-service pitot and pitot-static probe events. The altitudes defined in this specification for ice crystal conditions are determined by the lower of the aircraft cruise altitude defined for that class or the ISA+30 C curve or the line

30、ar extension of the ISA+30 C lapse rate beyond 36 089 feet for the respective test condition temperature. The altitude-temperature envelope is shown in Figure 2. The airspeeds associated with ice crystal conditions are typical cruise speeds per the class definition, or those typical cruise speeds re

31、duced to maintain a TAT below freezing. Mixed Phase: Consists of the combination of SLW and IC icing conditions. The liquid phase is taken from the application of 14 CFR Part 25 Appendix C intermittent maximum icing conditions at the standard 2.6 nautical mile horizontal extent. The solid phase is d

32、erived by applying a distance scale factor for 2.6 nautical miles to the theoretical adiabatic maximum total water content as defined in14 CFR Part 25 Appendix D. This is done over an altitude range of sea level to that consistent with a static air temperature above -40 C, as -40 C constitutes the t

33、heoretical minimum temperature for the existence of supercooled liquid water. The temperature range considered shall be -10 to -40 C. The MVD and MMD shall be consistent with those used for SLW and IC icing conditions.The altitudes associated with the mixed phase test conditions are also based on in

34、-service event history, and are determined by the lower of the aircraft cruise altitude defined for that class or the ISA+20 C curve or the linear extension of the ISA+20 C lapse rate beyond 36 089 feet for the respective test condition temperature. The altitude-temperature envelope is shown in Figu

35、re 2. The airspeeds associated with ice crystal conditions are typical cruise speeds per the class definition, or those typical cruise speeds reduced to maintain a TAT below freezing. Rain: The values utilized are based on MIL-HDBK-310 for extreme precipitation rates. The temperature range evaluated

36、 is static air temperatures below 10 C, and drop sizes having an MVD in the range of 500 to 2000 microns. The broad range of allowable drop MVD acknowledges the difficulty of introducing large drops into some icing wind tunnels. Only one value within the specified range of temperature and MVD need b

37、e tested. Again, due to the insensitivity of these devices to drop size the significant parameters for rain testing are SAT, TAS, and LWC.Specific altitudes for the rain test conditions are not presented for these tests as they are primarily a test of the probe water management features. The altitud

38、es are representative of an all liquid water distribution for the extreme precipitation rates. The airspeeds are chosen to evaluate the probes at a high and low speed condition consistent with the test condition altitude requirements.SAE INTERNATIONAL AS5562 Page 5 of 173.2 Aircraft Class/Flight Par

39、ameter DiscussionThis standard defines five aircraft classes with the intent to specify the minimum icing test conditions appropriate to the flight envelope addressed by each class. In this fashion, test requirements can be better matched to the particular application. As with any minimum performanc

40、e standard, application specific requirements may exceed those defined in this specification; the user of this standard is cautioned to closely examine application specific requirements to verify the appropriateness of the test conditions presented in this standard. If necessary, the test conditions

41、 may be modified. However, parts identified as having met this standard must meet or exceed the requirements specified in this document. The fixed wing aircraft classes were determined by examining aircraft performance parameters (cruise altitude and airspeed) associated with fixed wing aircraft rep

42、resenting the spectrum of aircraft covered by this specification. The grouping of these aircraft by cruise altitude and Mach number is shown in Figure 1. As seen in Figure 1, the aircraft tend to group by the flight envelope defined by the aircraft classes presented in Section 1. Rotorcraft all gene

43、rally fall in the same area in terms of cruise altitude and airspeed and therefore did not require further class breakdown. Representative icing exposure flight and icing parameters (altitude, airspeed, IWC) were determined for each class of aircraft by assuming a flight profile that consists of a l

44、eg from takeoff and climb to cruise altitude, a leg at cruise altitude, and a leg from cruise altitude to a descent and landing. 3.3 Test Point Scaling When a particular freestream (reference) test condition cannot be achieved due to a test facility limitation, the following scaling methods shall be

45、 used to arrive at an achievable test condition. Other scaling methods may be acceptable so long as they are shown to be conservative for the respective test condition.3.3.1 Altitude LimitationDue to the potential safety exposure and in-service history, the ice crystal conditions specified for Class

46、 2b, 3, and 4 must be tested at the specified altitude. This is because as of the time of publication there is no acceptable method to scale the conditions for a non-altitude capable test facility. All other test conditions, including mixed phase, can be performed at a non-altitude capable facility

47、when appropriately scaled as described below. Experience has shown this to be conservative.NOTE: Ice crystal scaling methods continue to evolve. Suitable methods for scaling altitude may be developed in the future. These methods must be thoroughly validated.Thus, when testing at a non-altitude capab

48、le test facility the test shall be run matching each parameter, except altitude, to the greatest extent possible.3.3.2 Airspeed LimitationIf the airspeed is limited, the SAT shall be varied to maintain TAT identical to the reference condition:TATtest = TATrefLWC and/or IWC shall be varied to maintai

49、n the mass flux identical to the reference condition:LWCtest = LWCref * TASref / TAStestIWCtest = IWCref * TASref / TAStestSAE INTERNATIONAL AS5562 Page 6 of 173.3.3 Static Air Temperature LimitationIf the static air temperature is limited, the TAS shall be varied to maintain TAT identical to the reference condition:TATtest = TATrefLWC and/or IWC shall be varied to maintain the mass flux identical to th