1、 AEROSPACERECOMMENDEDPRACTICESubmitted for recognition as an American National StandardFLIGHT TEST PROCEDURES FOR STATIC PRESSURE SYSTEMSINSTALLED IN SUBSONIC TRANSPORT AIRCRAFTSAE Technical Standards Board Rules provide that: “This report is published by SAE to advance the state of technical and en
2、gineering sciences. Theuse of this report is entirely voluntary, and its applicability and suitability for any particular use, including any patent infringement arising therefrom, is thesole responsibility of the user.”SAE reviews each technical report at least every five years at which time it may
3、be reaffirmed, revised, or cancelled. SAE invites your writtencomments and suggestions.Copyright 1996 Society of Automotive Engineers, Inc.All rights reserved. Printed in U.S.A.Land Sea Air and SpaceFor Advancing MobilityThe Engineering SocietyINTERNATIONAL400 Commonwealth Drive, Warrendale, PA 1509
4、6-0001Issued 1971-07Revised 1996-09REV.ARP921 AFOREWORDChanges in the revision are format/editorial only.1. SCOPE:This SAE Aerospace Recommended Practice (ARP) covers the test procedures and equipment forperforming flight testing on pitot-static systems installed in subsonic transport type aircraft.
5、1.1 Purpose:The purpose of this document is to present recommendations for the flight testing of staticpressure systems as installed in subsonic transport type aircraft.2. REFERENCES:1. Federal Aviation Agency, Systems Research and Development Service Report, FlightCalibration of Aircraft Static Pre
6、ssure Systems, Report Number RD-66-3, dated February19662. Ikhtiari, Paul A. and Marth, Verlyn G.; Trailing Cone Static Pressure Measurement Device,pp. 93-94, Journal of Aircraft, Vol. 1, No. 2, March 19643. Shrager, Jack J.; Test of Trail Cone System to Calibrate Static Ports for BarometricAltimete
7、rs, FAA, NAFEC Report RD-64-156, December 19644. Shrager, Jack J.; Limited Survey of Commercial Jet Aircraft Altimeter System Error by Pacerwith Trailing Cone, FAA NAFEC Report RD-64-157, December 1964SAE ARP921 Revision A- 2 -2. (Continued):5. Air Transport Association of America Report, Recommenda
8、tions on Flush Static PortMaintenance, dated December 19636. Air Transport Association of America Report, Recommendations on Design of Pitot/StaticSystems for Transport Aircraft, dated January 19647. “An Investigation of the Effect of Random Fuselage Wall Irregularities on Flush StaticPressure Port
9、Calibrations”; Werner and Teigen, WADC Technical Report 57-365 (ASTIA130-805), April 19578. “Aircraft Skin Contour Measurements Adjacent to Flush Static Ports on Military TransportType Aircraft”; DeLeo, Hagen and Thompson, Rosemount Engineering Co., Technical Report4622B, April 19629. “Trailing Cone
10、 Systems Applications”; L. D. Crowley, Douglas Aircraft Co., TechnicalMemorandum TM-4158, dated August 196710. Anonymous: “Lo-Lag Trailing Cone System”; Technical Memorandum 4099, Douglas AircraftCompany, Long Beach, California, February 196611. DeLeo, R. V., Cannon, P. J., and Hagen, F. W.; “Evalua
11、tion of New Methods for FlightCalibration of Aircraft Instrument Systems; Part I, Analysis of Altimeter, Airspeed and Free-Air-Temperature Systems”; Report 6591, Rosemount Engineering Company, Minneapolis,Minnesota, June 1959. (Also issued as WADC Technical Report 59-295, Part I.)12. DeLeo, R. V. an
12、d Hagen, F. W.; “Evaluation of New Methods for Flight Evaluation of AircraftInstrument Systems; Part III, Development of Altimeter, Airspeed and Free-Air-TemperatureCalibration Systems”; Report 26123, Rosemount Engineering Company, Minneapolis,Minnesota, September 1961. (Also issued as WADC Technica
13、l Report 59-295, Part III.) (ASTIA 268780)13. DeLeo, R. V. and Hagen, F. W.; “Flight Calibration of Aircraft Static Pressure Systems”;Report 76431, Rosemount Engineering Company, Minneapolis, Minnesota, February 1966. (Also issued as FAA SRDS Report RD-66-3.)14. Gracey, W.; “Measurement of Static Pr
14、essure on Aircraft”; Report 1364, National AdvisoryCommittee for Aeronautics, Langley Aeronautical Laboratory, Langley Field, Virginia, 195815. Gracey, W., Jewel, J. W. Jr., and Carpenter, G. T.; “Measurement of the Errors of ServiceAltimeter Installations During Landing-Approach and Take-Off Operat
15、ions”; Technical NoteD-463, National Aeronautics and Space Administration, Langley Research Center, LangleyField, Virginia, November 196016. Gracey, W. and Stickle, J. W.; “Calibrations of Aircraft Static-Pressure Systems by Ground-Camera and Ground-Radar Methods”; Technical Note D-2012, National Ae
16、ronautics andSpace Administration, Langley Research Center, Hampton, Virginia, August 1963SAE ARP921 Revision A- 3 -2. (Continued):17. Mickle, D. A. and Soderquist, R. H.; “Trailing Cone Method of Measuring Static SourcePosition Error; Evaluation and Calibration Phase”; First Interim Report FT2123-5
17、6R-64, NavalAir Test Center, Patuxent River, Maryland, August 196418. Nairn, J. B.; “Results of Trailing Cone Tests on PAA Jet Aircraft”; Report SC-65-6, PanAmerican World Airways, Miami, Florida, September 196519. Russell, W. M.; “Trailing Cone Tests in Large Turbojet”; Technical Report RD-66-15,Na
18、vigation Development Division, Approach and Landing Branch, Federal Aviation Agency,Washington, DC, March 196620. Shrager, J. J.; “Calibrating Static Pressure Systems at Low Altitudes”; Report No. RD-64-37,Experimentation Division, National Aviation Facilities Experimental Center, Atlantic City, New
19、Jersey, March 1964. (AD 603205)21. Shrager, J. J.; “Test of Trail Cone System to Calibrate Static Ports for Barometric Altimeters”;Report No. RD-64-156, Experimentation Division, National Aviation Facilities ExperimentalCenter, Atlantic City, New Jersey, December 196422. Shrager, J. J.; “Limited Sur
20、vey of Commercial Jet Aircraft Altimeter System Position Error byPacer with Trailing Cone”; Report No. RD-64-157, Experimentation Division, National AviationFacilities Experimental Center, Atlantic City, New Jersey, December 196423. Silsby, N. S. and Stickle, J. W.; “Flight Calibrations of Fuselage
21、Static-Pressure-VentInstallations for Three Types of Transports”; Technical Note D-1356, National Aeronauticsand Space Administration, Langley Research Center, Hampton, Virginia, May 196224. Watson, E. T., Jr.; “Trailing Cone Reference System”; Report No. DEV-3674, Douglas AircraftCompany, Long Beac
22、h, California, November 19642.1 Regulator Documents:2.1.1 SAE Documents: The following SAE documents, of the issue in effect on the date ofapplication for certification, form a part of this Aerospace Recommended Practice to the extentnoted herein:ARP920 Design and Installation of Pitot-Static System
23、s for Transport AircraftARP975 Maintenance Procedures for Pitot-Static Systems for Transport AircraftSAE ARP921 Revision A- 4 -2.1.2 Federal Aviation Agency Documents: The following documents, of the issue in effect on date ofapplication for certification, form a part of this Aerospace Recommended P
24、ractice to the extentnoted herein.Federal Aviation Regulation - Air Worthiness Standards:Part 25 Transport Category AirplanesPart 43 Maintenance, Preventive Maintenance,Rebuilding and AlterationPart 91 General Operating and Flight RulesPart 121 Certification and Operation: AirCarriers and Commercial
25、 Operatorsof Large AircraftAdvisory Circular AC 43-203A Altimeter and Static System Testsand Inspections, effective June 6, 1967In the event of conflict between this document and the above documents, the regulatorydocuments shall apply.3. PITOT-STATIC SYSTEM GROUND TESTS:Prior to flight testing of a
26、ny pitot-static system, such system should have been tested in accordancewith the recommendations of ARP975.3.1 Prior to flight testing of any pitot-static system, at least one member of the flight crew shouldperform a visual inspection of the pitot-static system sensing orifice installations extern
27、al to theaircraft. All pitot-(static) tube protective covers shall have been removed. There shall be no tapeor other protective device covering flush static orifices. In addition, the aircraft should not beallowed to take off if there is any evidence of any deformity of the pitot-(static) tube or sk
28、insurrounding any flush static orifice. The static port installation and surrounding surfaceirregularities shall not exceed the tolerances as specified in ARP975.4. FLIGHT CALIBRATION AND TEST PROCEDURES:4.1 General:Several techniques have been developed for the calibration of aircraft pitot-static
29、systems. Theprimary objective of these test methods is to determine by flight test the static system (position)error and airspeed error over the performance envelope (speed, altitude, weight range andconfiguration) for which the aircraft is designed.SAE ARP921 Revision A- 5 -4.1 (Continued):The most
30、 important and widely used of these calibration techniques are described in subsequentparagraph. It is recognized that each technique is considered “standard” by some usingorganization (manufacturer or agency), and has certain advantages over other methods. However, in the interest of standardizatio
31、n, this ARP recommends and describes in detail onlyone technique, the trailing cone method.4.1.1 Camera Fly-Over Calibration Method: In this calibration method the height of the aircraft undertest is measured by photographing it as it flies directly overhead within an altitude range of100 to 500 ft
32、above the camera. Using the previously measured wing span of the aircraft andcalibrated focal length of the camera, the height of the aircraft above the camera can beaccurately determined. The atmospheric pressure is measured both at the camera site and inthe aircraft using calibrated pressure instr
33、uments. Temperature is also measured at thecamera site. Using the measured height, the true static pressure is computed for the fly-overelevation. The computed pressure is then compared with the actual pressure measured in theaircraft. The pressure difference resulting therefrom represents the stati
34、c pressure error of theaircraft at the particular Mach number, airspeed, weight, flap position and the angle of attackduring the fly-over.4.1.2 Tower Fly-By Calibration Method: In this method the height of the test aircraft is measured bytriangulation. The aircraft flies by a tower or tall building
35、at a height within a range between100 and 500 ft above the ground. The aircraft is sighted through a reference grid arrangementat or near the tower by a camera or eye piece located in the tower to determine elevation angle.The height of the aircraft above or below a fixed point in the tower is deter
36、mined bytriangulation. The horizontal distance of the aircraft from the tower must be accurately known. This is usually accomplished by having the aircraft fly down the centerline of a runway locatedin front of the tower.4.1.3 Pacer Aircraft Calibration Method: In this method the pressure altitude o
37、f the test aircraft ismeasured while flying in close formation with a calibrated aircraft or pacer. Both aircraft containcalibrated pressure instruments. While flying in close formation at the same altitude and aboutone wing span apart (between wing tips), pressure data are simultaneously recorded i
38、n eachaircraft. The pacer aircraft shall have a known pressure calibration as a function of airspeedand Mach number. Using this calibration and the difference in pressure recorded by the twoaircraft, the pressure error of the test aircraft may be computed.SAE ARP921 Revision A- 6 -4.1.4 Radar Tracki
39、ng Calibration Method: In this method the geometric altitude of the test aircraft isdetermined by ground based radar tracking equipment. The method is usually performed withthe test aircraft flying at altitudes of 5000 ft or above. This method requires the use ofcalibrated pressure instruments in th
40、e test aircraft or tracking of weather balloon to determineatmospheric pressure at altitudes above the radar location. The test aircraft must be previouslycalibrated in at least one condition (such as at a given indicated airspeed), and that this or othercalibrated conditions be utilized in the cali
41、bration of pressure versus elevation above the radar. After calibration of the space is performed by the test aircraft operating in the reference orpreviously calibrated mode or by the weather balloons, the aircraft is then flown through the testzone at various Mach numbers. As the position error of
42、 the aircraft changes with Mach numberand/or angle of attack, the aircraft will increase or decrease altitude in order to maintainindicated airspeed. Differences in altitude between the reference and test condition convertedto pressure, plus the position error at the reference condition then equals
43、the pressure error atthe test condition.4.1.5 Trailing Cone Calibration Method: The Trailing Cone Method is the most inexpensive andeasily used calibration method devised to date. In principle, the idea is to suspend a staticreference far enough behind an aircraft so that the ports are not affected
44、by the aerodynamicdisturbances of the airframe. A differential pressure gage is connected between the aircraftstatic ports and the trailing cone reference system. Using measurements taken from thesegages, the error in the static system may be determined. Using the trailing cone only oneaircraft, nam
45、ely the test aircraft, is involved. The combination aircraft/trailing cones can beflown at all altitudes and nearly all Mach numbers. Limitation and dependence upon groundbased facilities is also minimized. The use of a lightweight trailing cone appears to overcomeall serious deficiencies of other c
46、alibration methods and is herein recommended.The trailing cone calibration method exhibits very little or no static pressure errors. Theseerrors are a function of: (1) trailing cone configuration, (2) the distance aft of the aircraft atwhich the cone is trailed, and (3) the degree of air turbulence
47、at the trailing cone position. Itshould be emphasized that careful handling and deployment as well as proper positioningdistance behind the aircraft will virtually eliminate these small static errors.4.2 Detailed Calibration Procedure - Trailing Cone:4.2.1 General: A brief description of a trailing
48、cone assembly is given in 4.2.2.1 and References 2, 3and 4. Essentially, true static pressure is sensed by a set of holes placed around thecircumference of a hollow tube at a distance ahead of the drag (trailing) cone. The distance ofthe static holes behind the aircraft needed to obtain true static
49、pressure is dependent on thesize and type of aircraft and location of engines (i.e., aft mounted engine). Extension length isapproximately 100 to 130 ft for large turbo-jet aircraft and less for smaller aircraft. The distanceshould be determined for each aircraft configuration by flight test evaluation.The hollow tube transmits the true static pressure (Ps) to an accurate, small range differentialpressure gage and/or recorder which measures directly for static pressure position error(Pm- Ps); Pmis “measured” static pressure from the aircrafts static pressure source(s). Atypical flight p
