1、AEROSPACESTANDARDCOMPASS, MAGNETIC, NON-STABILIZED TYPE(FOR TURBINE-POWERED, SUBSONIC AIRCRAFT)Issued 1964-04Revised 1996-09REV. AS443 AFOREWORDChanges in the revision are format/editorial only.1. SCOPE:This SAE Aerospace Standard (AS) covers a direct reading magnetic compass.1.1 Purpose:This docume
2、nt establishes the essential minimum safe-performance standards for non-stabilizedmagnetic direction instruments, primarily for use with turbine-powered, subsonic, transport aircraftthat may subject the instruments to the environmental conditions specified in paragraph 3.3.2. APPLICABLE DOCUMENTS:Th
3、e following publications form a part of this document to the extent specified herein. The latestissue of SAE publications shall apply. The applicable issue of other publications shall be the issuein effect on the date of the purchase order. In the event of conflict between the text of thisdocument a
4、nd references cited herein, the text of this document takes precedence. Nothing in thisdocument, however, supersedes applicable laws and regulations unless a specific exemption hasbeen obtained.2.1 NTIS Publications:Available from NTIS, Springfield, VA 22161.NACA Report 1235SAE Technical Standards B
5、oard Rules provide that: “This report is published by SAE to advance the state of technical and engineering sciences. The use of this report is entirely voluntary, and its applicability and suitability for any particular use, including any patent infringement arising therefrom, is the sole responsib
6、ility of the user.” SAE reviews each technical report at least every five years at which time it may be reaffirmed, revised, or cancelled. SAE invites your written comments and suggestions. Copyright 2008 SAE International All rights reserved. No part of this publication may be reproduced, stored in
7、 a retrieval system or transmitted, in any form or by any means, electronic, mechanical, photocopying, recording, or otherwise, without the prior written permission of SAE. TO PLACE A DOCUMENT ORDER: Tel: 877-606-7323 (inside USA and Canada) Tel: 724-776-4970 (outside USA) Fax: 724-776-0790 Email: C
8、ustomerServicesae.org SAE WEB ADDRESS: http:/www.sae.orgReaffirmed 2008-02SAE AS443 Revision A- 2 -3. GENERAL REQUIREMENTS:3.1 Materials and Workmanship:3.1.1 Materials: Materials shall be of a quality which experience and/or tests have demonstrated tobe suitable and dependable for use in aircraft i
9、nstruments.3.1.2 Workmanship: Workmanship shall be consistent with high-grade aircraft instrumentmanufacturing practice.3.2 Identification:The following information shall be marked legibly and permanently on the instrument or attachedthereto:a. Name of instrumentb. SAE AS443Ac. Manufacturers part nu
10、mberd. Manufacturers serial number or date of manufacturee. Manufacturers name and/or trademark3.3 Environmental Conditions:The following conditions have been established as minimum design requirements. Tests shall beconducted as specified in Sections 5, 6, and 7.3.3.1 Temperature: When installed in
11、 accordance with the instrument manufacturers instructions,the instrument shall function over the range of ambient temperature shown in Column A belowand shall not be affected adversely by exposure to the range of temperature shown in ColumnB below.TABLE 1Instrument Location A BPressurized areas -30
12、 to 70 C -65 to 70 CSAE AS443 Revision A- 3 -3.3.2 Altitude: When installed in accordance with the instrument manufacturers instructions, theinstruments shall function from sea level conditions up to the altitudes and temperatures listedbelow. (Altitude pressure values are per NACA Report 1235.) The
13、 instrument shall not beaffected adversely following exposure to extremes in ambient pressure of 50 to 3 inches Hgabsolute, respectively:TABLE 2Instrument Location Altitude TemperaturePressurized areas 15,000 feet 50 C3.3.3 Vibration: When installed in accordance with the instrument manufacturers in
14、structions, theinstrument shall function and shall not be affected adversely when subjected to vibrationshaving the following characteristics:TABLE 3Maximum Double MaximumFrequency Amplitude AccelerationInstrument Location (cps) (inches) (g)Instrument Panel 5-30 0.020 -30-1000 0.253.3.4 Humidity: Th
15、e instrument shall function and shall not be affected adversely by exposure to anyrelative humidity in the 0 to 95% range at a temperature of approximately 70 C.4. DETAIL REQUIREMENTS:4.1 Display Marking:4.1.1 Finish: Unless specified otherwise by the user, matte white material shall be applied to a
16、llgraduations, numerals, and indicating means. Non-functional surfaces and markings shall bedurable dull black.4.1.2 Indicating Method: The method of indication shall employ a horizontal compass card with fixedlubbers line. Graduations move to the right for right turns.4.1.3 Graduations: The instrum
17、ent shall be provided with graduations at intervals not to exceed5 degrees, with major graduations every 10 degrees and with numerical markings at intervalsnot greater than 30 degrees. The 0, 90, 180, and 270-degree cardinal headings may bemarked N, E, S, and W, respectively; or in numerical marking
18、 the last digit (0) may be omitted.SAE AS443 Revision A- 4 -4.1.4 Visibility: Index and dial markings shall be visible from any point within the frustum of a conethe side of which makes an angle of 30 degrees with the perpendicular to the dial, and thesmall diameter of which is the aperture of the i
19、nstrument case. At least two numerals shall bevisible simultaneously.4.1.5 Operating Limits: During straight flight the instrument shall indicate magnetic headingsthroughout the 360-degree scale range during dives, climbs, or banks up to at least 20 degreesdisplacement from level flight.4.2 Compensa
20、tion Provisions:Means shall be provided for compensating for semi-circular deviation. Compensating effect shallbe between 20 and 40 degrees in each direction for each axis when adjusted for maximum effect.5. TEST CONDITIONS:5.1 Atmospheric Conditions:Unless specified otherwise, all tests required by
21、 this Aerospace Standard shall be made at anatmospheric pressure of approximately 29.92 inches Hg absolute, an ambient temperature ofapproximately 25 C and a relative humidity not exceeding 85%. When tests are conducted withthe atmospheric pressure or temperature differing substantially from these v
22、alues, allowanceshall be made for the variation from the specified conditions.5.2 Vibration to Minimize Friction:Unless specified otherwise, all tests for performance may be conducted while the instrument issubjected to a vibration of 0.001 to 0.005 inch double amplitude at a frequency of 10 to 60 c
23、yclesper second. The term double amplitude, as used herein, indicates the total displacement frompositive maximum to negative maximum.5.3 Vibration Equipment:Vibration equipment shall be such as to allow vibration to be applied along each of three mutuallyperpendicular axes of the instrument at freq
24、uencies and amplitudes consistent with requirementsof 3.3.3.5.4 Position:Unless specified otherwise, all tests shall be conducted while the instrument is in its normaloperating position.SAE AS443 Revision A- 5 -5.5 Magnetic Field Strength:Unless specified otherwise, all tests required by this Aerosp
25、ace Standard shall be made with ahorizontal field strength of approximately 0.18 gauss and a vertical field strength of approximately0.54 gauss, in the direction normal in the northern hemisphere. When tests are made with fieldvalues substantially different from these values, allowance shall be made
26、 for variations from thespecified tolerances.5.6 Compensators:Unless specified otherwise, all tests shall be made with magnetic compensators removed oradjusted to neutral positions.6. INDIVIDUAL PERFORMANCE REQUIREMENTS:All instruments shall be subjected to tests by the instrument manufacturer to de
27、monstrate specificcompliance with this Aerospace Standard, including the following requirements where applicable.6.1 Leakage:Liquid-filled instruments shall not show evidence of leakage after having been placed in a bell jarand subjected to a pressure equivalent to 50,000 feet, standard altitude, fo
28、r a period of 1 hour.6.2 Scale Error:When the instrument is placed on magnetic headings at 30-degree intervals starting from North,the indicated headings shall correspond to actual magnetic headings within 4 degrees.6.3 Friction:The card shall be deflected 5 degrees from its equilibrium position, re
29、leased, allowed to come torest, and read. The test shall be repeated deflecting the card 5 degrees in the opposite direction.Without vibration or tapping the difference between the two readings at rest shall not exceed2 degrees.6.4 Damping:When the instrument has been deflected 30 degrees, first to
30、the right and then to the left from itsequilibrium position, the time required for the indicated heading to pass through the 25-degreeangle toward the original heading shall not exceed 5.0 seconds or be less than 1.0 second. Themaximum overswing past the original indicated heading shall not exceed 1
31、5 degrees.SAE AS443 Revision A- 6 -6.5 Heeling Error:When the instrument is tilted 20 degrees from the normal level position, the magnetic elementshall be free to rotate through 360 degrees. When the instrument is tilted 10 degrees, theindicated heading shall not differ from the indicated heading wi
32、th the instrument unit in normallevel position by more than 4 degrees. The instrument compass card shall be visible as specifiedin 4.1.4.6.6 Swirl:When the instrument is rotated in azimuth in its normal upright position, at a rate of 30 degreesper second through 360 degrees, stopping successively at
33、 each cardinal point, the overswing ofthe compass card at each of these points shall not exceed 6 degrees.6.7 Compensation:With the instrument unit on N heading and the compensator adjusted for minimum effect, thescale error with the compensator shall not differ from the scale error without the comp
34、ensator bymore than 2 degrees. The maximum adjustable compensation effect shall be between 20 and 40degrees in each direction for each axis. When the instrument is placed on any cardinal headingand the opposite axis compensator is adjusted for maximum effect, the indicated reading shallnot change mo
35、re than 2 degrees.6.8 Dielectric:Each instrument shall be tested by the method of inspection listed in 6.8.1 and 6.8.2.6.8.1 Insulation Resistance: The insulation resistance measured at 200 volts DC for 5 secondsbetween all electrical circuits connected together and the metallic case shall not be le
36、ss than5 megohms. Insulation resistance measurements shall not be made on circuits where thepotential will appear across elements such as windings, resistors, capacitors, etc., since thismeasurement is intended only to determine adequacy of insulation.6.8.2 Overpotential Tests: The lighted instrumen
37、t shall not be damaged by the application of a testpotential between electrical circuits and between electrical circuits and the metallic case. Thetest potential shall be a sinusoidal voltage of a commercial frequency with an rms value of fivetimes the maximum circuit voltage, except where the condi
38、tion specified in 6.8.2.1 applies. Thepotential shall start from zero and be increased at a uniform rate to its test value. It shall bemaintained at this value for 5 seconds and then reduced at a uniform rate to zero. Since thesetests are intended to insure proper electrical isolation of the circuit
39、 components in question,these tests shall not be applied to circuits where the potential will appear across elements suchas windings, resistors, capacitors, bulbs, etc.SAE AS443 Revision A- 7 -6.8.2.1 Circuits that operate at potentials below 15 volts are not to be subjected to over-potentialtests.7
40、. QUALIFICATION TESTS:As many instruments as the manufacturer deems necessary to demonstrate compliance with therequirements of this section shall be tested in accordance with his recommendations.7.1 Temperature Characteristics:7.1.1 Low Temperature Operation: The instrument shall be subjected to th
41、e applicable low ambienttemperature listed in Column A (3.3.1). After exposure to this temperature for 5 hoursperformance as specified in 6.2 shall be obtained immediately using the magnetic field strengthspecified in 5.5 (except the field strength tolerance shall be 20%).7.1.2 High Temperature Oper
42、ation: The requirements of 7.1.1 shall apply except that the exposuretemperature shall be the applicable high-ambient temperature listed in Column A of 3.3.1.7.1.3 Extreme Temperature Exposure: The instrument shall be exposed to the applicable low andhigh temperatures listed in Column B of 3.3.1 for
43、 a period of 24 hours at each extremetemperature, without operating. After a period of 3 hours at room temperature, the instrumentshall meet the requirements of 6.1 and 6.2 at room temperature. There shall be no evidence ofdamage as a result of exposure to the extreme temperatures specified.7.2 Vibr
44、ation:7.2.1 Resonance: The instrument, while operating, shall be subjected to a resonant frequencysurvey of the appropriate range specified in 3.3.3 in order to determine whether any resonantfrequencies of the parts exist. The amplitude used may be any convenient value that does notexceed the maximu
45、m double amplitude and the maximum acceleration specified in 3.3.3. Theinstrument shall then be subjected to vibration at the appropriate maximum double amplitude ormaximum acceleration specified in 3.3.3 at the resonant frequency for a period of 1 hour alongeach axis. If more than one resonant freq
46、uency is encountered with vibration applied along anyone axis, a test period may be accomplished at the most severe resonance, or the period maybe divided among the resonant frequencies, whichever shall be considered more likely toproduce failure. The test period shall not be less than 1/2 hour at a
47、ny resonant mode. Whenresonant frequencies are not apparent within the specified frequency range, the instrumentshall be vibrated for 2 hours along each axis in accordance with the vibration requirementsschedule (3.3.3) at the maximum double amplitude and the frequency to provide the maximumaccelera
48、tion.SAE AS443 Revision A- 8 -7.2.2 Cycling: The instrument while operating shall be tested while the frequency is cycled betweenthe limits specified in 3.3.3 in 15-minute cycles for a period of 1 hour along each axis at theapplied double amplitude specified in 3.3.3, or the acceleration specified i
49、n 3.3.3, whichever isthe limited value. After the completion of this vibration test, no damage shall be evident and theinstrument shall meet the requirements of Section 6 (except dielectric requirements of 6.8).7.3 Humidity: The instrument shall be mounted in a chamber maintained at a temperature of70 2 C and a relative humidity of 95 5% for a period of 6 hours. After this period, the heatshall be shut off and the instrument allowed to cool for a period of 18 hours in an atmosphere inwhich the humidity rises to 100% as the temperature decreases to not less
