1、AEROSPACE RECOMMENDED PRACTICEARP416REV.AIssued 1963-02Reaffirmed 2008-02Revised 2001-10Directional Indicating System(Turbine Powered Subsonic Aircraft)FOREWORDChanges in this Revision are format/editorial only.1. SCOPE:This recommended practice covers the requirements for gyroscopically stabilized
2、Directional Indicating Systems, which will operate as a 1/hour latitude corrected, free directional gyro or as a slaved gyro, magnetic compass with 1/2 accuracy.1.1 Purpose:To recommend the essential minimum safe performance requirements for gyroscopically stabilized Directional Indicating System, p
3、rimarily for use with turbine powered subsonic transport aircraft, the operation of which may subject the instruments to the environmental conditions specified in paragraph 3.3.2. REFERENCES:There are no referenced publications specified herein.3. GENERAL REQUIREMENTS:3.1 Material and Workmanship:3.
4、1.1 Materials: Materials should be of a quality which experience and/or tests have demonstrated to be suitable and dependable for use in aircraft instruments.3.1.2 Workmanship: Workmanship should be consistent with high-grade aircraft instrument manufacturing practice.SAE Technical Standards Board R
5、ules 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 responsibility
6、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 a ret
7、rieval 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: Custome
8、rServicesae.org SAE WEB ADDRESS: http:/www.sae.org SAE ARP416 Revision A- 2 -3.2 Identification:The following information should be legibly and permanently marked on the instrument or nameplate attached thereto: (not necessarily in the order shown):a. Name of Instrumentb. ARP416Ac. Manufacturers par
9、t numberd. Manufacturers serial number or date of manufacturee. Manufacturers name and/or trade-markf. Rating (Electrical, etc.)g. Explosion Category3.3 Environmental Conditions:The following conditions have been established as design criteria only. Tests shall be conducted as specified in Sections
10、5, 6, and 7.3.3.1 Temperature: When installed in accordance with the instrument manufacturers instructions, the instruments should function over the range of ambient temperatures as listed in column A below and should not be adversely affected by exposure to the temperature shown in column B below.T
11、ABLE 13.3.2 Altitude: When installed in accordance with the instrument manufacturers instructions, the instruments should function from sea level up to the altitudes and temperatures listed below. Altitude pressures are per NACA Report 1235. The instrument should not be adversely affected following
12、exposure to extremes in ambient pressure of 50 and 3 inches Hg absolute respectively.TABLE 2SAE ARP416 Revision A- 3 -3.3.3 Vibration: When installed in accordance with the instrument manufacturers instructions, the instrument should function and should not be adversely affected when subject to vibr
13、ations of the following characteristics:TABLE 33.3.4 Humidity: The instrument should function and should not be adversely affected following exposure to any relative humidity in the range from 0 to 95% at a temperature of approximately 70 C.3.4 Explosion Category:All instrument components located in
14、 the uninhabited areas of non-pressurized aircraft or in the non-pressurized areas of pressurized aircraft should not cause an explosion when operated in an explosive atmosphere. Each component located in such an area should meet the requirements of one of the explosion proof categories given below.
15、If it is intended that a component which might be an ignition source will be located in an area where combustible fluid or vapor may occur in normal operation, such as a fuel tank, it should be designed to meet the requirements of Category II, below. If the intended location is an area where combust
16、ible fluid or vapor may occur only as a result of abnormal conditions, such as leakage of a fuel line, it should be designed to meet the requirements of Category I, below.SAE ARP416 Revision A- 4 -TABLE 43.5 Fire Hazard:The instrument should be so designed to safeguard against hazards to the aircraf
17、t in the event of malfunction or failure, and the maximum operating temperature of surfaces of any instrument component contacted by combustible fuel or vapor should not exceed 200 C due to self-heating.3.6 Radio Interference:The instrument should not be the source of objectionable interference unde
18、r operating conditions at any frequencies used in aircraft, either by radiation or feedback in the electronic equipment installed in the same aircraft as the instrument.3.7 Magnetic Effect:The magnetic effect of the instruments should not adversely affect the performance of other instruments install
19、ed in the same aircraft.3.8 Decompression:When installed in accordance with the instrument manufacturers instructions, the instrument shall function and not be adversely affected following exposure to a pressure decrease from 22 to 2 inches of mercury in 2 seconds.SAE ARP416 Revision A- 5 -4. DETAIL
20、 REQUIREMENTS:4.1 Display Markings:4.1.1 Finish: Unless otherwise specified by the user, matte white material should be applied to all graduations, numerals, and indication means.Non-functional surfaces and markings should be durable dull black.4.1.2 Graduations: The graduations should be arranged t
21、o provide the maximum of readability consistent with the accuracy of the instrument.4.1.3 Numerals: The display should include sufficient numerals to permit quick and positive identification of each graduation. Numerals should distinctly indicate the graduation to which each applies.4.1.4 Instrument
22、 Title: The instrument title, when used, should be of the same approximate size but no larger than the numerals. The title may be of the same finish as the numerals. The units of measure should appear on the dial in lettering noticeably smaller than either the numerals or title.4.1.5 Visibility: The
23、 indicating means and all markings should be visible from any point within the frustum of a cone the side of which makes an angle of at least 30 degrees with the perpendicular to the dial and the small diameter of which is the aperture of the instrument case. The distance between the dial and the co
24、ver glass should be a practical minimum.4.2 Power Variation:The instrument should properly function with plus or minus 15 percent variation in D.C. voltageand/or plus or minus 10 percent variation in A.C. voltage and plus or minus 5 percent variation in frequency.4.3 Power Malfunction Indication:Mea
25、ns should be incorporated in the instrument to indicate when adequate power (voltage and/or current) is not being made available to all phases required for the proper operation of the instrument. The indicating means should indicate a failure or a malfunction in a positive manner.4.4 Hermetic Sealin
26、g:When hermetically sealed, the case should be filled with an inert gas, free of dust particles, and sufficiently dry so that fogging of the indicator glass does not occur during the low temperature and fogging tests of this Aerospace Standard.4.5 Synchro Requirements:The synchro requirements should
27、 be in accordance with the conditions specified in ARP461.SAE ARP416 Revision A- 6 -4.6 Gyro Caging Provisions:Unless the gyro assembly can be made to accommodate extreme maneuvers of the aircraft without tumbling, means should be provided for caging and/or releveling the gyro. Means should be provi
28、ded to indicate when the gyro is caged, except when it is not possible to leave the gyro in caged condition.4.7 Modes of Operation:A means should be provided to select the mode of operation of the directional indicating system. In magnetic mode, the system should operate as a magnetic compass and sy
29、nchronize with the earths magnetic field. In the Directional Gyro mode, the system should operate as a latitude corrected directional gyro.4.8 Operating Limits:The instrument should indicate heading throughout the 360 degree scale range. During dives, climbs or banks up to at least 60 degrees displa
30、cement from level flight, the instrument should remain functional; however, the heading error involved through the gimbal system need not be corrected. The system should be provided with means to permit deactivating the slaving means during maneuvers.4.9 Synchronizing Provisions:Initial automatic or
31、 manual means should be provided to bring the indicating heading into alignment with the magnetic heading. Thereafter, in the magnetic mode, the indicated heading should be automatically and continuously aligned with magnetic heading within 0.5 degree. An indication of alignment should also be provi
32、ded.4.10 Directional Gyro Transmitting Synchros:At least one synchro transmitter, electrically isolated from the compass system, should be provided on the output or azimuth axis of the gyro to transmit signals proportional to the position of the gyro. This synchro should comply with ARINC, Index and
33、 rotation reference standards. The output impedance should be 100 ohms or less and have an output voltage, at maximum coupling, of 11.8 volts line-to-line open circuit.4.11 Data Transmitters:A minimum of two synchro heading data transmitters, whose rotors are postitioned by the heading output shaft
34、of the system, should be provided for the electrical transmission of heading reference to auxiliary equipment. All connections to rotors and stators should be brought out to separate pins in the electrical connector. These synchros should comply with ARINC Index and rotation reference standards. Eac
35、h synchro should have an output impedance of 30 ohms or less and an output voltage, at maximum coupling, of 11.8 volts line-to-line open circuit.SAE ARP416 Revision A- 7 -4.12 Latitude Correction:A manually set control should be provided to correct the system, in the compass and DG modes of operatio
36、n (preferably combined with the mode selection means), for the apparent drift of the gyro due to earths rotation. The correction should be at a rate equal to the product of 15 per hour multiplied by the sine of the local latitude. Provision should be made for both northern and southern hemisphere co
37、rrection. A means should be provided to prevent accidental application of the wrong hemisphere correction. The correction scale should be graduated in degrees per hour with 2 increments and major divisions and numerals every 5 or degrees of latitude with 5 increments and major divisions and numerals
38、 every 10.4.13 Power Indication:Means shall be incorporated in the instrument to indicate when adequate power (voltage and/or current) is not being made available to all phases required for the proper operation of the instrument. The indicating means shall indicate a failure or malfunction in a posi
39、tive manner.5. TEST CONDITIONS:5.1 Atmospheric Conditions:Unless otherwise specified, all tests required by this specification should be made at an atmospheric pressure of approximately 29.92 inches of mercury and at an ambient temperature of approximately 25 C, and at a relative humidity of not gre
40、ater than 85%. When tests are made with the atmospheric pressure or the temperature substantially different from these values, allowance should be made for the variations from the specified conditions.5.2 Vibration to Minimize Friction (Turbine Powered Subsonic Aircraft):Unless otherwise specified h
41、erein, all tests for performance may be conducted with the instrument subjected to a vibration of 0.001 inch double amplitude at a frequency of 10 to 60 cycles per second. The term double amplitude, as used herein, indicates the total displacement from positive maximum to negative maximum.5.3 Vibrat
42、ion Equipment:Vibration equipment should be such as to allow vibration to be applied along each of three mutually perpendicular axes of the instrument at frequencies and amplitudes consistent with the requirements of paragraph 3.3.3.5.4 Power Conditions:Unless otherwise specified, all tests should b
43、e conducted at the power rating recommended by the manufacturer.SAE ARP416 Revision A- 8 -5.5 Position:Unless otherwise specified, all tests should be made with the instrument (indicators, amplifiers, transmitters, etc.) mounted in normal operating position.5.6 Magnetic Field Strength:Unless otherwi
44、se specified, all tests required by this specification should be made with a horizontal field strength of approximately 0.18 gauss and a vertical field strength of approximately 0.54 gauss in the direction normal in the northern hemisphere. When tests are made with field strength values substantiall
45、y different from these values, allowance should be made for variations from the specified tolerances.6. INDIVIDUAL PERFORMANCE REQUIREMENTS:All instruments or all components of the system should be subjected to whatever tests the manufacturer deems necessary to demonstrate specific compliance with t
46、his recommended practice, including the following requirements where applicable.6.1 Starting:The time for the compass system to attain full operating status should not exceed three minutes. The gyro should have attained 85% of full speed.6.2 Scale Error:A magnetic transmitter with known error should
47、 be mounted on a suitable turntable in an area having magnetic quality which will permit the performance of this test. The compass should be connected and set into operation as a magnetic compass and synchronized on magnetic north. The transmitter should be rotated in 15 increments through 360 clock
48、wise and the system manually set to a synchronized null on each heading. A unit containing a synchro of known calibration mounted in an accurate positioning device and a null reading meter, or their equivalents, should be electrically connected to the data transmitter for accurate determination of c
49、ompass heading. These readings should be recorded for each position of the magnetic transmitter. The test should be repeated for each successive 15 heading, from 0, with a counterclockwise rotation of the magnetic transmitter. The deviation, thus determined, should be added algebraically and the result divided by the number of readings. This result should be the index error and should not exceed plus or minus 1/4. The individual reading should not differ from the correct heading, less the index error by more than 0.5. The differenc
