1、SAE AS*:802L BL 83573LtO 003L1LLt5 Lt M however, the heading error involved through the gimbal system need not be corrected. 3.10 Dial Markings: 3.10.1 Graduations: The indicators shall be provided with degree graduations at intervals not to exceed five (5) degrees, with major graduations every ten
2、(10) degrees and with numerals at intervals not greater than 30 degrees, except that the O, 90, 180, and 270 degrees positions may be marked N, E, S, and W, respectively. 3.10.2 Visibility: Index and dial markings shall be visible from any point within the upper half of a frustum of a cone, the side
3、 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. At least two numerals shall be simultaneously visible. 3,11 Caging Provisions: Unless the gyro assembly has restricted freedom of operation in th
4、e pitch and roll axes, a means shall be provided for caging and/or releveling the gyro. shall be provided to indicate when the gyro is caged, except when it is not possible to leave the gyro in the caged condition, A means 3.12 Course S.etting Provisions: A means shall be provided for manually setti
5、ng the directional in- dicator to any heading desired. Copyright SAE International Provided by IHS under license with SAENot for ResaleNo reproduction or networking permitted without license from IHS-,-SAE AS*021 81 M 83573L)O 003Lt147 8 U -3- I AS SO21 4. MINIMUM PERFORMANCE REQUIREMENTS UNDER STAN
6、DARD TEST CONDITIONS : 4.1 4.2 4.3 Starting: normal power is applied for both air and electric operated instruments. 50 percent of rated vacuum or pressure for air operated instruments and 80 percent of rated voltage for eIectrically operated instruments, the gyro rotor shail start and continue to r
7、otate. If the instrument incorporates a gyro speed monitoring device which provides a positive indicatioi when the gyro speed is below that necessary to meet instrument performance, the starting time may exceed three minutes, but shall not be greater than five minutes. Rated instrument performance r
8、otor speed shall be achieved wit4iin three minutes after By application of Roll, Pitch and Yaw: oscillate in roll, pitch and yaw, with a total amplitude of 3 degrees about each axis, at a frequency of 5 to 7 oscillations per minute while reversing the direction of rotation every 6 revolutions. the d
9、ial reading shall be noted. movement. At the end of a ten minute period the oscillation shall be stopped, the platform realigned to its starting position, and the instrument dial reading noted. of the dial in either direction during the ten minute test period shall not exceed 4 degrees. This test sh
10、all be run four times with the instrument case rotated 90 with respect to the outer gimbal between each test. The instrument shall be mounted on a test .platform which is adjusted to With the platform level, and the gyro operating at equilibrium speed and uncaged The platform shall then be started i
11、n its roll, pitch and yaw The amount of drift Heading Stablity: the vertical and the reading noted. The turn table shall be rotated one complete revolution about its axis at 360 (230) degrees per minute and the drift of the dial shall not exceed two degrees. The instrument shall be mounted on a turn
12、 table, tilted 54 (21) degrees from The test shall be repeated rotating the turn table in the opposite direction. 5. MINIMUM PERFORMANCE REQUIREMENTS UNDER ENVIRONMENTAL CONDITIONS : Unless otherwise specified herein , the procedures applicable to a determination of the performance of directional in
13、struments under environmental conditions are set forth in Radio Technical Com- mission for Aeronautics (RTCA) mcument No. DO- 160, entitled “Environmental Conditions and Test Procedures for Airborne Electronic/Electrical Equipment. and hstrumentstt, dated February 1975. Performance tests specified a
14、fter subjection to test environments may be made after exposure to several environmental conditions. The order of tests shail be in accordance with paragraph 3.2, page 4, of DO-160. for use in determining the performance of directional instruments under standard and extreme environmental conditions.
15、 Alternate approved test procedures that provide equivalent results may be used. Will comply with the requirements of this paragraph, shall be tested in accordance with the manufacturers recommendations. The test .procedures specified or referenced are satisfactory As many instruments as deemed nece
16、ssary to demonstrate that all instruments 5.1 Performance Standard for Use During Environmental Tests: shall be used when performance testing during an environmental test is required: The foilowing performance standard (a) There shall be no more than five degrees drift in either direction during a t
17、en minute . period. Roll, pitch, and yaw motion is not required for this test. 5.2 Temperature - Altitude - Humidity : (a) Low-Temperature - The instrument shall be subjected to the tests of DO-160, para- graph 4.4. During the test, the instrument shall operate electrically and mechanically and the
18、requirements of paragraph 5.1 of this Standard shall be met. test, the requirements of paragraph 4.0 of this Standard shall be met at standard conditions. Foilowing the 1 Copyright SAE International Provided by IHS under license with SAENot for ResaleNo reproduction or networking permitted without l
19、icense from IHS-,-SAE AS*B02L BI = 8357340 0034L48 T = I AS 8021 I -4- I (b) High Temperature - The instrument shall be subjected to the tests of DO-160, paragraph 4.5.1 and 4.5.2. operateelectrically and mechanically and there shall be no evidence of materials such as potting and sealing compounds
20、exuding or dripping from the instrument, When subjected to the tests of paragraph 4.5.2, the instrument shall operate electrically and mechanically and the requirements of paragraph 5.1 of this Standard shaU be met. Following the test, the requirements of paragarph 4.0 of this Standardshali be met a
21、t standard conditions. During the test, paragraph 4.5.1, the instrument shall (c) Altitude - The instrument shall be subjected to the tests of DO-160, paragraphs 4.6.1, 4.6.2, and 4.6.3. During the test, paragraph 4.6.1, the instrument shaU operate electrically and mechanically and the requirements
22、of paragraph 5.1 of this Standard shall be met. After being subjected to the tests of paragraph 4.6.2, the requirements of paragraph 4. O of this Standard shall be met at standard conditions, and after being subjected to the tests of paragraph 4.6.3, the requirements of paragraph 4.0 shall be met. (
23、d) Humidity - The instrument shall be subjected to the tests of DO-160, paragraph 6.0. After the instrument is subjected to the appropriate tests of paragraph 6.0, it shall meet the requirements of paragraph 4.0 of this Standard at standard conditions. 5.3 5.4 5.5 Shock: The instrument shall be subj
24、ected to the tests of DO-160, paragraphs 7.1 and 7.2. (a) After the instrument is subjected to the tests of paragraph 7.1, it shall meet the requirements of paragraph 4. O of this Standard under standard conditions. (b) Foliowing the tests of paragraph 7.2, the instrument or dummy load shall have re
25、- mained in its mounting and no parts of the instrument or its mounting base become detached and free of the shock tested equipment. Vibration: the test, it shall operate electrically and mechanically and the requirements of paragraph 5.1 shall be met. met, at standard conditions. The instrument sha
26、ll be subjected to the tests of DO-160, paragraph 8.2. During Following the test, the requirements of paragraph 4.0 of this Standard shall be Power Input: (a) Ndrmal Electrical Input Varaition Test 1. The instrument shall be subjected to the tests of DO-160, paragraph 16.3.1. During the test , it sh
27、all meet the requirements of paragraph 5.1 of this Standard. 2. The instrument shall be subjected to the tests of DO-160, paragraph 16.3.2. During the test it shall meet the requirements of paragraph 5.1 of this Standard, (b) Abnormal Electrical Input Variations Test 1. The instrument shall be subje
28、cted to the tests of DO-160, paragraph 16.3.3. During the test, it shall operate electrically and mechanically, and degradation of performance is permissible. fire or smoke during the test of paragraph 16.3.3.2. input it shall meet the requirements of paragraph 4.0 of this Standard, There shall be n
29、o evidence of the presence of After returning to normal Copyright SAE International Provided by IHS under license with SAENot for ResaleNo reproduction or networking permitted without license from IHS-,-SAE AS*8021 BL 8357340 00341Y7 I W -5- I AS 8021 I 2. The equipment shall be subjected to the tes
30、ts of DO-160, paragraph 16.3.4. During the test, it shall work electrically and mechanically, with degraded performance. There shall be no evidence of the presence of fire or smoke during the test of paragraph 16.3.4.2. input it shall meet the requirements of paragraph 4.0 of this standard. The equi
31、pment shail be subjected to the tests of DO-160, paragraph 16.3.5. After returning to normal power input, it shall meet the requirements of paragraph 4.0 of this Standard. After returning to normal power 3. 5.6 Conducted Voltage Transients: The instrument shall be subjected to the tests of DO-160, p
32、aragraph 17. O. (a) Intermittent Transients - Following the tests of paragraph 17.3.2 or paragraph 17.4.1, as appropriate, the instrument shall meet the requirements of 4.0 of this Standard. ,. (b) Repetitive Transients - When the instrument is subjected to the tests of paragraph 17.4.2, it shall me
33、et the requirements of paragraph 5.1 of thisstandard. 5.7 Conducted Audio Frequency Susceptibility Test: tests of DO-160, paragraph 18.0. graph 5.1 of this Standard. The instrument shall be subjected to the During the tests, it shall meet the requirements of para- I 5.8 Audio Frequency Magnetic Fiel
34、d Susceptibility: of DO-160, paragraph 19.0. The instrument shall be subjected to the tests During the tests, it shall meet the requirements of paragraph 5.1 - I - of this Standard. 5.9 Radio Frequency Susceptibility and Emission Tests: tests of DO-160, paragraphs 20.0 and 21.0. of paragraph 5.1 of
35、this Standard. The instrument shall be subjected to the During the tests, it shall meet the requirements 5.10 Magnetic Effect: 5.11 Explosion: Instruments which are to be marked Explosion, Category E, shall be tested in The instrument shall be tested in. accordance with DO-160, paragraph 15.0. in ac
36、cordance with DO-160, paragraph 9.0. 5.12 FVaterproofness: Instruments which are to be marked Waterproofness, Category W, shall be tested in accordance with DO-160, paragraph 10.0. meet the requirements of paragraph 4.0 of this Standard. Following this test, the instrument shall Instruments which ar
37、e to be marked Hydraulic Fluid, Category H, shall be Following this test, the instrument shall 5.13 Hydraulic Fluid: tested in accordance with DO-160, paragraph 11.0. meet the requirements of paragraph 4. O of this Standard. 5.14 Sand and Dust: Instruments which are to be marked Sand and Dust, Categ
38、ory D, shall be tested in accordance with DO-160, paragraph 12.0. meet the requirements of paragraph 4. O of this Standayd. Following this test, the instrumen shall 5.15 Fungus Resistance: Instruments which are to be marked Fungus Resistance, Category F, shall be tested in accordance with DO-160, pa
39、ragraph 13.0. shall meet the requirements of paragraph 4.0 of this Standard, Foilowing this test, the instrument 5.16 Salt Spray: Instruments which are to be marked Salt Spray, Category S, shall be tested in Following this test, the instrument shall meet the accordance with DO-160, paragraph 14.0. r
40、equirements of paragraph 4. O of this Standard. Copyright SAE International Provided by IHS under license with SAENot for ResaleNo reproduction or networking permitted without license from IHS-,-SAE AS*802L Al W 8357340 0034150 8 AS 8021 -6- I 5.17 Case Grounding: Metallic or other conductive instru
41、ment cases shall be connected to aircraft ground through a connector pin. system ground. This may be the same pint used for input power low or 6. MINIMUM ACCEPTANCE TEST REQUIREMENTS UNDER STANDARD CONDITIONS : Tests shall be performed on each Direction Instrument produced to show compliance with th
42、e following paragraphs of this Standard: 4.1 Starting 4.2 Roll, Pitch, and Yaw 4.3 Heading Stability 5.5(b) 3. Transient Surge Test 7. TEST PROCEDURES: The following definitions of terms and conditions of tests are applicable to the equipment tests specified herein: 7.1 7.2 7.3 7.4 Atmospheric Condi
43、tions: Unless otherwise specified , all tests required by this Standard must be conducted at an atmospheric pressure of approximately 29.92 inches (760 mm) of Mercury, an ambient temperature of approximately +VF (+25OC), and a relative humidity of not greater than 85 percent. When tests are conducte
44、d with the atmospheric pressure or temperature substantially different from these values, allowance must be made or the variation from the specified conditions. Vibration to Minimize Friction: conducted with the instrument subjected to a vibration of 0.002 to 0,005 inches (0.05 to 0.03 mm) double am
45、plitude at a frequency of 25 to 33 Hertz. The term “double amplitude“ as used herein indicates the total displacement from positive maximum to negative maximum. Unless otherwise specified, all tests for performance may be Power Conditions: rating recommended by the manufacturer. Unless otherwise spe
46、cified, all tests must be conducted at the power Mounting Position: (indicator , gyroscope , etc .) mounted in the normal operating position. Unless otherwise specified, all tests must be made with the instrument PREPARED BY SAE COMMITTEE A-4 AIRCRAFT INSTRUMENTS Copyright SAE International Provided by IHS under license with SAENot for ResaleNo reproduction or networking permitted without license from IHS-,-
