1、NIL-A-81852A 66 777770b 0343706 3 t- t . SCOPE MILITRY SPECIFIC TIC ALTIMETER-ENCODER AAU-32/A This specification is approved for use by all Departments and Agencies of the Department of Defense. MIL-A-81 852A 20 Feb 1986 SUPERSEDING 6 Aug 1974 MI L-A-81852 1.1 This specification covers the requirem
2、ents for a counter-drum-pointer, integrally lighted, self-contained altimeter-encoder (indicator) having a range of -1,000 to 50,000 ft. with an encoded altitude output in accordance with the U.S. National Standard for Commmon System Component Characteristics for SIF/ATCRBS. 1.2 Classification. Two
3、types of altimeter-encoders are covered by this specification and differ only in respect to variation in color of the integral white lighting as follows: Incorporates “aviation red“ lighting and “blue filtered white lighting. Incorporates “aviation red“ 1 ighting and “instrument and panel“ white lig
4、hting. I. Type AAU-32/A-1 Al timeter-Encoder- (interchangeable with AAU-32/A) - II. Type AAU-32/A-2 Al timeter-Encoder (interchangeable with AAU-32AIA) - Beneficial comments (recommendations, additions, deletions) and any pertinent data which may be of use in improving this document should be addres
5、sed to: Commanding Officer, Naval Air Engineering Center, Systems Engineering and Standardization Department (SESD) Code 93, Lakehurst, NJ 08733, by using the self-addressed Standardization Document Improvement ProposaT (DD Form 1426) appearing at the end of this document or by letter. AMS C - N /A
6、FSC-6610 - DISTRIBUTION STATEMENT A. Approved for public release; distribution is un1 imi ted. / THIS DOCUMENT CONTAINS 49- PAGES. . - Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-MI L-A-81852A 2, APPLICABLE DOCUMENTS 2.1 Government documents. 2.1
7、.1 Specifications, standards and handbooks. The following specifications, standards, and handbooks form a part of this specification to the extent speclfied herein. Unless otherwise specified, the issues of these documents shall be those listed in the issue of the Department of Defense Index of Sr)e
8、cifications and Standards (DODISS) and the supplement thereto, cited in the soi i ci tation. MILITARY MIL-P-116 MIL-E-5400 MIL-C-5541 MI L-S-7742 MI L-A-8625 DOD-D-1 OOO/ 1 MI L-C- 1 4806 MIL-T-18303 MIL-C-25050 MI L-L-25467 MI L-C-26482 MIL-L-27160 MIL-6-27497 MI L-P-2 1 600 MIL-E-81 51 2 Preservat
9、ion, Methods of Electronic Equipment, Aircraft; General Specification for Chemical Fi lms for Al uminum and Al uminum Al loys Screw Threads, Standard, Optimum Selected Series; General Specif i cation for Anodic Coatings, for Aluminum Alloys and Aluminum Drawings, Engineering and Associated Data Coat
10、ing, Reflection Reducing for Instrument Cover Glasses and Lighting Wedges Test Procedures, Production, Acceptance and Life for Aircraft Electronic Equipments; Format for Colors, Aeronautical Lights and Lighting Equipment; General Requirements for Lighting, Integral, Aircraft Instrument; General Spec
11、ification for Connectors, Electric, Circular, Miniature, Quick Disconnect Lighting, Instrument, Integral, White; General Speci f i cati on for Bearing, Jewel, Sapphire or Ruby Synthetic Paint System, Fluorescent, for Aircraft Application Encoder, Shaft Position to Digital, Contact Type, Al ti tude R
12、eporting; General Specification for 2 Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-MIL-G-81704 STANDARDS FEDERAL FED-STD-595 MI LI TARY MIL-STD-130 MI L-STD- 1 43 MI L-STD-46 1 MIL-STD-471 MIL-A-81852A Glass, Aircraft Instruments, Lighting Wedges
13、and Cover Colors Identification Marking of U.S. Military Property Specifications and Standards; Order of Precedence for the Selection of Electromagnetic Interference Characteristics Requirements for Equi pment Mai ntai nabi 1 i ty Demonstration MIL-STD-704 MIL-STD-781 Reliability Tests, Exponential
14、Distribution MI L-STD-794 MIL-STD-810 Environmental Test Methods Electric Power, Aircraft, Characteristics and Utilization of Parts and Equipment, Procedures for Packaging and Packing of MIL-STD-859 Standard Calibration Table for Aeronautical Pressure Measuring Equipment MS-3113 MS-3114 MS-33549 MS-
15、33558 MS-33649 Connector, Electric Solder Type Solder Mounting, Bayonet Coupling Connectors, Receptacle, Electric Solder Type, Jam Nut Mounting, Bayonet Coupling Cases, Aircraft Instrument 2 314 Inch Dial Nith Sump, Standard Dimensions for Numerals and Letters; Aircraft Instrument Dial, Standard For
16、m-of Bosses, Fluid Connection, Internal Straight Thread (Copies of specifications, standards, handbooks, drawings and publications required by contractors in connection with specific acquisition functions should be obtained from the contracting activity or as directed by the contracting officer.) 3
17、Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-MIL-A-81852A 2.1.2 Other Government documents, drawings and pub1 i cations. other Government documents, drawings, and publications form a part of this specification to the extent specified herein. The f
18、ol lowing PUBLICATIONS Department of Defense Standardization SD-6 Provisions Governing Qualification (Copies available from: Commanding Officer, Naval Publications and Forms Center, 5801 Tabor Avenue, Philadelphia, PA 19120) DOD AIMS 65-852 Test Set, Automatic Altitude Reporting Encoders and Altimet
19、ers, Life TTU-229/E. (Copies available from: DOD AIMWTRACALS SPO, ESD (DCTP) S-27, L. G. Hanscom Field, Bedford, MA 017301 2.1.3 Order of precedence. this specification and the references cited herein, the text of this specification shall take precedence. In the event of a conflict between the text
20、of 2.2 Other publications. specification to the extent specified herein. which are indicated as DoD adopted shall be the issue listed in the current DoDISS and the supplement thereto, if applicable. The following documents form a part of this The issue of the documents Federal Aviation Agency U.S. N
21、ational Standard for Common System Component Characteristics for the IFF Mark X (SIF)/AIR Traffic Control Radar Beacon System, SI FIATCRBS (Application for copies should be addressed to the Federal Aviation Agency, Washington, DC 19120.) 3. REQUIREMENTS 3.1 Qualification. The general requirements fo
22、r qualification are specified in Publication SDL6, Provisions Governing Qualification. The production instruments furnished under the specification shall represent a product which has been tested and meets the qualification requirements specified herein under Section 4, Quality Assurance Provisions,
23、 and has been listed on or approved for listing on the applicable Qualified Products List. 3.1.1 Retention of qualification. Retention of qualification consists of periodic verification of compliance of the product with the requirements of this specification. The manufacturer shall provide a letter
24、of certification of compliance to the activity responsible for the Qualified Products List at intervals of not more than two years. A copy shall also be submitted to the Naval Air Systems Command, Attention Avionics Division. The letter shall 4 Provided by IHSNot for ResaleNo reproduction or network
25、ing permitted without license from IHS-,-,-t - MIL-A-L852A bb H 97997Ob OLLi37LO 5 H MI L-A-81852A attest that the qualified altimeter-encoder is still available from the listed plant and can be produced in the same plant under the same conditions as when qualified. manufacture of the altimeter-enco
26、der shall be reported as required by SD-6, Provisions Governing Qualification. Any changes in parts, materials, design, or processes for 3.2 Selection of specifications and standards. Specifications and standards for necessary commodities and services not specified herein shall be selected according
27、 to MIL-STD-143. 3.3 Standard general requirements of MIL-E-5400 Class 2 shall apply. 3.3.1 Non-magnetic materials. Non-magnetic materials shall be used for all sarts exceiot where maqnetic materials are essential. The extent to which magnetic materials ar required shall be reported to the procuring
28、 activity. 3.3.2 Protective treatment. When materials are used in the construction of the altimeter-encoder that are subject to deterioration when exposed to climatic and environmental conditions likely to occur during service life, they shall be protected against such deterioration in a manner that
29、 will in no way prevent compliance with the performance requirements of the specification. The use of any protective coating that will crack, chip or scale with age or extremes of climatic and environmental conditions shall be avoided. 3.3.3 Toxic and corrosive fumes. The materials, as installed in
30、the altimeter-encoder and under the conditions specified herein, shall not liberate deleterious or corrosive fumes. This shall include any fungicidal agents that are used. 3.3.4 Aluminum alloy parts. Aluminum alloy parts shall be covered with an anodic film conforming to MIL-A-8625, except that the
31、dial, small holes, case inserts, and fine pitch gear teeth need not be anodized. anodize sati sfactori ly may be coated in accordance with MIL-C-5541. Parts which do not 3.3.5 Components. The electronic and mechanical components shall be in accordance with MIL-E-5400. 3.3.6 Jewel bearings. All sapph
32、ire and ruby jewel bearings used in the altimeter shall be in accordance with MIL-6-27497. 3.3.7 Threads. The threads of all machine screws shall conform to MIL-S-7742. 3.4 Design and construction. 3.4.1 Features. The altimeter-encoder shall include the following features: a precision all-mechanical
33、 altimeter mechanism, a counter-drum-pointer type altitude display, integral red and white lighting, a barometric setting displayed by means of a four digit counter, and an altitude-encoder having outputs which correspond to the al timeter al ti tude di splayed throughout the applicable altitude ran
34、ge when the barometric setting is at 29.92. The encoder shall be capable of operating from both a 115 VAC, 400 Hz or a 28 VDC power source. Encoded al ti ude output meeting the performance requirements Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-
35、MIL-L52A -bb j MI L-A-81852A specified herein shall be provided whenever 115 VAC, 400 Hz or 28 VDC electrical power is applied to the appropriate pins of the electrical receptacle. Operation of the altimeter-encoder from a 115 VAC, 400 Hz power source is normally required for installations where the
36、 altimeter is used to replace the AAU-21 /A al timeter-encoder or where primary operation from an AC power source has been selected. operate the integral vibrator is usually 28 VDC from the eniergency power bus. It is intended that the altimeter-encoder be capable of operation of both the encoder an
37、d the vibrator from a nominal 28 VDC power source. the altimeter should provide for sustained operation under any of the preceding power conditions. position sensing or direct altitude encoding shall be such that when no electrical power whatsoever i s appl ied to the al timeter or its internal vibr
38、ator, the altimeter friction requirements for this mode of operation as specified in 4.5.6.1 shall be met. constructed that no parts will work loose in service and will withstand the normal shocks, vibrations and such other conditions as are incident to service, shipping, storage and installation wi
39、thout failure. In such cases, the electrical power to The design of Any component used in the altimeter mechanism for The altimeter-encoder shall be CO 3.4.2 Maintainability, The maintenance concept for this equipment shall be repair at depot level only. The encoder shall be removable as a subassemb
40、ly by means of an electrical connector(c) without disturbing the pneumatic portion of the altimeter. mechanism is permissible after reassembly of the encoder and electronics to the mechanism. Rezeroing of the altimeter by the encoder reset 3.4.2.1 Repair time. The altimeter-encoder shall be complete
41、ly repairable at depot level. depot technician and authorized depot AGE and technical information. Spare parts and facilities are assumed to be available. include all repair and test time excluding government or manufacturer acceptance testi ng The maintenance time shall not exceed 8 hours utilizing
42、 one Maintenance time shall 3.4.3 Mechanism adjustment. The mechanism shall be provided with a means of adjusting or correcting the indications to conform to the performance required herein, if this should become necessary during the life of the altimeter. The cal i bration adjustment shall not affe
43、ct the temperature performance of the instrument. This means of adjustment shall be reasonably simple to manipulate and of such nature that adjustment (rezeroing1 can be accomplished by tools ordinarily used by an instrument repairman. The adjustment shall be made in accordance with the manufacturer
44、s instructions (Government approved) at the level of maintenance for which such an adjustment is authorized by the government. 3.4.4 Barometric setting system. A setting system, controlled by a knob, shall be provided that will permit the altimeter display to be set to indicate zero altitude at any
45、existing ground level pressure throughout the range of 28.10 to 31.00 (inclusive) inches of mercury in 0.01 inch increments. The gear ratio between the setting knob and the display pointer shall be such that one complete revolution of the setting knob shall result in a display pointer movement of ap
46、proximately 200 to 300 ft. knob shall result in clockwise rotation of the pointer. The shaft of the setting knob shall be capable of withstanding a load of 15 pounds applied perpendicular to the shaft at the extreme outward end of the knob without Clockwise rotation of the setting 6 Provided by IHSN
47、ot for ResaleNo reproduction or networking permitted without license from IHS-,-,-MIL-A-L52A bb m 7779706 CIL43712 7 m MIL-A-81852A permanent deformation. A positive stop or stops shall be provided to limit the barometric setting mechanism movement such that the setting range of 28.0 to 31.1 inches
48、of mercury is not greatly exceeded. The setting system shall not introduce errors greater than specification tolerances when set at any point within the range established by the stops. The stops shall be capable of withstanding a torque of 6 pound inches applied to the barometric setting knob withou
49、t damage to the stops or the mechanism. If the design is such that the stops or the mechanism may be damaged by the application of 6 pound inches torque to the knob, the use of a torque limiting mechanism incorporated in the knob or in the instrument is acceptable if specification requirements are otherwise met. The design of such a device is subject to the approval of the qualifying agency. The resistance (torque) when setting the barometric pressure shall
