1、1 MIL-I-26687C 66 m 9779906 013Li363 7 m . MI L- 1-2 6689C (USAF ) 10 JUNE 1981 . SUPERSEDING MIL-H-26689B (USAF) 13. October 1960 MILITARY SPECIFICATION INDICATOR, HORIZONTAL SITUATION, AQU-Z/A This specification is approved for use by the Department of the Air Force and is available for use by all
2、 Departments and Agencies of the Department of Defense. 1. SCOPE. 1.1 This specification covers the requirements for one type of horizontal situation indicator, designated AQU-Z/A. 2. APPLICABLE DOCUMENTS. 2.1 Issues of documents. The following documents of the issue in effect on date of invitation
3、for bids or request for proposal, form a part of this specification to the extent specified within. SPEC IFICATIONS Federa 1 I 1 P PP-B -601 Boxes, Wood, Cleated Plywood PPP-B-636 Boxes, Shipping, Fiberboard Mi I it ary MIL-P-116 Preservation-packaging, Methods Of MIL-C-675 Coating Of Glass Optical
4、Elements (Anti ref1 ection) DOD-D-1000 Drawings, Engineering And Associated Lists MIL-E-5272 Environmental Testing, Aeronautical And Associated Equipment, General Specificat ion For Add the following boxed paragraph to the bottom center of page: “Beneficial comments (recommendat-ions, additions, del
5、etions) and any pertinent data which may be of use in improving this document should be addressed to: HQ AFLC CASO/LODS, Federal Center, Battle Creek MI 49016 by using the self-addressed S.tandardization Document Improvement Proposal (DD Form 1426) appearing at the end of, this document or by letter
6、.“ FSC 6610 _I THIS DOCUMENT CONTAINS J$ PAGES. , Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-MI L-I-26689C (USAF) MIL-E-5400 Electronic Equipment, Aircraft, General Specification For MI L -C -5 541 Chemical Conversion Coatings On Al uini nuin An
7、d Al unii num Al 1 oys MIL-S-7742 Screw Threads, Standard, Optiriium Selected Series, General Specifica- MIL-Am8625 tion For Anodic Coatings, For Aluminum And Al unii num Al 1 oys MI L -L-2 546 7 Lighting, Integral, Red, Aircraft, Instrument, General Specification For MIL-L-27160 Lighting, Instrumen
8、t, Integral, White, General Specification For MI L-C-83488 Coatings, Aluminum, ION Vapor Deposited STANDARDS Federal FED-STD-595 Col or Mi 1 i ta ry MI L-STD-129 Marking For Shipment And Storage MIL-STD-130 Identification Marking Of U.S. Military Property MI L -S TD - 143 Standards And Specification
9、s, Order Of Precedence For The Selection Of MIL-STD-704 Aircraft Electrical Power Characteri st ics MI L-STD-826 Electromagnetic Interference, Test Requirements And Test Methods MIL-STD-838 Lubrication Of Military Equipinent MIL-STD-889 Dissimilar Metals (Copies of documents required by contractors
10、in connection with specific procurement functions should be obtained from the procuring activity or as directed by the contracting officer.) 3, REQUIREMENTS 3.1 First article. When specified (see 6.3), the contractor shall furnish sample unit(s) for first article inspection and approval (see 4.4). 2
11、 Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-MIL-I-2bb7C 66 7779706 OL3Li3b5 2 MIL-I -26689C (USAF) 3.2 Selection of specifications and standards. Specifications and standards for necessary commodities and services not specified herein shall be s
12、elected in accordance with MLL-STD-143 except as provided in 3.2.1 and 3.2.2. 3.2.1 Commercial parts. Comercial parts having suitable properties may be used where, on the date of invitation for bids, there are no suitable standard parts. In any case, commercial utility parts, like screws, bolts, nut
13、s, cotter pins, having suitable porperties may be used provided: They can be replaced by the standard parts (MS or AN) without alteration. in the parts list and, if practical, on the contractors drawings. 3.2.2 Standard parts. With the exceptions in 3.2.1, MS and AN standard parts shall be used wher
14、e they suit the purpose. They shall be identified on the drawings by their part numbers. a. b. The corresponding standard part numbers are referenced 6 3.3 Materials. 3.3.1 Fungus-proof materials. Materials that are nutrients for funai shall not be used where it is practical to avoid them. WheFe use
15、d and not hermetically sealed, they shall be treated with a fungicidal agent acceptable to the procuring activity. However, if they will be used in a hermetically sealed inclosure, fungicidal treatment will not be necessary. 3.3.2 Nonmagnetic materials. Nonmagnetic materials shalT be used for all pa
16、rts except where magnetic materials are essential. 3.3.3 Nonferrous materials. Nonferrous materials shall be used for all parts except where ferrous materials are essential, 3.3.4 Metals. Metals shall be of the corrosion-resistant type or suitablyreated to resist corrosion due to fuels, salt, spray,
17、 or atmospheric conditions likely to be met in storage or normal service. 3.3.5 Dissimilar metals. Unless suitably protected against electrolytic corrosion, dissimilar metals shall not be used in intimate contact with each other. Dissimilar metals are defined in MIL-STD-889. 3.3.6 Corrosive fumes. T
18、he materials as installed in the HSI and under the service conditions specified herein shall not 1 iberate deleterious fumes. O 3 Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-M I L - I - 2 6 6 8 9C 3.3.7 Hermetic seal. Nonferrous materials contain
19、ed within hermetically sealed inclosures (see 6.4.2), shall be considered suitably protected from corrosion. Requirements specified for fungicidal and corrosion protective treatment and anodizing of aluminum alloy parts shall not be applicable for parts within hermetically sealed inclosures. Steel p
20、arts within such inclosures shall be coated with ion vapor deposited aluminum, where practicable, in accordance with MIL-C-83488, type I or II as applicable and of a class that is adequate to achieve the degree of protection required. Other protective coating, in lieu of MIL-C-83488, may be used if
21、demonstrated to be satisfactory and approved by the preparing activity. Cadmium plating must be avoided when satisfactory alternative processes can be used. 3.3.8 Protective treatment. When materials are used in the construction of the HSI that are subject to deterioration when exposed to climatic a
22、nd environmental conditions likely to occur during service usage, they shall be protected against such deterioration in manner that will in no way prevent compliance with the performance requirements of this specification. The use of any protective coating that will crack, chip, or scale with age or
23、 extremes of climatic and environmental conditions shall be avoided. 3.3,9 Reclaimed materials. The use of reclaimed materials shall be encouraged to the iiiaximum extent possible without jeopardizing the intended end use of the item. 3*4 Design and construction. 3.4.1 Design. The HSI shall be desig
24、ned to present the fol lowing inforination: master directional reference source or desired heading, set in manually course, set in manually, displayed by a pointer and a numerical indication a. Stabilized magnetic compass heading provided from the b. Command heading inforination provided from a remo
25、te C. Command course provided from a remote source or desired d. Course bar which indicates displacement of the aircraft e. TO-FROM indication from a selected radio facility f, Numerical indication of distance to a transmitting radio from a manually or automatically selected track 4 Provided by IHSN
26、ot for ResaleNo reproduction or networking permitted without license from IHS-,-,-MIL-I-26689C source or target; indication masked when not in use g. Bearing to selected station or target 3.4.2 Construction. The HSI shall be so constructed that no parts will work loose in service. It shall be built
27、to withstand the strains, jars, vibrations, and other conditions incident to shipping, storage, installation, and service. The HSI shall be so constructed that overhaul, including replacement of worn parts, adjustment balance, and calibration may be accomplished by instrument and electronic repairme
28、n pravided with simplified tools and equipment, and trained in the repair of electronic equipment. 3.5 Performance. The HSI shall conform to all requirements specified herein after exposure to the following conditions: storage temperatures ranging from -65“ to t85“C a. Operating temperature ranging
29、from -54“ to t71“C and b. Altitudes from sea level to 100,000 feet c. Relative humidity up to 100 percent d. Fungus growth as encountered in tropical climates e. Exposure to salt-laden atmosphere f. Sand and dust partic g. Thermal shock forces of extreme temperature h. Vibration forces inc es as enc
30、ountered in desert areas as encountered during rapid changes dent to service use i. Immersion in water and leak test conducted with an approved helium leak detector, without evidence of leakage in excess of that specified herein aircraft j. Acceleration forces as encountered in high-performance k. T
31、he application of 250V DC for 10 seconds 3.5.1 Radio interference. The HSI shall not be a source of radio interference and shall meet the requirements of 3.5.2 Attitude. The HSI shall be capable of operating MIL-STD-826. 5 Provided by IHSNot for ResaleNo reproduction or networking permitted without
32、license from IHS-,-,-MI L - 1-2 6689C satisfactorily while in any attitude. 3.5.3 Friction error. A minimuni of error shall be introduced in the readings due to the friction between moving parts. 3.5.4 Magnetic effect. The HSI shall not cause excessive error in the indication of panel-mounted direct
33、ional magnetic compas ses . 3.5.5 Life. The HSI shall meet the performance requirements for 1,000 hours operation during actual service usage. 3.6 Interchangeability. All parts having the same manufacturers part number shall be functionally and dimensionally interchangeable. The drawing number requi
34、rements of DOD-D-1000 shall govern changes in the manufacturers part n umb ers . 3.7 Electronic requirements. The requirements specified in MIL-E-5400 are applicable as electronic requirements of this specification. Additional requirements shall be as specified herein. 3.7.1 Requirements conflict. I
35、n the event the requirements of MIL-E-5400 and this specification conflict, the requirements of this specification shall govern. 3.8 Miniaturization. Modern techniques of miniaturization, potting, and hermetic sealing shall be exploited to the greatest extent practicable without sacrificing ruggedne
36、ss, reliability, and service life. 3.8.1 Transistorized or magnetic amplifier circuits. Four transistorized or magnetic servo amplifiers shall be integral with the HSI mechanism within the HSI case. The amplifiers shall feature module plug-in capability, if possible. Each amplifier module shall be d
37、esigned with partial redundant circuits so that the servos will continue to operate, though with reduced performance, should partial failure of the amplifier occur. 3.9 Case. The HSI case shall be in accordance with figure 1. The dimensions of the cover glass aperture shown on figure 2 shall apply.
38、3.9.1 Control knobs. Control knobs as shown on Figure 1 shall be provided. The knobs shall be medium gray, color No. 36231 of FED-STD-595. The lettering of the knobs shall be block type. The inside of the case around the electrical connector shall be of sufficient strength to prevent damage to the c
39、ase when the 6 Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-MIL-I-2bb7C bb m 7777706 0134367 T m MI L-I -2 6689C electrical connector is tightened during installation. The case shall be metal, uniform in texture with a smooth surface, and entirely
40、 covered with a durable finish. The ends of the knobs shall be black with white lettering. A minimum of 2 inch ounces and a maximuin of 10 inch ounces shall be required to turn the knobs. Sealed fluid couplings may be utilized for the control knobs. 3.9.2 Cover glass. The cover glass shall be hermet
41、ically sealed within the HSI case and shall be mounted from the inside of the case. The cover glass shall be from 3/16 to 1/4 inch in thickness. It shall be flat and free from discolorations, except as induced by glare reducing coating, scratches, and striae which interfere with reading of the instr
42、ument. The cover glass aperture shall be as specified on figure 1, 3.9.3. Anti-reflection coating. A rnagnesium fluoride coating in accordance with MIL-C-675 shall be applied to each surface of the cover glass and the lighting wedge. Coated surfaces shall not chip, scale, peel, flake, dissolve, disc
43、olor, or otherwise be adversely affected in normal service use, The coatiny on the outer surface of the cover glass shall withstand abrasion incident to normal service usage. 3.9.4 Hermetic sealing. The case shall be hermeticalTy sealed. The design of the case shall be such that the internal mechani
44、sm may be removed from the case, replaced, and the case resealed. This shall be accomplished without the use of special tools and fixtures unless hey are approved by the procuring. activity. The hermetic sealing shall be so accomplished that the seal will not be dependent upon materials that will be
45、 affected by the action of any atmosphere to which the component may be subjected. The case shall be designed so that is will meet the necessary pressure requirements when tested for leaks by means of a mass-spectometer-type of he1 i um leak -detector. 3.9.4.1 Filling medium. The filling medium shal
46、l be of at least 98 percent purity, free of dust particles, and shall contain not inore than 0.006 milligram of water vapor per liter (dew point -65C) at the filling pressure. The filling medium shall be either 100 percent helium or a mixture of 88 to 92 percent nitrogen and the remainder helium. Th
47、e absolute pressure of the filling medium in the case shall be approximately 1 atmosphere. Where practicable, the 100 percent helium filling medium shall be ut i 1 i zed. 3.9.4.2 Leakage rate. The indicator shall be sealed so that the initial maximum leakage rate at a pressure differential of approx
48、imately 1 atmosphere will not permit more than 100 percent 7 Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-MI L - I -2 6689C loss of the total filling medium after 1,000 hours. 3.10 HSI dis la The display detail dimensions shall conform to one o 3.
49、10.1 Option A. The HSI display shall conforin to figures 2 and 4, All sizes of the pointers, azimuth card, deviation bar, numerals, and letters shall conform to the size and width listed on figures 2 and 4. The azimuth card, center section of the display, and main mask of the display shall lie in one plane, designated plane A, and shall be 0.7 20.05 inch from the forward edge of the cover glass. The forward edge of the heading marker sha
