1、 INCH PoE MIL-T-81259B(AS) 11 October 1991 SUPERSEDING MIL-T-81259A(AS) 14 Apri 1 1982 MILITARY SPECIFICATION TIE-DOWNS, AIRFRAME DESIGN, REQUIREMENTS FOR This specificatlon is approved for use by all Departments and Agencies of the Department of Defense. 1. SCOPE 1. Scope. This specification define
2、s the design and construction requirements for Naval Aircraft Tie-Down Fittings, Attachment Points, and the associated aircraft carry-through structures. 2. APPLICABLE DOCUMENTS 2.1 Government documents * 2.1.1 Specifications and standards. The following specifications and standards form a part of t
3、his document to the extent specified herein. Unless otherwise specified, the issues of these documents are those listed in the issue of the Department of Defense Index of Specifications and Standards (DODISSI and supplement thereto, cited in the solicitation (see 6.2). SPECIFICATION Mi 1 i tar! MIL-
4、A-8860 Airplane strength and Rigidity General Specificati.on for MIL-A-8867 Airplane Strength and Rigidity Ground Tests . MIL-A-8868 Alrplane Strength and Rigidity Data and Reports STANDARDS DOD-STD-100 Engineering Drawing Practices MI L-STD-805 Towing Fitting and provisions for Military Aircraft Be
5、neficial comments, (recommendations, additions, deletions) and any pertinent data which may be of use in improving this document should be addressed to: Naval Air Engineering Center, Systems Engineering and Standardization Department, (Code 53), Lakehurst, NJ 08733-5100, by using the Standardization
6、 Document Improvement Proposal (DD Form 1426) appearing at the end of this document or by letter. AMSC NIA FSC 15GP DISTRIBUTION STATEMENT A. Approved for public release; distribution is unlimited. Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-jMIL
7、-T-BL259B 35 q9999Ob 0492307 5 m 2.1.2 Other Government drawinus and publications. The following other Government drawings and-publications form a part of this document to the extent specified herein. Unless otherwise specified, the issues are those cited in the solicitation. DRAW I NGS Naval Sea Sy
8、stems Command 805-1 91 6300 - Aircraft Securing and Engine Run-up Fittings Naval Ai r Systems Command 993AS1 O0 - Aircraft Run-up Fitting Assembly Type XIII-Land-based 1 540AS 1 O0 - Tie-down, aircraft, type TD-1B 1540AS1 O2 - Hook PUBLICATIONS Naval Air Systems Command SD-24 - General Specification
9、 for Design and Construction of SD-8706 - Design Examination, Engineering, Aircraft Weapon Systems Aircraft Weapon Systems NAVAIR 17-1-537 - Tie-Down, Aircraft, Equipment and Procedures BULLETIN NO. 1 - Air Capable Ship Aviation Facilities (Unless otherwise indicated, copies of federal and military
10、specifications, standards, and handbooks are available from: Standardization Documents Order Desk, Bldg. 4D, 700 Robbins Avenue, Philadelphia, PA 19111-5094) * 2.2 Order of precedence. In the event of a conflict between the text of this document and the references cited herein, the text of this docu
11、ment takes precedence. Nothing in this document, however, supersedes applicable laws and regulations unless a specific exemption has been obtained. 3 REQUIREMENTS 3.1 Purpose of tie-down fittinus. Tie-down fittings shall be provided on the aircraft to permit securing the aircraft on the flight deck,
12、 hangar deck, or a land-based apron. They shall be so located that, without reliance upon wheel chocks, the installed tie-down lines will hold the aircraft in its intended position under the loads of 3.6. 3.2 Desiun criteria. The tie-down fittings, attachments and their carry-through structures shal
13、l be capable of supporting, without failure, the critical combinations of ultimate loads resulting from the load conditions and ultimate factor of safety specified herein. These structures shall be so designed and constructed that structural tests in accordance with MIL-A-8867 will demonstrate the s
14、tructural reliability and systems effectiveness for the planned service life of the aircraft. Permanent deformations that would adversely affect the operation and structural . integrity of the aircraft shall not result from the ultimate loads specified herein. 3.3 Load definition. 2 Provided by IHSN
15、ot for ResaleNo reproduction or networking permitted without license from IHS-,-,-? 1 MIL-T-BL259B 15 M 999990b 0492308 7 MIL-T-81259B(AS) 3.3.1 Limit loads. The loads, load factors, and load formulas in this specification and the reference specifications of 2.1 represent limit loads. 3.3.2 Ultimate
16、 loads. The ultimate loads are obtained by multiplying the limit loads by a factor of safety of 1.50. 3.4 Deformations. The effects of deformation of the aircraft tie-down fitt attachment points, and the carry-through structure shall be included in the determination of the magnitude and distribution
17、 of the limit and ultimate loads However, for the derivation of loads using strain energy methods the assumption the aircraft as a rigid body may be used if appropriate. of 3.5 Design allowables. 3.5.1 Design data and allowable materials properties. Design data, properties of materials, allowable st
18、ress values, and material strengths shall be in accordance Wi th MI L-A-8660. 3.5.2 Maunesium alloys. Magnesium-base-alloy parts shall not be used. 3.6 Desiun load determination. 3.6.1 Design limits loads. Design limit loads shall be derived from inertial forces caused by ships motion, wind forces o
19、n the aircraft, rotor lift, and engine thrust. Additionally, their derivation shall include the following: a. The aircraft shall be oriented at all angles with respect to the tie-down pattern and the longitudinal axis of the ship. The winds specified in Tables I and II shall be acting from all horiz
20、ontal directions. The inertia load of Table I or Table II, as applicable, shall act independently and in combinations. b. Under any possible combination of loads and conditions described herein, the maximum individual tie-down line load shall not exceed 10,000 pounds. For the determination tie-down
21、reactions in cases where their magnitude is not statically determinate, the reactions should be determined by rational or conservative methods. c. The ships motion inertial loads may be deleted from the derivation of limit loads in the determination of securing patterns for land-based tie-down condi
22、tions. d. The forces required for equilibrium of tied down aircraft, in combination with the loads resulting from each of the weather conditions of Table I or Table II, as applicable, shall be the reactions at the main and auxiliary wheels acting normal to the ground.or deck, and the tension loads i
23、n the securing lines attached to the normal weather, moderate weather, and heavy weather securing points provided. Horizontal loads shall not be reacted at the wheels. The critical combinations of loads resulting from wind, propulsion forces, lift forces, and inertial forces shal be distributed thro
24、ugh only those tie-down lines which can react to these combinations of loads. 1 e. For wings, tai assumed i n f. For normal weather and moderate weather conditions, the foldable portions of the folded positions and alternately in the extended positions. Is, rotors and other aircraft components that
25、can be folded, shall be - battens or heavy weather conditions, al 1 control surfaces shall be secured with locks that are provided for securing purposes. Jury struts, if provided for securing, shall be instal 1 ed, and the rotor blades shall be secured. 3 Provided by IHSNot for ResaleNo reproduction
26、 or networking permitted without license from IHS-,-,-:NIL-T-A1259B 35 999990b 0492309 9 . MIL-T-81259B(AS) g. For normal weather conditions defined in Table I or Table II, as applicable, rotary wing aircraft shall be secured to the normal weather tie-down fi tti ngs with rotor blades in the secured
27、 position, and alternately with engines assumed operating and rotor blades turning at all RPMs under all combinations of cyclic control varying from O to 25 percent, and pitch control varying from O to 50 percent, of the maximum available values of control. For shipboard operations, rotor blade iner
28、tial loads and inertial loads caused by ships motion shall be combined with wind and lift 1 oads . 3.6.1.1 Ships motion inertial loads. Ships motion loads are defined: Where : 1 Px, = location of nose gear tie-down fittings shall permit attachment of the tow bar without requiring removal of tie-down
29、 lines. 6 Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-P * * MIL-T-BL259B L5 W 9999906 0492LL2 9 = MIL-T-81259B(AS) f. Lower main gear. (2); (Note towing requirements of MIL-STD-805). e 3.7.2.2 Rotarv-winu aircraft. a. Upper main gear or upper mai
30、n gear structure (2). e. b. Upper auxi 1 i ary gear or upper auxi 1 iary gear structur c. Outboard on the main wheel axles. d. Aft fuselage. e. Forward fuselage. f. Additional tie-down fitting (SI as necessary to comply with rotary-w aircraft requirement of 3.6.1. 3.7.3 Recessed fittinus. For aerody
31、namic considerations requiring that fittings on the aircraft be recessed and covered by a door, the following requirements shall be met: a. The door or adjacent structure shall be properly labeled. b. A quick-release fastener shall be employed to provide access with a min effort. imum of c. The door
32、 shall be secured, when in the oDen Dosition, to- Drevent damage to the aircraft and el iminate a personnel hazard. - d. The door in the open position shall not interfere with tie-down lines when they are extended within the desired angles to pull-off. e. The door installation shall be such that the
33、 door can be secured in both the open and the closed position by only one crewman. f. The door shall be operable by a crewman during 60-knot winds either wearing or not wearing gloves needed for protection during cold weather. g. The door shall be capable of withstanding 100-knt winds from any direc
34、tion while in the open position. 3.7.4 Fittinu accessibility. The aircraft tie-down fittings shall be easily accessible to the crewman and shall clear the deck and ground in accordance with requirements of SD-24. Wing tie-down fittings shall be accessible when the wings are either folded and extende
35、d. 3.7.5 Aircraft tie-down patterns. Tie-down patterns for the aircraft shall be developed and presented pictorially in the Handbook of maintenance Instructions, showing the recommended location, allowable angular direction of pull-off, and number of tie-down lines required to secure an aircraft in
36、the specified weather conditions. Aircraft tie-down patterns shall meet the following general requirements. a. Figures 1, 2 and 3 show basic recommended tie-down patterns for fixed-wing aircraft. Simi lar patterns shall be shown for rotary-wing aircraft. The procuring requires more than 18 individua
37、l tie-down assemblies. e activity shall be informed as early as possible of any tie-down pattern that 7 Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-flIL-T-BL259B L5 W 999990b 0492LL3 O W. a YI MIL-T-81259B(AS) . c b. The aircraft tie-down pattern
38、s shall enable a simple, rapid securing of the c. The aircraft tie-down patterns shall not interfere with maintenance operations 8 d. .The aircraft tie-down patterns shall not interfere with the operation of aircraft. . which may be required while the aircraft is secured. aircraft access doors. e. T
39、he.aircraft tie-down patterns shall be compatible with existing tie-down and deck equipment and conforming to the procedures in NAVAIR 17-1-537.- f. The tie-down assembly shall be easily attached to and removed from the fitting without contacting the aircraft and external stores. g. The use of the t
40、ie-down line assemblies in series or in parallel should be avoided where possible. If the tie-down pattern should contain tie-down line assemblies in series or in parallel, then the procuring activity shall be notified as soon as possible. 3.8 Structural analysis and desiun data. Design, constructio
41、n, analysis, and test data and information shall be prepared to verify the strength, rigidity, systems effectiveness , and re1 iabi li ty of tie-down components, attachments, and carry-through structures to retain the aircraft in position when subject to the loads of 3.6. These data shall be prepare
42、d in accordance with MIL-A-8868 and SD-8706. 3.9 Data and information requirements relatinu to arrangement and usaue. 3.9.1 Tie-down arranuement drawing. Arrangement drawings, conforming to DoD-STD-100 and similar to figure 4, shall be prepared showing the tie-down arrangements for the weather condi
43、tions of TableI or Table II, as applicable. These drawings shall consist of a 1/20 scale three-view presentation of the aircraft in the static attitude. A deck and ground fitting pattern similar to that shown in figure 5 shall be shown superimposed on the three-view drawing. The tie-down lines shall
44、 be shown connecting the aircraft tie-down fittings to the deck and ground fittings, and all aircraft tie-down fittings and deck and ground fittings shall be shown. Clearances between the tie-down lines and the aircraft (including external stores) shall be provided in accordancw with 4.3.3 “High Poi
45、nt“ securing, which may require hangar bulkhead fitting installations in some cases, shall be clearly described in the appropriate arrangement drawing in accordance with Naval Ai r Systems Command Air Capable Ship Aviation Facilities Bulletin No. 1 3.9.2 Tie-down demonstration drawings. It shall be
46、demonstrated by use of overlay type drawings that the aircraft can be secured for random placement of the aircraft on deck tie-down fitting patterns as noted in Table III. All aircraft that are capable of operating on air-capable type ships shall also be able to adapt to a 42 inch by 42 inch deck fi
47、tting pattern spacing. Tie-down patterns for land-based operations shall be in accordance with NAVAIR 17-1-537. 3.10 Tie-down procedure report. A tie-down procedure report shall be submitted to the naval Air Systems Command for acceptance. The report shall include step by step tie-down procedures an
48、d requirements, using NAVAIR 17-1-537 as a guide. The procedures report shall include drawings which indicate, for all tie-down fittings, the coordinates of the aircraft fitting location similar to Figure 6, and the limitations in angular pulloff. The reasons for the limitations shall be clearly sta
49、ted in the text. Any tie-down lines that are used in parallel should be clearly 8 Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-4 t MIL-T-BL259B L5 E 9999906 0492334 2 E MIL-T-81259B(AS) Clearance, as shown in Figure 7, shall be indicated by that portion of the a cone generated by a tie-down chain of either 118“ or 136“ maximum length in deck or ground fitting may be located without
