1、BRITISH STANDARD AEROSPACE SERIES BS M 89:1996 ISO 11995: 1996 Aircraft ground support equipment Stability requirements for loading and servicing equipment ICS 49.100; 49.120BSM 89:1996 This British Standard, having been prepared under the direction of the Engineering Sector Board, was published und
2、er the authority of the Standards Board and comes intoeffect on 15 September 1996 BSI 11-1998 The following BSI references relate to the work on this standard: Committee reference ACE/57 Draft for comment 94/700683 DC ISBN 0 580 26057 7 Committees responsible for this British Standard The preparatio
3、n of this British Standard was entrusted to Technical Committee ACE/57, Aircraft cargo systems and ground equipment, upon which the following bodies were represented: Association of Webbing Load Restraint Equipment Manufacturers British Airways British Narrow Fabrics Association Civil Aviation Autho
4、rity (Airworthiness Division) Health and Safety Executive Ministry of Defence Society of British Aerospace Companies Ltd. Society of Motor Manufacturers and Traders Ltd. Amendments issued since publication Amd. No. Date CommentsBSM 89:1996 BSI 11-1998 i Contents Page Committees responsible Inside fr
5、ont cover National foreword ii Introduction 1 1 Scope 1 2 Normative reference 1 3 Definitions 1 4 Objectives 2 5 Systems classification 3 6 Calculation formula 3 7 Test methods 7 Annex A (informative) Bibiliography 8 Figure 1 Representation of some parameters 4 Figure 2 Variation of “shape factor” w
6、ith aspect ratio for rectangular plates perpendicular to the flow 5 Figure 3 Determination of the distance from the centre of gravity to the pivot point 6 List of references Inside back coverBSM 89:1996 ii BSI 11-1998 National foreword This British Standard has been prepared by Technical Committee A
7、CE/57 and is identical with ISO 11995:1996 Aircraft Stability requirements for loading and servicing equipment, published by the International Organization for Standardization (ISO). A British Standard does not purport to include all the necessary provisions of a contract. Users of British Standards
8、 are responsible for their correct application. Compliance with a British Standard does not of itself confer immunity from legal obligations. Cross-reference Publication referred to Corresponding British Standard ISO 6966:1993 BS M 74:1994 Air cargo equipment. Basic requirements for aircraft loading
9、 equipment (Identical) Summary of pages This document comprises a front cover, an inside front cover, pages i and ii, pages1 to 8, an inside back cover and a back cover. This standard has been updated (see copyright date) and may have had amendments incorporated. This will be indicated in the amendm
10、ent table on theinside front cover.BSM 89:1996 BSI 11-1998 1 Introduction Throughout this International Standard, the minimum essential criteria are identified by the use of the key word “shall”. Recommended criteria are identified by the use of the key word “should”, and while not mandatory are con
11、sidered to be of primary importance in providing safe equipment. Deviation from the recommended criteria should occur only after careful consideration, extensive testing, and thorough service evaluation have shown alternate methods to be satisfactory. 1 Scope 1.1 This International Standard specifie
12、s: a) the criteria to be used to determine stability of aircraft loading and servicing equipment, including wind loads; b) the classification of systems recommended to achieve stability; c) the formula to be used for calculating steady-state wind stability; d) the recommended test methods applicable
13、 to equipment. 1.2 The intent of this International Standard is not to specify equipment design, but rather to define uniform criteria, calculation and testing methods in order to provide a safe work environment under all predictable circumstances for the users of aircraft loading and servicing equi
14、pment. 1.3 This International Standard specifies the worldwide requirements recognized by aircraft and equipment manufacturers as well as airlines and handling agencies. In addition, it shall be applied with due reference to national governmental regulations of the country where the equipment is to
15、be operated. 1.4 This International Standard applies to aircraft loading and servicing equipment, typically but not exclusively defined as follows: container and pallet loaders (seeISO6967 andISO6968); catering trucks (see ISO 10841); passenger stairs (see ISO 12056); maintenance and fueling access
16、platforms, when operated in a static position on an aircraft. 1.5 This International Standard does not apply to: forklifts; aircraft de-icers; any equipment with rotating booms, and more generally any equipment the normal mode of operation of which includes moving in the elevated position. 2 Normati
17、ve reference The following standard contains provisions which, through reference in this text, constitute provisions of this International Standard. At the time of publication, the edition indicated was valid. All standards are subject to revision, and parties to agreements based on this Internation
18、al Standard are encouraged to investigate the possibility of applying the most recent edition of the standard indicated below. Members of IEC and ISO maintain registers of currently valid International Standards. ISO 6966:1993, Aircraft Basic requirements for aircraft loading equipment. 3 Definition
19、s For the purposes of this International Standard, the following definitions apply. 3.1 wind movement of air which causes a force imposed on surfaces of aircraft loading and servicing equipment NOTE 1Wind in this context includes steady-state natural wind; wind gusts (temporary peak intensities); th
20、e effect of jet blast from other aircrafts engines. 3.2 stabilizers structural devices capable of supporting the weight of the equipment and any additional forces resulting from wind or other sources, used to reduce the lateral deflection of vehicles, when extended within the outer planview envelope
21、 of the vehicle NOTE 2Stabilizers will normally eliminate or reduce the part of the vehicles weight supported by tyres and suspensions. 3.3 outriggers stabilizers which, when extended, project outside the outer planview envelope of the vehicle NOTE 3Outriggers enlarge the supporting base of the vehi
22、cle. 3.4 tip point condition where the vehicle center of gravity has been rotated by the combined effect of load distribution, ramp slope, structural deformation if any, and the force of wind up to a point directly above the vehicles pivot pointBSM 89:1996 2 BSI 11-1998 3.5 pivot point that point of
23、 the vehicle in contact with the ground located farthest out on the most heavily loaded side or the side opposite to that to which the force of wind is applied 3.6 stability Condition where the laden or unladen vehicles center of gravity is located within the outer support perimeter, i.e.inward of t
24、he tip point; and the vehicles weight as well as the force of wind and any other forces are entirely supported by rigid structural elements. NOTE 4Where all or part of the vehicles weight and additional forces are supported by elastic elements such as tyres, suspension springs, etc., a dynamic condi
25、tion may be created that can exceed static and wind stability conditions as defined in 3.6.1 and 3.6.2. In such a case, appropriate additional safety margins should be determined to take into account possible dynamic effects resulting from support elasticity. 3.6.1 static stability stability achieve
26、d in a condition where, there being no wind or other additional forces, the vehicles tipping risk is determined only by load distribution (i.e. center of gravity location) and ramp slope 3.6.2 wind stability stability achieved in a condition where the force of wind constitutes the predominant factor
27、 of the vehicles tipping risk 4 Objectives 4.1 The static stability objective for any piece of aircraft loading and servicing equipment shall be for the vehicle to remain stable as defined in 3.6 when a) the vehicle is at maximum elevation, and b) the maximum allowable payload is concentrated on onl
28、y one half side of the vehicle (all on the same side of the vehicles centre line), and c) the vehicle, with stabilizers or outriggers extended when applicable, is standing on a surface at a slope of 3 (5 %) perpendicular to the vehicles centre line and sloping on the loaded side of the vehicle. 4.2
29、The wind stability objective for any piece of aircraft loading and servicing equipment shall be for the vehicle to remain stable as defined in 3.6 when the vehicle a) is at maximum elevation, and b) is empty, and c) is standing on a horizontal surface, with stabilizers or outriggers extended when ap
30、plicable, and d) is subjected to a steady-state wind of 120 km/h (65 kn), perpendicular to one long side of the vehicle. 4.3 The objectives for combined static and wind stabilities shall be as follows. a) The vehicle shall remain stable in the following conditions based on those defined for static s
31、tability in 4.1: maximum elevation allowed with or without stabilizers/outriggers; maximum payload asymmetry, or empty, whichever is the worst case; 3 (5 %) ramp slope, when simultaneously subjected to a steady-state wind of 75 km/h (40 kn), perpendicular to one long side of the vehicle in the same
32、direction as payload asymmetry and ramp slope. b) The vehicle shall remain stable in the following conditions: maximum elevation; symmetrical payload, or empty, whichever is the worst case; 1,5 (2,5 %) ramp slope, when simultaneously subjected to a steady-state wind of 110 km/h (60 kn), perpendicula
33、r to one long side of the vehicle in the same direction as the ramp slope. NOTE 5The objectives retained for combined static and wind stabilities are based on the following assumptions: aircraft manufacturers generally specify that the doors of a civil transport aircraft may not be opened or closed
34、by a wind exceeding 75 km/h (40kn), or remain open by a wind exceeding110km/h (60 kn) or 120 km/h (65 kn) depending on the aircraft type; operators therefore need to keep equipment fully functional by steady-state winds up to75km/h (40kn), still allowing for momentary wind gusts up to a maximum of 1
35、10km/h (60kn) without affecting safety. Operations on aircraft have to be stopped whenever gusts may exceed the latter value; any operation through wind gusts exceeding75km/h (40 kn) requires careful assessment of the weather forecasts at the airport, and specific operating rules to be issued and ca
36、refully applied. Such rules should include avoiding any payload asymmetry in the downwind direction or, on the contrary, deliberately maintaining a load asymmetry in the upwind direction and prohibiting the use of any aircraft stands with major slopes in the downwind direction. 1,5 (2,5%) was determ
37、ined to be the maximum normal ramp slope at international airports, excluding exceptional cases.BSM 89:1996 BSI 11-1998 3 5 Systems classification Systems recommended to achieve the required stability are as follows, in order of increasing effectiveness. A combination of some of the systems mentione
38、d in5.1 to 5.3 may be utilized to gain the desired stability. The choice of these systems is left up to the manufacturer because every vehicle is different in design and function. See ISO 6966 for general requirements. 5.1 Integral vehicle chassis methods a) Heavy-duty springs and auxiliary overload
39、 springs. These produce a harder ride, but provide increased side movement stability and assist in levelling off-centre loads when the vehicle is moving or stationary. b) Heavy-duty shock absorbers. These produce a harder ride but provide increased side movement stability while the vehicle is moving
40、. c) Tyre pressure. High tyre pressure on a vehicle increases the overall stability of either a slow moving or stationary vehicle, but produces a harder ride. d) Stabilizer bar systems. These increase stability by taking out chassis movement through a rigid bar or spring and can be applied in severa
41、l areas of the chassis. These systems do not adversely affect the ride of the vehicle as much as those defined in a), b), c) and e). e) Spring lockout systems. These block out the chassis springs against the axle and improve the stationary stability of a vehicle. Spring lockouts should not be engage
42、d while a vehicle is moving as this produces an extra hard ride and transmits all road shocks directly into the vehicle structure. 5.2 Stabilizer systems These systems generally utilize hydraulic cylinders with self-levelling foot pads that press against the ground within the envelope of the vehicle
43、. These systems stabilize the vehicle chassis when it is stationary by blocking out chassis movement on the springs and tyres. Usually stabilizers are used in tandem (one on each side of the vehicle) and placed at various key positions along the length of the vehicle. Two or more should be used as r
44、equired. 5.3 Outrigger systems These systems generally utilize hydraulic cylinders that extend self-levelling foot pads to the ground beyond the normal envelope of the vehicle, with heavy structural members that are connected to the chassis. The farther out from the chassis that these foot pads are
45、extended, the greater the resistance to tipping. NOTE 6Outriggers may result in interference with adjacent aircraft handling equipment, and hence should preferably be used only when stabilizers as described in 5.2 remaining within the equipment planview envelope, are proven not to be sufficient to m
46、eet the stability objectives of clause 4. 6 Calculation formula 6.1 The following formula should be used for calculating the steady-state wind stability (tip point) of aircraft loading and servicing equipment. 6.2 The formula is based on the following assumptions. a) The formula is applicable to the
47、 vehicles projected areas in its worst operating condition where stability is involved. This generally occurs when vehicle is at full extension and is unloaded. b) The air density is assumed to be 1,2kg/m 3(0,075 3 lb/ft 3 ), at standard temperature of 20C (68F) and atmospheric pressure of 101,3kPa
48、(14,7lb/in 2 ). If extreme temperatures and pressures (e.g. airport altitude) must be allowed for, the wind force should be corrected in proportion to the density. c) Wind velocity is considered as a steady-state wind condition. Aircraft jet blasts are also considered as a steady-state wind conditio
49、n, however they are likely to produce higher effective forces on the vehicle due to their dynamic (gust) nature. 6.3 The standard formula for calculating the tip point of the vehicle is M O= M RBSM 89:1996 4 BSI 11-1998 where 6.4 The overturning moment formula is where NOTE 7The corresponding formula in imperial units is where 6.5 The restoring moment formula is M R= Wd where M O is the total overturning moment, in newton metres, as defined in 6.4; M R is the total restoring moment, in newton metres, as de
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