GB/T 23420-2024Aircraft lower deck container cargo loader (English PDF)

3 Terms and definitions

3.1 main platform: the device at the rear of the loader that mates with the container and pallet dolly, can be raised and lowered, can rotate through 360° and can move containers and pallets fore and aft and from side to side.

3.2 front platform, called the bridge platform in the body of the document: the device at the front of the loader that mates with the aircraft door, can be raised and lowered and can move containers and pallets fore and aft and from side to side.

3.3 operation platform: the working area on the bridge platform where the control switches and the indicating instruments and lamps of the loader are placed and from which the operator can drive the loader, load and unload cargo and control the other related functions.

4 Classification

By power source, loaders fall into three classes: internal combustion, in which travel and operation are both powered by a fuel engine; electric, in which travel and operation are both powered by a rechargeable energy storage system; and combined, in which travel and operation are powered by a combined power source made up of fuel, a rechargeable energy storage system and mains electricity.

5 Technical requirements

5.1 General. The maximum lifting and conveying mass of the main platform and the maximum bearing and conveying mass of the bridge platform shall be marked in a conspicuous place on the loader. The outer paint coating shall meet 2.2 of QC/T 484-1999, the coatings and chemical conversion layers of components QC/T 625, and the welding of structural parts 3.4.6 of JB/T 5943-2018. There shall be enough working room at the points used for operation, maintenance and testing and along the routes used to change parts. There shall be no leakage of oil, of other liquids or of gas. Main bought-in parts shall have a works certificate of conformity. The pipework of the oil and air systems and the electrical system shall be neatly arranged and firmly clamped and shall not rub or interfere with moving parts. Wiring shall be run as cable or as a loom and shall be routed so as to guard as far as possible against wear, road splash and contact with grease, lubricating oil and fuel, and to prevent overheating. Terminals and numbering of electrical wiring shall carry durable clear markings for repair and maintenance, and electrical fittings, wiring and components shall all be easy to reach.

5.2.1 Basic safety. A night working light shall be fitted. Power steering shall be provided. At least one 8 kg dry powder fire extinguisher shall be carried on the chassis. A type C low intensity aircraft obstruction light meeting 5.3.1.2 and 5.3.1.3 of MH/T 6012-2015 shall be fitted in a conspicuous position. An automatic audible warning device shall be provided that sounds when the loader reverses or the lifting platform descends; when the reversing alarm sounds at the lower limit voltage of 10 V the sound level shall be within the range 75 dB(A) to 120 dB(A). Where the braking signal and the acceleration signal appear together, the machine control system shall respond to the braking signal first. Both the main platform and the bridge platform shall have a mechanical stability locking device for maintenance. The restrictions on the use of the equipment shall be marked clearly and permanently on the loader. An event data recorder (EDR) or an on-board video driving recorder shall be fitted. The filler caps of the fuel and fluid tanks and the charging socket shall be identified by colour as follows: green for diesel; white for water and coolant; yellow for lubricating oil; yellow with a blue stripe for hydraulic oil; black for the charging socket.

5.2.2 Operation platform. The platform shall be on the right of the bridge platform, shall follow the bridge platform up and down, shall be limited by the guides and lie outside them, and shall not affect the conveying of containerised cargo; its front end shall be extendable. A ladder shall be provided to let the operator get on and off the platform easily, and it shall be possible in any situation to climb from the ground onto the bridge platform. The width of the walkway for the operator shall be not less than 400 mm and the standing area not less than 0.5 m by 0.5 m. From the working position of the operator it should be possible to see the load being handled and the edge of the working platform clearly. The operation platform and the walkways shall have handrails or guardrails at a suitable height; the guardrail of the bridge platform shall be not less than 1 100 mm high and shall be adjustable. Anchor points for safety harnesses shall be provided on the operation platform. Clear working state indicating signals shall be provided on the console and their graphical symbols shall comply with MH/T 0023. The surfaces of the operation platform and of the walkways shall be treated against slipping, and anti-slip material shall be used for steps, ramps, ladder rungs, anti-slip strips and treads. The operation platform and the working surfaces shall be able to carry the rated number of persons, that is the operator on the operation platform and the staff on the working surface, each person counted as 110 kg. A ladder rung shall be able to carry a working load of not less than 110 kg.

5.2.3 Controls. Controls and warning lamps shall be grouped, and shall carry permanent identification, preferably using the graphical symbols of MH/T 0023. Controls shall be placed where the operator can reach them easily; where there are two or more working positions, an interlock shall be provided at each. The direction in which every control moves should agree with the direction of movement of the mechanism and of the cargo it controls, and controls shall have a safe logic control function or a safety locking function to prevent unintended stopping or reversal during operation. The position, size and operating room of hand and foot controls shall let the operator work wearing gloves and boots. The operating force of a hand control shall be not greater than 100 N. A foot control shall be not smaller than 50 mm by 75 mm, its operating force shall be not greater than 300 N and it shall be made of anti-slip material. The controls used to move unit load devices into and out of the aircraft shall be simple to work, so that one operator can position and handle the unit load device and open or close the hold door from the bridge platform.

5.2.4 Emergency devices. Towing attachments shall be provided at the front and the rear of the chassis. The hydraulic valves and the electrical circuits shall have an emergency system for manual operation in the event of a fault. Power steering shall be provided and steering shall remain easy when the machine is towed without power.

5.2.5 Hydraulic system. A safety locking device shall be fitted on the barrel of the lifting cylinder to prevent unintended retraction of the piston rod. A safety device against overload or hydraulic shock shall be provided, the set pressure of the safety relief valve being not more than 1.1 times the rated system pressure. The capacity of the hydraulic tank shall cover the total oil volume with the cylinders fully extended and fully retracted, and the tank shall have a level gauge, an inspection opening and a drain plug. A hydraulic oil temperature alarm shall be provided.

5.2.6 Guarding. All doors shall have devices holding them open or closed; the door retaining devices of the loader shall be able to withstand a maximum wind speed of 120 km/h, and an open door shall not injure anyone. Loader accessories weighing more than 36 kg, or more than 15 kg where only one person is allowed to fit and remove them, shall have a device for lifting or moving them. Nip points that could cause a hazard, such as sprockets, gears, chains, belts, fans and pulleys not shielded by the loader structure or by a guard, shall be guarded. A red mushroom-head emergency stop button shall be placed where it is easy to reach below the console and the bridge platform; the original text then says that the start button shall immediately shut down the engine of an internal combustion loader, the main power supply of an electric loader or the power source of a combined loader. Buffer guards and anti-collision devices for approaching the aircraft shall be fitted to the parts that touch the aircraft. A power isolating switch shall be provided to keep unauthorised people from starting the loader, and a manual mechanical main switch cutting off the power supply shall be placed where the driver can reach it easily. Electrical boxes and enclosures, control components and electrical connectors exposed to the environment shall have a degree of protection not lower than IP65.

5.2.7 Mechanical parts. The loader shall have no hollows where water can collect and no channels where dirt can gather, or else shall have drainage at suitable points. Vibration levels shall be kept to a minimum and shall not harm the equipment or the operator. When conveying a rated load on a level surface, the mechanical efficiency of a powered or unpowered single-direction conveying surface carrying unit load devices, such as a roller deck or a track, shall be greater than 98 %, see Annex A; that of a multi-direction conveying surface, such as castors or a ball deck, shall be greater than 96 %.

5.2.8 Specific requirements. An internal combustion loader shall meet 5.2.1 to 5.2.7 and in addition: the direction and the surface of the exhaust shall be kept away from the aircraft, the fuel system, the electrical system and people; the fuel tank and its fittings shall be placed so as to be protected as far as possible against impact, so that fuel cannot drip onto the engine, the exhaust or electrical components, and with a clearance of not less than 50 mm between the fixing of the fuel lines and the exhaust lines and the electrical system; the exhaust system outside the engine manifold shall be fixed and placed not less than 75 mm from flammable materials and not less than 50 mm from the fuel, hydraulic and electrical systems, so that fluids cannot drip onto it and so that the exhaust cannot harm people, other equipment or materials. An electric loader shall meet 5.2.1 to 5.2.7 and, for protection against electric shock, functional safety, the energy storage system, the motor and its control system, fire and thermal runaway protection, the charging interface, alarms and prompts and the remote management interface, shall meet Annex B. A combined loader shall meet 5.2.1 to 5.2.7 and in addition: the charger shall be able to provide a report or certificate complying with national standards; pressing the emergency stop shall cut off the mains main supply; the insulation resistance between the power cables and between a power cable and earth shall be not less than 2 megohms; the mains input shall have earth protection and use a residual current circuit breaker; the loader shall not be able to travel while working on mains power; the loader shall not be able to travel while the cable is not fully wound in; the cable reel shall wind the specified length of cable tidily, mechanically for winding in and by hand for paying out; the reel shall work reliably, shall make paying out and winding in easy and shall take no more than 1 min for either; and the reel shall have a function preventing the cable from being dragged.

5.3 Structural safety factor. For plastic materials used in important load bearing parts such as the underframe, the scissor arms and the platforms, the structural safety factor calculated on the minimum yield strength of the material shall be not less than 2; for non-plastic materials, the factor calculated on the minimum ultimate strength shall be not less than 5.

5.4 Stability. At a wind speed of 120 km/h the loader at its maximum working height shall not overturn. A power driven, adjustable and reliable stabiliser shall be provided; it shall be marked with alternating black and yellow reflective bands and its pad shall be painted red. The stabiliser shall have the following protective functions: while it is not extended, the conveying system cannot work and the main platform cannot rise from its lowest position; if the system fails, the stabiliser cannot become ineffective; an operator warning device shall be provided that gives a warning while the stabiliser is not retracted; an emergency retraction function shall be provided that avoids injuring the operator; a safety device shall be provided so that the lifting height of the loader does not exceed a set value while the stabiliser is not deployed or engaged, the stabiliser being retractable only while the lifting height is below that set value; and an interlock shall be provided so that the vehicle cannot be driven while the stabiliser is not fully retracted.

5.5 Mobility performance. The outer diameter of the turning circle shall be not greater than the design value. The ramp breakover angle shall be not less than 3°. The main platform shall travel within the range laid down in the design, its lowest height being not higher than 480 mm and its highest height not lower than 3 550 mm. When travelling, the overall height of the loader should be not greater than 3 600 mm and the height of the top of the rollers with the bridge platform at its lowest position shall be not greater than 1 880 mm. The axle load shall not exceed the maximum design axle load and the load capacity of the carrying wheels shall be not less than the axle load. The maximum speed shall be not less than 10 km/h and the loader shall be able to travel at least 3 km at not less than 10 km/h. The minimum stable speed shall be not greater than 5 km/h and running at low speed shall be smooth and free from shock. Acceleration performance shall meet the design requirement. Service braking shall comply with GB/T 18849; when the accelerator pedal is released while running, the loader shall brake automatically and the stop lamp shall light automatically. The parking brake shall hold the vehicle well on a 7 % (4°) gradient without the driver assisting. The service brake operating force shall be not greater than 450 N and the parking brake operating force not greater than 300 N. In addition, the fuel tank of an internal combustion loader shall hold enough for at least 8 h of continuous operation, and the endurance of an electric loader shall meet the design requirement.

5.6.1 Platform load capacity. The main platform shall be able to carry two half size containers or one pallet; the bridge platform shall be able to carry one half size container or one half size pallet. Table 1 gives the standard base dimensions and maximum gross masses of lower deck containers and pallets by ISO 8097 base size code; its five columns are the type of unit load device, the ISO 8097 base size code, the length in millimetres and inches, the width in millimetres and inches and the maximum gross mass in kilograms and pounds. For pallets, code A is 3 175 mm (125 in) long by 2 235 mm (88 in) wide with a maximum gross mass of 6 804 kg (15 000 lb); code B is 2 743 mm (108 in) by 2 235 mm (88 in) with 4 536 kg (10 000 lb); code M is 3 175 mm (125 in) by 2 438 mm (96 in) with 6 804 kg (15 000 lb). For containers, code K is 1 562 mm (61.5 in) to 2 337 mm (92 in) long by 1 534 mm (60.4 in) wide with 1 588 kg (3 500 lb); code L is 3 175 mm (125 in) to 4 724 mm (186 in) long by 1 534 mm (60.4 in) wide with 3 175 kg (7 000 lb). The footnotes give the base dimensions of the half size container as 1 562 mm by 1 534 mm (61.5 in by 60.4 in) and of the full size container as 3 175 mm by 1 534 mm (125 in by 60.4 in), state that smaller containers such as P, Q and N can also be carried, and note that for contoured containers overhanging the base edge lengthwise the overhang may be between 368 mm (14.5 in) and 775 mm (30.5 in) depending on the type, for example 775 mm (30.5 in) for an AKC container and 445 mm (17.5 in) for an AKE container.

5.6.1 continued. The length of the main platform shall take two half size containers placed lengthwise. The width of both the main platform and the bridge platform shall let a pallet 2 438 mm wide pass. The front right of the bridge platform shall mate with a container hold door 1 780 mm wide, by means of a retractable extension or by adjusting the width of the bridge platform. Where the loader approaches or leaves the lower hold under the flap track fairing, the height of the part passing under the fairing shall be not greater than 2 800 mm, and any part exceeding that limit shall be able to fold or retract.

5.6.2 Platform power systems. The main platform and the bridge platform shall be able to move containers and pallets sideways or lengthwise, and the main platform shall be able to rotate them through 360°. The tail end and the side end of the loader shall be designed to be driven by the power transmission so that containers and pallets can be loaded and unloaded. The power conveying system shall be able to move containers and pallets at 0.3 m/s and the speed shall be adjustable. The bridge platform shall be able to adjust to the pitch, roll and height attitude of the aircraft, shall not hinder the opening and closing of the aircraft door, and shall be able to adjust containers and pallets sideways. After 30 min with the machine shut down, the platform lifting system carrying the rated load shall hold both platforms at their highest position with a sinking not greater than 3 mm/m of the maximum design height. One complete lifting and lowering cycle of the main platform shall take not more than 35 s. When a container or a pallet spans the two platforms, the height of neither the main platform nor the bridge platform shall change.

5.6.3 Stop boards and guides. The guides of the bridge platform shall be adjustable to the width of the container or pallet, the widths being 1 534 mm, 2 235 mm and 2 438 mm. Adjustable, removable guides shall be provided on the bridge platform along the whole length of both sides so that unit load devices are guided accurately into the aircraft, and the guides shall be adjustable sideways so that they line up with the guides inside the aircraft. Retractable stop boards shall be provided on the main platform. The original text of that provision states in successive sentences both that the four, or two, stop boards extend automatically and stay put when the main platform starts to rise and that they extend automatically and stay put when the main platform has risen to 559 mm; when the main platform descends to 1 520 mm above the ground, retraction of the stop boards can be controlled by the operator.

5.6.4 Stop devices. The automatic stop device of the bridge platform shall be set at the end next to the main platform, and shall rise when the main platform begins to descend and retract when main platform and bridge platform are level. The automatic stop devices of the main platform shall be set at both ends; when the platform is fully lowered the stop device at the tail end shall retract automatically and it shall extend when the platform rises, while the stop device at the end next to the bridge platform shall extend while the main platform is low and retract when the two platforms are level. The overhanging part of the container shall be taken into account when the position of a stop device is set. The height of every stop device shall be not less than 54 mm.

5.6.5 Safety devices. The lifting systems of the bridge platform and of the main platform shall have a safety device against abnormal falling. Both platforms shall have a mechanical locking device to make the stopping of the lifting mechanism reliable. A device preventing the main platform from overrunning the bridge platform shall be provided.

5.7 External lighting and light-signalling devices. Table 2 sets the colour and the number of the lamps: main beam headlamps, white, 2 or 4; dipped beam headlamps, white, 2; direction indicator lamps, amber, 2 at the front and 2 at the rear; stop lamps, red, 2; reversing lamps, white, 2 for vehicles longer than 6 m and for vehicles not longer than 6 m one fitted and one optional; fog lamps, front fog lamps white or yellow and rear fog lamps red, front fog lamps optional and rear fog lamps 1 or 2; position lamps, front position lamps white and rear position lamps red, 2 at the front and 2 at the rear; end-outline marker lamps, front white and rear red, required on vehicles wider than 2.1 m, 2 at the front and 2 at the rear.

5.8 Reliability. During operation the loader shall not suffer damage to important parts or a serious fall in conveying capacity. On good roads the loader shall travel 500 km without a fatal failure.

5.9 Environmental adaptability. Under the rain conditions of Table 3 every part of the loader shall work normally; Table 3 sets two conditions, the front of the body at a rain intensity of 12 +/- 1 mm/min for 15 min and the sides, rear and roof of the body at 8 +/- 1 mm/min for 15 min. After running 500 m at maximum speed in a pool 100 mm deep the loader shall still travel and work normally, and it shall be able to charge normally where standing water on the ground is not deeper than 100 mm. The loader shall work normally at an ambient temperature of -15 °C, at an ambient temperature of 45 °C with a relative humidity of 50 %, and at a temperature of 40 °C with a relative humidity of 95 %, unless the user requires otherwise. The test methods and limits for electromagnetic compatibility shall comply with GB 34660 and GB/T 18387.

5.10 Environmental protection. The operating noise shall not exceed 85 dB(A) and the noise at the ear of the person at the operating position shall not exceed 90 dB(A). The exhaust pollutant emission limits of an internal combustion loader shall comply with GB 20891 and its exhaust smoke with GB 36886.

6 Test methods

6.1 Preparation. The measuring instruments used shall be selected according to the technical indexes of the parameters, shall meet the measurement accuracy required, shall have passed verification or have calibration results meeting the intended use, and shall be within their period of validity.

6.2 General requirements. Visual inspection covers the maximum lifting and conveying mass of the main platform and of the bridge platform, the working room at the points used for operation, maintenance, testing and part changing, and leakage of oil, liquid and gas. The paint coating is inspected visually as specified in QC/T 484-1999, the coatings and chemical conversion layers of the components as specified in QC/T 625 and the welded structural parts as specified in JB/T 5943-2018. The works certificates of conformity of the main bought-in parts are checked as documents, and the pipework, wiring and bought-in parts are inspected visually.

6.3 Safety requirements. The basic requirements, the operation platform, the controls, the emergency devices, the hydraulic system, the guarding and the mechanical parts are inspected visually. The loader is started and reversing and platform lowering are carried out separately to check whether the audible warning device sounds, its noise being measured with a sound level meter. The operator walkway, the working area, the guardrail height and the dimensions of the foot controls are measured with length measuring instruments; the operating force of the hand controls is measured with a force gauge; the load capacity of the operation platform, the working surfaces and the ladder rungs is checked with 110 kg standard weights; the degree of protection is checked as a document. For an internal combustion loader the exhaust arrangement, the fuel tank and its fittings and the exhaust system are inspected visually, and the distance between the fixing of the fuel lines and the exhaust lines and the electrical system, and the distance of the exhaust system from flammable materials and from the fuel, hydraulic and electrical systems, are measured with length measuring instruments. An electric loader is inspected as set out in Annex B. For a combined loader the test report or certificate of the charger is checked as a document; the emergency stop function, the interlock between cable and travel, the paying out and winding in of the cable reel and the anti-drag function of the reel are checked by simulation; the insulation resistance between the power cables and between a power cable and earth is measured with an insulation resistance meter; and the paying out and winding in times of the reel are measured with a stopwatch.

6.4 Structural safety factor. Strain gauges are bonded in the high stress areas and a measuring point layout is drawn up from the design calculations and the structural force analysis, with not fewer than 40 stress measuring points. The structural stress of the loader is measured, covering the underframe, the scissor arms, the platforms and the other main load bearing structures, under six conditions: bridge platform unloaded at its highest position with the main platform carrying the rated load and raised 100 mm, with the load placed at the front, in the middle and at the rear of the main platform in turn; the same with the main platform raised to half its maximum lifting height; the same with the main platform raised to its highest position; main platform unloaded at its lowest position with the bridge platform carrying the rated load and raised 100 mm, the load being placed in the middle of the bridge platform; the same with the bridge platform raised to half its maximum lifting height; and the same with the bridge platform raised to its highest position. From the static stress results, the 6 to 8 measuring points with the higher stress values are chosen and the dynamic structural stress is measured under the dynamic condition, the dynamic stress curve being recorded with an instrument. The dynamic condition is: the platform carrying the rated load rises at the rated speed from the lowest to the highest position and descends again from the highest to the lowest position, an emergency stop being made once on the way up and once on the way down during the first cycle, the second cycle being continuous.

6.5 Stability. It is calculated that with the loader unloaded, the main platform and the bridge platform raised to their highest position and a wind speed of 120 km/h, the anti-overturning moment is greater than 1.2 times the overturning moment; Formulae (1) and (2) are used. The original text gives the wind speed in that clause as 120 km/h followed by 65 kN in brackets, two quantities that are not of the same kind. Formula (1) states that the anti-overturning moment M equals 1.2 times the overturning moment M0, both in newton metres. Formula (2), which reached this workstation damaged by the extraction, is not reproduced; its key reads: V, the wind speed, in kilometres per hour; si, the area facing the wind, in square metres; hi, the height above ground of the centre of the area facing the wind, in metres; ci, the shape coefficient of the area facing the wind, obtained from Figure 1; n, the number of areas facing the wind. The note to Figure 1 states that b is the width and L the length of the area facing the wind.

6.5 continued. Visual inspection confirms whether the loader carries a power driven stabiliser, whether it is marked with alternating black and yellow reflective bands and whether the stabiliser pad is painted red. With the stabiliser not extended, the conveying system is started and the main platform is raised from its lowest position, and it is checked whether the conveying system works and whether the main platform can rise from its lowest position; the wording of that test step does not agree with the requirement of 5.4.3 a), which forbids both actions while the stabiliser is not extended. The stabiliser oil line is cut off and it is checked whether the stabiliser becomes ineffective. Visual inspection checks whether a warning is given while the stabiliser is not retracted. Visual inspection checks that the loader has a device for retracting the stabiliser in an emergency; the power source is cut off, the emergency device is operated, its effectiveness is checked and it is checked whether its position could injure the operator. With the stabiliser retracted, the platform is raised and the lifting height at which the platform stops automatically is measured with length measuring instruments and judged to exceed the design value of the manufacturer; the platform is then raised within the set value of the manufacturer and the stabiliser is retracted to check that it can be retracted, and raised beyond the set value and the stabiliser retracted to check that it cannot. With the stabiliser left not fully retracted, it is checked whether the vehicle can be driven.

6.6 Mobility performance. The outer diameter of the turning circle is measured as specified in GB/T 12540; the approach angle, departure angle and ramp breakover angle as specified in GB/T 12673; the height of the loader, the roller height at the lowest position and the travel range of the main platform with length measuring instruments; the mass parameters as specified in GB/T 12674; the maximum speed as specified in GB/T 12544; the minimum stable speed as specified in GB/T 12547; the acceleration performance as specified in GB/T 12543; and the braking performance as specified in GB/T 18849. For continuous running, the loader unloaded and in the gear under test is checked for its ability to travel 3 km at maximum speed. For the parking brake, the loader is driven onto a 7 % gradient, the parking brake is applied and after it has come to rest it is watched for 5 min, during which the loader shall not move at all, the test being made once facing up the slope and once facing down; the parking hand brake force is measured at the same time. If no such gradient can be found, the test may be made on a lesser gradient with added load, the added load being calculated from Formula (3); that formula reached this workstation damaged by the extraction and is not reproduced. Its key reads: delta G, the load to be added, in kilograms; G, the kerb mass of the loader, in kilograms; alpha, the actual test gradient, in per cent. The hand brake operating force is measured with a force gauge and the foot brake operating force with a pedal force gauge.

6.6 continued. For the endurance of an internal combustion loader, the fuel tank is filled, a starting point is set and the machine runs the cycle of Annex C until the lower fuel limit set by the manufacturer is reached or the fuel warning lamp lights; the distance travelled by the test machine, the number of operating cycles, one cycle being a full lifting and lowering of the machine and the conveying of a rated load forwards or backwards, and the fuel consumed are recorded, the measured values being rounded to whole numbers, and it is calculated whether the tank capacity covers at least 8 h of continuous operation. For an electric loader, the machine is fully charged, a starting point is set and the cycle of Annex C is repeated until the charge shown by the machine reaches the set value or the energy storage system gives an alarm; at the end of the cycle the distance travelled, the number of operating cycles and the elapsed time are recorded, the measured values being rounded to whole numbers, and the maximum speed, the average speed and the time taken by a single cycle during the test cycles are recorded as well.

6.7 Operating performance. With the main platform carrying two half size containers and the bridge platform one half size container, it is checked that both platforms can rise and descend through their whole travel; with the main platform carrying one pallet and the bridge platform one half size container, the same check is made. The lengths and widths of the two platforms, the width of the stop boards and guides or of the extension at the front right of the bridge platform, judged against a hold door 1 780 mm wide, and the height of the part passing under the flap track fairing are measured with length measuring instruments, and where the height limit is exceeded it is checked whether the excess part can fold or retract. Containers and pallets are placed on the two platforms and the controls are worked to check that lateral and longitudinal movement can be completed and that longitudinal movement is completed by the power drive system, and it is checked whether the longitudinal conveying movement of the bridge platform and the longitudinal and lateral conveying movement of the main platform are driven by the power system. The two platforms are levelled, a distance of 1 500 mm is set, a fully loaded container or pallet is moved over that distance, the time is measured with a stopwatch and the conveying speed is calculated. It is checked by what means the bridge platform can adjust to the pitch, roll and height attitude of the aircraft, whether the area where the bridge platform mates with the aircraft door affects the opening and closing of that door, and whether the bridge platform can adjust containers and pallets sideways.

6.7 continued. For the sinking test, the loaded platform is raised to its highest position, the machine is shut down and the power supply cut off; the platform height is measured with a laser rangefinder and the heights at the front, the rear, the left and the right of the platform are recorded separately; 30 min later the four heights are recorded again, the sinking at the four positions is calculated and the mean is taken as the 30 min sinking of the platform. The lifting and lowering times of the main platform unloaded and fully loaded are measured separately with a stopwatch and the corresponding speeds calculated, and the time of one complete cycle of the main platform is measured with a stopwatch. The two platforms are raised to the same height and a container or pallet carrying its rated load is moved between them to check whether the height of either platform changes as it spans the two. The width of the bridge platform guides is measured with length measuring instruments; it is checked whether the main platform has retractable stop boards and whether the bridge platform has removable guides adjustable to the width of the container or pallet, whether the guides run accurately along the whole length of both sides so as to guide the unit load device into the aircraft and whether they can be adjusted sideways to line up with the guides inside the aircraft; with the main platform raised to 559 mm it is checked whether the four, or two, stop boards extend automatically and stay put when the main platform begins to rise; the position is marked with length measuring instruments, the main platform is lowered and, when it is below 1 520 mm, it is checked whether the stop boards can be retracted by the operator.

6.7 continued. For the stop devices, it is checked whether the automatic stop device of the bridge platform is at the end next to the main platform; the main platform is raised level with the bridge platform and then lowered to check whether the stop device rises automatically, and raised again to the level position to check whether it retracts automatically; the automatic rising function is then disabled, the stop device is retracted by hand and it is checked whether the main platform can descend. It is checked whether the stop devices of the main platform are at its front and rear ends; the main platform is lowered and, when fully lowered, it is checked whether the tail end stop device retracts automatically, and the platform is raised to check whether that device extends; the main platform is raised from its lowest position to check whether the stop device at the end next to the bridge platform extends while the platform is low and retracts when the two platforms are level. The height of every stop device is measured with length measuring instruments. The hydraulic circuit diagram of the platform lifting system is inspected visually to check whether there are measures preventing the platform from collapsing if the lifting system fails, and a system fault is simulated to check whether the platform collapses; it is inspected visually whether the lifting mechanism has a mechanical locking device and its effectiveness is verified.

6.8 External lighting and light-signalling devices. The number and the colour of the lamps fitted to the loader are inspected visually item by item.

6.9 Reliability. The operating conditions are: both platforms rise from the lowest to the highest position, convey forwards, convey back, the bridge platform is lowered to its lowest position and then the main platform is lowered to its lowest position, this cycle being repeated 2 000 times; and the outriggers are extended and retracted through their whole travel 400 times. The operating reliability test is carried out under those conditions, after which it is checked whether the loader still works normally. Travelling reliability is tested as specified in GB/T 12678.

6.10 Environmental adaptability. For the rain test the loader is placed in the rain test chamber and rained on at the mean rain intensity of Table 3; when the rain stops, the driver operates the vehicle at once to check whether it runs normally and whether all the systems, controls, switches and other components work normally; after the rain test an electric loader has its steering motor, traction motor and electronic controller started to check whether they work normally. For the wading test the electric loader is placed in a pool 100 mm deep and it is checked whether it can travel a cumulative 500 m at maximum speed, taking about 3 min; where the pool is shorter than 500 m the run may be repeated until the cumulative wading distance reaches 500 m, the total time including the time out of the pool being not more than 10 min; the distance and the time are recorded and it is checked whether the loader travels and works normally, that is moves forwards and backwards, steers, brakes, lifts and conveys. The loader is also placed in the pool 100 mm deep to check whether it can charge normally. Low temperature testing follows GB/T 2423.1, high temperature testing GB/T 2423.2, damp heat testing GB/T 2423.3 and electromagnetic compatibility testing GB 34660 and GB/T 18387.

6.11 Environmental protection. The noise while the platform conveys and lifts the rated load is measured with a sound level meter at 4.6 m from the loader and 1.5 m above the ground, and the noise at the ear of the operator is measured as well. The exhaust pollutant emissions of an internal combustion loader are tested as specified in GB 20891 and its exhaust smoke as specified in GB 36886.

7 Inspection rules

7.1 Classification. The inspection of loaders is divided into delivery inspection and conformity inspection.

7.2 Delivery inspection. Every loader shall be inspected before it leaves the works, and shall be passed by the quality inspection department, which signs the product certificate of conformity. The items are given in Table 4. Table 4 lists ten items with the clause of the technical requirement and of the test method for each and shows whether the item is included in the delivery inspection and in the conformity inspection, a triangle meaning included and a dash not included. The items are: general requirements, 5.1 and 6.2, included in both; safety requirements, 5.2 and 6.3, included in both; structural safety factor, 5.3 and 6.4, conformity inspection only; stability, 5.4 and 6.5, included in both; mobility performance, 5.5 and 6.6, conformity inspection only; operating performance, 5.6 and 6.7, included in both; inspection of external lighting and light signals, 5.7 and 6.8, conformity inspection only; reliability, 5.8 and 6.9, conformity inspection only; environmental adaptability, 5.9 and 6.10, conformity inspection only; environmental protection requirements, 5.10 and 6.11, included in both. If any item of the delivery inspection fails, the loader shall be readjusted, corrected and tested again until it passes.

7.3 Conformity inspection. It shall be carried out when a new loader is type approved; when production is resumed after a stoppage of more than one year; when a change in the design, process or materials of the loader may affect its performance; when production is transferred to another works, or the delivery inspection result differs appreciably from the previous conformity inspection result; and when the civil aviation authority calls for an equipment conformity inspection. The items are given in Table 4. If any item of the conformity inspection fails, the failing item shall be tested again, and if it still fails the product is not qualified.

8 Nameplate, markings and instruction manual

8.1 Nameplate. The nameplate shall be marked clearly and permanently on the vehicle and shall contain at least the name of the loader; its model; the maximum lifting weight of the main platform in kilograms; the maximum bearing weight of the bridge platform in kilograms; the maximum speed in kilometres per hour; the overall dimensions, length by width by height, in millimetres; the kerb mass in kilograms; the works serial number; the date of manufacture; and the name of the manufacturer. For an internal combustion loader the nameplate shall also carry at least the engine model and the engine rated power in kilowatts. For an electric loader it shall also carry at least the model of the main drive motor, the power of the main drive motor in kilowatts, the rated and peak power of the motor in kilowatts, the type of energy storage system, its rated voltage in volts and its capacity in ampere hours. For a combined loader: where fuel and mains electricity form the combined power source, the nameplate shall meet 8.1.1 and 8.1.2 and shall also carry at least the rated voltage in volts, the rated current in amperes and the frequency in hertz; where a rechargeable energy storage system and mains electricity form the combined power source, it shall meet 8.1.1 and 8.1.3 and carry the same three additional items; where fuel and a rechargeable energy storage system form the combined power source, it shall meet 8.1.1, 8.1.2 and 8.1.3 together.

8.2 Markings. The specified pressure of the pneumatic tyres of the loader shall be marked. The fuel and hydraulic oil filling points shall be marked as required. Safety markings shall be provided at the potentially hazardous positions of the loader and lifting markings at the lifting points.

8.3 Instruction manual. The instruction manual shall comply with GB/T 9969.

9 Packaging, transport and storage

9.1 Packaging. Before the loader and its spare accessories are packed, any bare metal that has not been painted or electroplated shall be given temporary rust protection. The following documents shall be placed in the packing case: the product certificate of conformity, complying with GB/T 14436; the product instruction manual; the certificates of conformity and instruction manuals of the main matched components; the packing list; the list of spare parts and accessories supplied; and the product record book.

9.2 Transport. When the loader is carried by rail or by water it should be driven on and off the wagon or vessel under its own power. Where it must be loaded and unloaded by lifting, special lifting gear shall be used that will not damage the product.

9.3 Storage. For long term storage the coolant and the fuel shall be drained, the traction battery charged as specified, the power supply switched off and the doors and windows locked; the loader shall be kept on a site that is ventilated, damp-proof, shaded from strong sunlight and equipped with fire fighting facilities, and shall be serviced at intervals as laid down in the product instruction manual. The air in the room where the loader is stored shall be free from substances harmful to electrical insulation.

A Annex A (informative) Efficiency of roller type unit load device (ULD) loaders

A.1 Definition of efficiency. The requirements of ISO 4116 on roller size, characteristics and spacing are the minimum values needed to avoid damaging the ULD, and experience has shown that these values may not be enough to assure the efficiency of a roller type loader. The term efficiency as used below is defined as a ratio, given by Formula (A.1), whose key reads: e, the efficiency, in per cent; W, the mass of the ULD being loaded, normally the maximum mass of any ULD allowed to travel on the loader, in kilonewtons; F, the force needed to start the ULD moving when the roller system is in good repair and level, in kilonewtons. The test ramp is a climbing route made up of upward and downward sloping sections at a gradient of 10 % and a level section.

A.2 Efficiency targets. Efficiency is an important design element that bears directly on the saving of labour, for unpowered dollies or equipment, or on the total power requirement, for powered ULD equipment, and so also on the cost of use. The following targets apply to the design of roller type ULD equipment so that loading costs are properly reduced: within the normal range of usable ULD masses, the efficiency of the roller conveying system is not less than 98 %; within the same range, the efficiency of a multi-direction conveying system, castors or balls, is not less than 96 %, and for a castor system the castors are oriented at random or in the opposite direction before the force needed to start the ULD moving is measured.

A.3 Design tests for the rollers. Wide testing has shown that these design targets can be reached and held throughout the life of the equipment by following these basic rules: use rollers with continuous shafts of good quality ball bearings, so as to avoid deformation in service, the bearings being sealed at both ends and needing no lubrication; a shaft diameter or ball bearing inside diameter of not less than 19 mm; a roller surface of sufficient strength, a roller wall thickness of not less than 2 mm and an outside diameter of not less than 63 mm being suggested so as to avoid deformation in service; where the type of roller is unchanged, simply increasing the number of rollers, that is bringing the spacing below 200 mm, does not raise the efficiency of the roller system; and efficiency should be measured at various levels within the range of ULD gross masses rather than at the maximum, because the real efficiency factor of a well maintained roller system changes more slowly than the gross mass of the unit, see Figure A.1.

B Annex B (normative) Specific safety requirements and test methods for electric loaders

B.1.1 Protection against electric shock. Where protection is given by an enclosure or a barrier, class B live parts shall be inside the enclosure or behind the barrier, and the enclosure or barrier shall be openable or removable only with a tool. It shall meet at least degree of protection IPXXB as specified in GB/T 4208, and an enclosure or barrier that can be touched directly shall meet at least IPXXD. High voltage connectors shall be openable only with a tool, except in three cases: where the separated connector meets IPXXB; where at least two different actions are needed to separate the connector from its mating end and the connector is mechanically interlocked with some other mechanism that can itself be opened only with a tool before the connector is opened; and where the voltage of the live parts in the connector falls within 1 s of separation to not more than 30 V alternating current, root mean square, and not more than 60 V direct current. The note explains that electrical components and circuits are graded by maximum working voltage Umax as shown in Table B.1, which sets two classes in volts: class A, direct current above 0 up to and including 60 and alternating current, root mean square, above 0 up to and including 30; class B, direct current above 60 up to and including 1 500 and alternating current above 30 up to and including 1 000.

B.1.1.2 Protection against indirect contact. At the maximum working voltage the insulation resistance of direct current circuits shall be not less than 100 ohms per volt and that of alternating current circuits not less than 500 ohms per volt; where class B direct current and alternating current circuits are conductively connected together, the requirement of not less than 500 ohms per volt applies. The loader shall have an insulation resistance monitoring function: while the class B voltage circuit is energised and not conductively connected to an external supply, the device shall be able to measure the insulation resistance of the loader continuously or at intervals and, when that resistance falls below the threshold set by the manufacturer, shall warn the driver by a clear audible and visible signal. The live parts of the electrical system shall withstand the alternating voltage of Table B.2 at a frequency of 50 Hz or 60 Hz for 1 min; Table B.2 sets, in volts, basic insulation 2U plus 1 000 with a minimum of 1 500, supplementary insulation 2U plus 2 250 with a minimum of 2 750, and double or reinforced insulation 2U plus 3 250 with a minimum of 3 750.

B.1.2 Functional safety. A device shall be provided preventing unauthorised people from starting the loader, and going from the power off state to the ready to travel state shall take at least two operating steps. After a power cut the drive system shall restart only through the normal power-on procedure. On a loader with an energy storage system of 60 V direct current or above, the power system shall be isolated from the chassis. Where the drive system has taken measures reducing the drive power of the vehicle or limiting the power automatically and these affect travel, a warning shall be given by a clear signalling device. When the charge remaining in the energy storage system falls below a set value, a clear audible or visible signal shall give a prompt, and the remaining charge shall be enough to let the electric equipment reach the charging area, a travel distance of not less than 1 km, and to supply the lighting system. As regards the cut-off switch, on a loader whose superstructure is powered by the main drive motor, when the gear is not in neutral and the parking brake is not applied, the main drive circuit shall be cut off automatically 3 s to 5 s after the driver leaves the driving position; on a loader whose superstructure is not powered by the main drive motor, the main drive circuit shall be cut off automatically 3 s to 5 s after the driver leaves the driving seat. Cable connectors shall match the power cables and shall be firmly crimped, with a degree of protection not lower than IP55; connectors of 60 V direct current or above shall have a locking device and shall use an orange-red high voltage cable. While the charging or discharging cable is connected to the loader, the loader shall not move under its own drive system. For fault protection, the supply of the power system shall use a two-wire circuit design; where an auxiliary circuit is electrically connected to the power system, the auxiliary circuit shall be protected against excessive voltage; the travel motor shall have overcurrent protection and the steering motor short circuit protection; and with the loader travelling normally and the steering wheel at the maximum steering angle, the steering motor shall be able to work continuously and steadily.

B.1.3 Energy storage system. Its safety shall comply with GB 38031. The system and its box shall be firmly mounted. The system shall be placed in a box with a cover, the inner surface of the cover being coated with an insulating protective layer; the clearance between a metal cover and the live parts of the system shall be not less than 30 mm, and when a pressure of 980 N is applied over an area of 300 mm by 300 mm on the cover, the cover shall not touch the terminal face. The cover shall be closed tightly in normal use and shall not move. Suitable safety measures shall be provided for the box and the cover. The system shall be fitted with a battery management system, an on-line insulation monitoring device, a temperature alarm device and an automatic fire extinguishing device, lead-acid systems of 80 V direct current and below excepted. Its degree of protection shall be not lower than IP67, lead-acid systems of 80 V direct current and below excepted. A class B voltage energy storage or generating device shall carry the warning marking of Figure B.1, which shall comply with GB 18384 and GB 2893 and which shall be enlarged or reduced in proportion in use; where removing a barrier or an enclosure would expose class B voltage live parts, the same warning marking shall appear on that barrier or enclosure. On a loader with a lead-acid energy storage system, the installation including the cover shall have suitable ventilation openings, the inner surface shall resist chemical corrosion by the electrolyte, and protection shall be provided to keep electrolyte from running onto the ground. The creepage distance between the two terminals of a battery shall be not less than 0.25 times the nominal voltage between them plus 5, in millimetres, as given by Formula (B.1); the creepage distance between a live part and the chassis shall be not less than 0.125 times that voltage plus 5, in millimetres, as given by Formula (B.2).

B.1.4 Motor and its control system. These shall comply with GB/T 18488.1. The degree of protection of the motor shall be not lower than IP65 and its insulation class not lower than class H. No part of the motor shall use silicone material. When the motor works at the temperature limit of its insulation class, the electrical properties, mechanical properties and insulating quality of the enamelled wire shall not fall off. The travel motor should use the S2 60 min, S1 or S9 duty type. Where a steering motor is used, it shall use the S2 30 min, S2 60 min or S1 duty type and its degree of protection shall be not lower than IP65; the steering motor shall be such that the combined stresses and the temperature rise it undergoes do not cause any part to fail or deform excessively.

B.1.5 Fire requirements and thermal runaway protection. A clear audible or visible signalling device shall warn the driver that thermal runaway of the rechargeable energy storage system is about to occur, 5 min before thermal propagation caused by thermal runaway of a single cell. The energy storage system shall be fitted with a fuse and a manual maintenance switch. A manual emergency device shall be used to retract the stabiliser quickly so that a loader suffering thermal runaway can be moved away as soon as possible. For flame retardance, apart from the individual cells, the other non-metallic parts inside the energy storage system shall meet the following: a part meeting either of the conditions that its individual mass is not less than 50 g, or that the total mass of parts of the same model inside one energy storage system is greater than 200 g, shall be of a material meeting horizontal burning class HB and vertical burning class V-0 of GB/T 2408; other non-metallic parts shall be of a material meeting horizontal burning class HB75 and vertical burning class V-2. The energy storage system shall be fitted with a fire prevention and control device suited to its characteristics and complying with JT/T 1461.

B.1.6 Charging interface. The maximum rated voltage of the alternating current charging supply is 660 V with a permitted deviation of +/-10 % of the nominal voltage, and the rated frequency is 50 Hz +/- 1 Hz; the maximum direct current charging supply voltage is 1 000 V. All exposed conductive parts that may be connected to the supply shall be connected together so that, if a fault arises during charging, the fault charge on the vehicle body flows to earth; the resistance between all exposed conductive parts and the earth circuit shall be not greater than 0.1 ohm. The charging connection device shall comply with Clause 6 of GB/T 20234.1-2023, Clauses 4 to 7 of GB/T 20234.2-2015, Clauses 4 to 7 of GB/T 20234.3-2023 and Clause 5 of GB/T 27930-2023, and the loader identification code shall be added to the communication protocol. On a loader with wireless charging, the wireless charging system and device shall comply with GB/T 38775.1. The charging equipment shall meet the need for all-weather charging on the apron of a civil airport.

B.1.7 and B.1.8. Alarms and prompts shall comply with GB/T 19836 and GB/T 4094.2. An on-line monitoring terminal for the operating state shall be fitted and the data transmission format shall comply with GB/T 32960.3, so that the data collection needs of the user are met and key loader data such as the temperature, current and voltage of the energy storage system can be transmitted to the vehicle management system of the user in the network interface and format that system calls for.

B.2 Test methods. Protection against direct contact is checked by inspecting the protection given by the enclosure or barrier and by simulating a check of its degree of protection. For indirect contact, the insulation resistance of the direct current and alternating current circuits at the maximum working voltage is measured with an insulation resistance tester, the insulation resistance monitoring function is inspected visually and the withstand voltage of the live parts of the electrical system is tested with a withstand voltage tester. For functional safety, the device preventing unauthorised starting is checked and the steps from power off to ready to travel are checked by simulation; the way the drive system restarts after a power cut is checked by simulation; the power system and the chassis are inspected visually; the warning after drive power is reduced or limited automatically, and the signal prompt and the remaining charge when the charge of the energy storage system falls below the set value, are checked by simulation; the automatic cut-off of the main drive circuit after the driver leaves the driving position is checked by simulation; the degree of protection of the cable connectors is checked as a document and their locking device and cable colour visually; the interlock while the charging or discharging cable is connected is checked by simulation; the electrical schematic of the loader and the technical data of the travel motor controller and of the steering motor controller are checked as documents; and the stability of the steering motor at the maximum steering angle is checked by simulation. For the energy storage system, its certificate is checked as a document, the mounting of the system and its box is inspected visually, the technical documents of box and cover are checked and their safety measures inspected, the functional fittings of the system are inspected visually, the degree of protection is checked as a document, the warning markings on the system and on any barrier or enclosure are inspected visually, the ventilation openings are inspected visually and the inner surface checked as a document, and the creepage distance between two batteries is measured with dimensional measuring instruments. The certificate and the degree of protection of the motor and its controller are checked as documents. For fire and thermal runaway protection, the thermal runaway warning function is checked by simulation, the fuse and manual maintenance switch are inspected visually, and it is inspected visually whether the manual emergency device can retract the stabiliser quickly; the flame retardance certificates of the other non-metallic parts inside the system are checked as documents and the burning class of their material is checked; and the certificate of the fire extinguishing device is checked as a document and its fire prevention and control function inspected visually. For the charging interface, the supply voltage is checked as a document, the earth connection of the vehicle body is inspected visually, the resistance between the exposed conductive parts and the earth circuit is measured with a multimeter, the charging connection device is inspected visually and its communication technical documents checked, the certificate of the wireless charging system and device is checked as a document and the device inspected visually, and the charging state is checked by simulation. The certificate of the alarm and prompt functions is checked as a document, and the certificate of the data transmission format is checked as a document with the remote management interface function checked by simulation.

C Annex C (normative) Operating cycle for the endurance test

The equipment is unloaded and the test route is shown in Figure C.1. The sequence is: from point A, a simulated parking area, travel along the standard route for 1 km at the maximum safe speed and stop at point A prime; travel slowly for 20 m at the minimum stable speed and stop at point B, a simulated aircraft stand, lower the outriggers and raise the bridge platform to its highest position; convey a load suitable for the loader and at its full rating onto the main platform, raise the main platform to mate with the bridge platform and convey the cargo to the front end of the bridge platform, wait 2 min, convey the cargo back to the main platform, lower the main platform to its lowest position and convey the cargo off it; repeat that conveying to and fro 10 times, retract the bridge platform and the outriggers, travel slowly for 20 m at the minimum stable speed from point B, travel to point A prime and return along the standard route to point A, the simulated parking area, at the maximum safe speed. Those four steps make up one operating cycle, and during the test they are repeated without interruption.