Military

CHAPTER 2

AIR MOBILITY COMMAND AIRCRAFT

INTRODUCTION

This chapter describes Air Mobility Command (AMC) aircraft and provides the necessary planning data to effectively prepare load plans. Personnel who prepare load plans must recertify every two years.

The AMC aircraft of main concern are the C-130, C-141, C-5, KC-10, and C-17. With some exceptions, their cargo compartments can be configured to hold general bulk or palletized cargo, vehicles/equipment, troops, paratroopers, or cargo rigged for airdrop. The KC-10 cannot be rigged for airdrop. The wide range of cargo carried by these aircraft, along with many options for loading, provides great flexibility in moving troops and equipment.

Each of these aircraft have medium- to long-range mission capability. All are equipped with roller conveyor systems for using the 463L pallet system. The C-130, C-141, C-5, and C-17 have hydraulically activated ramp systems to ease loading and unloading. The C-141, C-5, KC-10, and C-17 also have aerial refueling capability.

NOTE: The planning data for the C-17 are projected capabilities only. They do not reflect the results of any DOD-certified tests and evaluations. Use only current data as a reference for possible future capabilities. Consult affiliated AMC representatives for actual "fly away" data.

ALLOWABLE CABIN LOAD

The load planner must know the approved allowable cabin load for a particular aircraft. ACL is the weight of unit personnel, equipment, and materiel that an aircraft can carry. Several varying factors, such as distance, route to be flown, fuel load, weather, and winds, impact on the ACL. Departure and arrival airfield characteristics also factor into determining the ACL.

For general airlift planning factors, use the following ACLs:


AIRCRAFT

ALLOWABLE
CABIN LOAD

  C-130

  25,000 pounds

  C-141

  50,000 pounds

  C-5

150,000 pounds

  KC-10

100,000 pounds

  C-17

153,500 pounds

AIRCRAFT CENTER OF GRAVITY LIMITS

Another factor to consider in load planning is center of gravity (CG) limits. Each aircraft has certain limits in which it must be balanced. If an aircraft is not balanced properly, it may not take off or land safely. In extreme cases, it cannot fly safely. The load planner directly affects this balance factor when loading cargo aboard an aircraft. Loads must not cause the aircraft to exceed its balance limits. The CG of any aircraft is the point on the aircraft at which the aircraft would hang in a level, balanced horizontal position if hoisted off the ground by a cable. It is an exact and specific point on the aircraft. Fortunately, through design characteristics and mechanical devices, each aircraft allows some variation with its CG. Otherwise, load planning would be almost impossible.

These variations, or CG limits, provide the load planner with flexibility in preparing various load configurations for each aircraft. As long as the effect of the cargo weight is kept within these CG limits, the aircraft can be safely operated.

CARGO LOAD CENTER OF BALANCE LIMITS

To keep the cargo weight within the aircraft CG limits, the cargo load center of balance (CB) must be identified. The combined center of balance (CCB) of the cargo load is then placed in the cargo compartment within a prescribed design limit for the aircraft. (See Chapter 5 for more information.) Table 2-1 provides AMC guidelines for use in airlift planning.

In general, floating CB criteria means as the cargo weight increases, the total cargo center of balance windows decrease. When total cargo weights fall between given weights, use the most restrictive (next higher) center of balance window. For example, a 46,000-pound load on a C-141 uses the 50,000-pound window of 880-950.

Unit air movement planning personnel must comply with established planning data when load planning unit equipment and personnel deployments by air.

The CB window numbers are referred to as fuselage station (FS) numbers. They represent the distance (in inches) aft from the aircraft reference datum (RD) line at which point the cargo load must balance. The FS numbers are clearly marked on the cabin walls to use as reference points when loading.

AIRCRAFT CHARACTERISTICS

Load planners must consider the characteristics of each aircraft. These characteristics include-

  • The size of the cargo door and its location and height above the ground.
  • The size and shape of the cargo compartment.
  • The strength of the aircraft floor.
  • The location, number, and type of seats available for airlifting troops.
  • Aircraft configurations (Appendix A).

If a complete file of Air Force publications is not available, the unit's affiliated AMC Airlift Control Squadron (ALCS) will assist the load planner. The ALCS is an extension of the unit's staff for all airlift planning. See FM 55-12 for more information on the affiliation program.

Table 2-2 is a quick reference for AMC aircraft. Refer to the individual aircraft discussed later in this chapter for more detailed information.

C-130 Characteristics

*Passenger Considerations. The C-130 does not have a separate passenger compartment, and passengers compete for available ACL. For planning purposes, estimate each passenger to weigh 210 pounds. This weight may vary with type of mission (refer to FM 55-12) and should be confirmed with AMC as early as possible. When using side-facing seats, plan for a maximum of 29 passengers. The C-130 will carry a maximum of 90 passengers (80 including flight crew for over water flight).

NOTE: Side-facing seats number 1 through 10 and 13 through 22 left and right must be installed in pairs. Seats 11 and 12 must be installed with 10 and 13 respectively, as these seats will not stand alone.

Palletized Cargo Restrictions. The C-130 can accommodate up to six 463L pallets. Usable surface dimensions of a 463L pallet are 84 inches long by 104 inches wide. Pallet criteria according to position, weight, and height are in Figure 2-2.

For pallet positions 3 and 4, maintain a 6-inch aisle along the narrow side of the pallet. Do not exceed an overall dimension of 84 inches long, 98 inches wide, and 96 inches high. This will provide the necessary aisleway for emergency exit of the aircraft.

For pallet position 6, maintain an 18-inch aisle. Pallet cargo dimensions will not exceed 86 inches wide, 84 inches long, and 76 inches high. This provides access to the latrine, cargo loading aids stowed in the cargo door, and to the aft escape exit hatch on the aft end of the cargo ramp.

Loading Guidance. The cargo area dimensions in Figure 2-3 are for general purposes only. Exceptions may include items configured according to TB 55-46-1 or loaded according to the aircraft loading manual. The schematic in Figure 2-3, extracted from DD Form 2130-2 (C-130 A/B/E/H Cargo Manifest), shows the fuselage station numbers and pallet position center of balances.

A number of loading aids are available to more conveniently load the C-130. They either come with the aircraft or are available as options from the supporting AMC TALCE or servicing aerial port. In addition to the primary loading aids in Figure 2-4, the following aids are available (all but the wheeled pry bars are in the aircraft):

  • Wheeled pry bars for handling boxes and crates in the cargo compartment.
  • A portable electric winch for moving cargo in and out of the aircraft.
  • Internal electrical power outlets to provide power for aids when loading the aircraft.
  • An auxiliary power unit to provide electricity and hydraulic pressure to assist aircraft loading.
  • A public address system consisting of loudspeakers, microphones, headsets, and extension cords for giving loading instructions and to control the loading operation.
  • Lighting to illuminate the cargo compartment and door area during night loading.
  • Snatch blocks (loading pulleys) to help move cargo in and out of the aircraft.

Rolling Stock Restrictions. Whenever possible, plan to load rolling stock on the treadways of the aircraft as shown in Figure 2-5. Vehicles with pneumatic tires must have a minimum space of 48 inches between axles. If this space cannot be obtained, the axles are considered as a single axle. When load planning and actual loading, the single axle limitations apply (Figure 2-5). Vehicles whose operational height exceeds 102 inches must be reduced in height unless certified to be shipped at a higher height according to TB 55-46-1 or the aircraft loading manual.

When the load consists of palletized cargo or floor-loaded cargo secured with cargo straps, maintain a 30-inch space between the cargo and the nearest forward occupied seat. When cargo is secured with chains, the 30-inch rule does not apply.

Do not exceed the following limitations:

  • Pounds per square inch.
  • Pounds per linear foot (PLF).
  • Axle weight.
  • Wheel weight.

Tracked Vehicle Loading. Figure 2-6 shows an M577 tracked vehicle loaded aboard a C-130 aircraft. The following example is the method to determine loadability and placement on the aircraft floor.

EXAMPLE:

A tracked vehicle is to be loaded aboard a C-130. The tracked vehicle weighs 22,000 pounds. The weight-bearing area of the tracks is 8 feet long (the length of track that contacts the cargo floor in longitudinal plane).

To determine the pounds per linear feet, divide the weight of the vehicle by the contact portion of the track. The answer is the amount of PLF being created.

22,000 pounds (weight of vehicle)
8 feet (floor contact area of track) = 2,750 pounds PLF

The vehicle creates 2,750 PLF. It can be safely transported, but it must be loaded between fuselage stations 337 to 682 (area where tracks must contact the aircraft floor). Allowable limit in this area is 3,000 PLF on the treadways.

Helicopter Loading. Helicopters with major disassembly can be airlifted. Table 2-3 provides data for use in mission planning (for specific guidance, refer to T.O. 1C-130A-9):

C-141 Characteristics

The C-141, nicknamed Starlifter, is a high-wing, heavy transport airplane with four turbofan engines (Figure 2-7). Its mission is to transport unit personnel, equipment, and materiel worldwide. The C-141 is the backbone of the strategic airlift capability of the US Air Force. It is most likely the aircraft to be used for all basic movement planning.

Passenger Considerations. Like the C-130, the C-141 does not have a separate passenger compartment. For planning purposes, estimate each passenger to weigh 210 pounds. This weight may vary with type of mission (refer to FM 55-12) and should be confirmed with AMC as early as possible. When using side-facing seats, plan for a maximum of 98 passengers. The C-141 will carry a maximum of 200 passengers (160 including flight crew for over water flights).

NOTE: All side-facing seats except number 1 left and right must be installed in pairs. Seat number 1 will not stand alone.

Palletized Cargo Restrictions. The C-141 can accommodate up to 13 463L pallets. Pallet position criteria according to position, weight, and height are in Figure 2-8.

Loading Guidance. The cargo area dimensions in Figure 2-9 are for general planning purposes only. Exceptions may include items configured according to TB 55-46-1 or loaded according to the aircraft loading manual. The schematic in Figure 2-9, extracted from DD Form 2130-3 (C-141B Cargo Manifest), shows the fuselage station numbers and pallet position center of balances.

*To more conveniently load the C-141, a number of aids come with the aircraft or are available as options from the supporting AMC TALCE or aerial port. With the exception of the ramp support, the C-141 aircraft has the same type of equipment listed Figure 2-4 for the C-130 aircraft.

Rolling Stock Restrictions. Whenever possible, plan to load wheeled and tracked vehicles on the treadways. Vehicles whose operational height exceeds 102 inches must be reduced in height unless certified to be shipped at a higher height according to TB 55-46-1 or the aircraft loading manual.

Do not load cargo that touches the floor or overhangs between fuselage stations 292 and 322. Do not stow any wheel loads outboard of the treadways next to the troop doors. The total combined loaded cargo weight between fuselage stations 322 and 678 will not exceed 45,000 pounds. Cargo loaded on the ramp for flight will not have the CB of cargo positioned aft of fuselage station 1473. When the load consists of palletized cargo or floor-loaded cargo secured with cargo straps, maintain a 30-inch space between the cargo and the nearest forward occupied seat. When cargo is secured with chains, the 30-inch rule does not apply. The part of a vehicle that is loaded under the crew rest facility (fuselage stations 322 to 378) will not exceed 80 inches in height measured from the aircraft floor. Do not exceed the limitations in Figure 2-10.

To determine aftmost axle location, use the following procedures (Figure 2-11):

Tracked Vehicle Loading. When planning air movement, there are two types of tracked vehicles: combat vehicles and construction vehicles. The basic difference is the rubber pad protection on the tracks that prevents damage to the ramp and the aircraft floor.

*All vehicles with metal tracks, cleats, studs, or other gripping devices that will damage the floor require rolling and parking shoring (see Chapter 6). For construction vehicles with cleats, the minimum thickness for rolling and parking shoring is 3/4 inch. Planking must be thick enough for cleats or lugs to sink into and for distribution of the load so as not to exceed aircraft limitations. Tracked vehicles with serviceable rubber pads do not require shoring if the aircraft floor limitations are not exceeded. Rubber pads must protrude beyond the steel track so that no portion of the metal track contacts the cargo floor.

Combat vehicles. Tracked combat vehicles have rubber pads on the individual track segments. Generally, they are limited to a maximum practical gross weight of 44,00 pounds. More specific limits are as follows:

MAXIMUM
AXLE WEIGHT
    (in pounds)    

 

MINIMUM
REQUIRED
 SHORING 

5,000

 

  3/4 inch

5,001 to 5,500

 

  1 inch

5,501 to 6,500

 

  1 1/2 inch

6,501 to 7,900

 

  2 inch

7,901 to 10,000

 

  3 inch

Approximate axle weights for vehicles with five axles or less by dividing the gross vehicle weight (GVW) by the number of axles minus 0.5. For example, the weight of a vehicle with five axles would be divided by 4.5.

Approximate axle weights for vehicles with six or more axles by dividing the gross vehicle weight by the number of axles minus 1.0. For example, the weight of a vehicle with seven axles would be divided by six.

*The following example shows how to determine the maximum axle weight for a tracked vehicle.

EXAMPLE:

Gross vehicle weight = 28,950 pounds

Number of axles = 5


5 axles or less = 

       GVW        
 number of axles -5

   28,950
 =   4.5   =   6,434

Computed load per axle = 6,434 pounds

1 1/2 inches of shoring is required.

*Construction vehicles. Tracked construction vehicles usually do not have rubber pads on the track segments. They are generally limited to a maximum practical gross weight of 44,000 pounds. Tracked vehicles with cleats require rolling and parking shoring. Shoring must be a minimum of 3/4 inch. Vehicles heavier than 32,500 pounds must be loaded straight in from a trailer or K loader. Vehicles that exceed any of these criteria or have unusual suspensions require special analysis and loading and shipping procedures. Load planners should obtain HQ AMC ALCS or affiliated ALCS guidance.

Helicopter Loading. Table 2-4 provides data for use in mission planning. (For specific guidance, refer to T.O. 1C-141B-9.)

C-5 Characteristics

The C-5, nicknamed Galaxy, is a high-winged, long-range, heavy-lift transport aircraft (Figure 2-12). Its primary function is to airlift outsized cargo. The aircraft is designed for global, intertheater operations. Unique features of this aircraft are the forward cargo door (visor) and ramp and the aft cargo door system and ramp. These features allow drive-on/drive-off loading and unloading. A vehicle can actually be driven through the aircraft.

The unit should not use the C-5 as a convenience to load planning. For general planning purposes, the C-5 is only used for cargo that is outsized to the C-141 aircraft. Unless operations orders state differently, cargo certified to fit the C-141 loading envelope will be planned on a C-141 aircraft. Higher priority missions may require HQ AMC/TACC to substitute C-5 aircraft for a ratio of C-141s. Units must maintain flexibility to allow for this type of change. Units must maintain open communications with their affiliated AMC ALCS for everyday guidance in this area.

Passenger Considerations. The troop compartment is in the upper deck area on the C-5 aircraft. It is a self-contained compartment with a galley, two lavatories, and 73 available passenger seats (CB at FS 1675). An additional 267 airline seats may be installed on the cargo compartment floor (maximum combined total of 329 troops including the aircrew over water).

*Palletized Cargo Restrictions. The C-5 can accommodate up to 36 463L pallets. Pallet criteria according to position, weight, and height are listed below.

PALLET
POSITION

 

MAXIMUM
WEIGHT

 

MAXIMUM
  HEIGHT*

1-2*

 

7,500 pounds

 

  96 inches

3-34

 

10,355 pounds**

 

  96 inches**

35-36*

 

7,500 pounds

 

  70 inches

*463L pallets loaded in pallet positions 1, 2, 35, and 36 shall have a 14-inch access aisle that will extend from the outboard edge of the pallet to the vertical stacking line of the cargo.

**Maximum single pallet weight for cargo secured with nets and stacked above 96 inches (not to exceed 100 inches) shall not exceed 8,000 pounds.

Loading Guidance. The cargo area dimensions in Figure 2-13 are for general planning purposes only. The schematic in Figure 2-13 , extracted from DD Form 2130-1 (C-5A/B Cargo Manifest), shows the fuselage station numbers and pallet position centers of balance.

The cargo compartment design, dimensions, and payload capability have been optimized to deploy units, personnel, equipment, and materiel. The compartment has a forward cargo door (visor) and ramp and an aft cargo door system and ramp. The visor door, when closed, forms the nose of the aircraft. The forward ramp extension is stowed in the vertical position. The aft pressure door, also used as a ramp extension, may be raised to a horizontal position to permit airdrop operations.

For general cargo and vehicular tie-down provisions, the cargo floor of the C-5 has 304 flush, permanently installed rings. Each ring can sustain a design limit load of 25,000 pounds. The tie-down rings are designed to receive either one hook from a 25,000-pound restraint device or two hooks from 10,000-pound restraint devices.

Another feature that facilitates and expedites loading and unloading operations is the kneeling capability. Kneeling the landing gear permits the cargo compartment floor to be lowered approximately 10 feet to about 3 feet above the ground. This kneeling feature was incorporated for two reasons: to facilitate loading operations by lowering the cargo ramps for truck-bed and ground loading and to reduce the ramp angles for loading and unloading vehicles.

Figure 2-14 shows the cargo floor and ramp angles for the kneeling condition. It also shows the C-5 nose up when aft-kneeled, nose down when forward-kneeled, and level when level-kneeled.

Note the dimensional data provided with the aircraft sections shown in Figure 2-15. The diagrams depict the front of the C-5 facing aft.

Figure 2-16 shows the details of the forward cargo opening with the visor in the raised position. The side profile of the cargo floor shows the ramp in the ground loading position in the stowed position. The front view of the cargo opening shows detailed dimensions of the opening.

To ground load or unload vehicles, the pressure door is hinged to the ramp as a ramp extension and lowered to contact the ground. Figure 2-17 shows the aft cargo ramp in the ground loading position.

Rolling Stock Restrictions. The cargo floor is a load-carrying structure across its whole width. Vehicles can traverse its whole area and maneuver freely during loading operations. In flight, single 36,000-pound axle loads or a combination of axles weighing up to 36,000 pounds may be carried on any continuous 40-inch longitudinal length of cargo floor area between fuselage stations 724 and 1884. Figure 2-18 also shows the in-flight loading limits on other floor areas and on the ramps. The capability of the ramps and floor are such that tanks and other tracked vehicles weighing up to 129,000 pounds can be loaded and transported.

Helicopter Loading. Table 2-5 provided data for use in mission planning. For specific guidance, refer to T.O. 1C-5A-9):

KC-10 Characteristics

The KC-10, nicknamed Extender, is a swept-wing, wide-body tri-jet with a dual-purpose mission as an aerial refueler and cargo/passenger aircraft (Figure 2-19). Unit personnel, equipment, and materiel are carried on the upper deck, and fuel tanks are contained in the lower compartments of the fuselage.

Passenger Considerations. When planning passenger movement on the KC-10, the limiting factor will be the configuration requested or approved (Appendix A). Planning weightn for passengers will be 180 pounds. The KC-10 may carry up to 69 passengers (69 over water).

*Palletized Cargo Restrictions. The KC-10 uses a rounded cargo compartment to maximize cargo-carrying capability. It can accommodate up to 27 463L pallets. Normally, a maximum of 25 pallet positions will be authorized. Usable surface dimensions of a pallet are 104 inches long by 84 inches wide. Due to location of pallet restraint rail systems in the KC-10, the 108-inch side becomes the length of the pallet. Pallet criteria according to position, weight, and height are in Figures 2-20 and 2-21.

For ease of planning, the two pallet profiles in Figure 2-22 will simplify pallet build-up. The two pallet profiles are--

  • 104 inches long x 84 inches wide x 70 inches high for pallet positions 2 through 10.
  • 104 inches long x 65 inches wide x 60 inches high for pallet positions 11 and 12.

These profiles may be exceeded to maximize use of the cargo compartment. However, the maximum profile limits (Figures 2-20 and 2-21) will not be exceeded.

Loading Guidance. The following cargo area dimensions are for general planning purposes only:

 

USABLE CARGO AREA

      Length - 1,416

      Width - 218

  *Height - 96

NOTE: Exceptions may include items configured according to TB 55-46-1 or loaded according to the aircraft loading manual.

The schematics in Figures 2-23 and 2-24, extracted from DD Forms 2130-6 and 2130-7 (KC-10 cargo manifests), show the fuselage station numbers, seating arrangements, and pallet position centers of balance.

Restraint criteria for other than netted cargo are as follows:

RESTRAINT CRITERIA*

DIRECTION

REQUIREMENT

 

Forward (with cargo barrier net)

1.5 g's

Forward (without cargo barrier net)    

9.0 g's

Aft

1.5 g's

Lateral

1.5 g's

Vertical

2.0 g's

 

*See Chapter 7, Cargo Restraint.

There is no provision for floor loading unit equipment or passenger baggage. All hand-carried items, such as crew-served weapons, rucksacks, and web belts, must either fit under the airline-style seating or be palletized.

Rolling Stock Restrictions. The unique loading requirements and limitations for the KC-10 require special attention. Any time the use of a KC-10 for airlift is anticipated, arrangements must be made for a wide-body loader at the location. Unlike other AMC aircraft, the KC-10 does not have a ramp at ground level to roll equipment on and off. The cargo door is about 15 feet above ground level. Also, unlike other cargo aircraft, the KC-10 cargo floor cannot withstand the stress of heavy axle floor loading. Therefore, the 463L pallets must be used as a subfloor whenever cargo or baggage is to be loaded aboard this aircraft. Also, because of the location of the cargo door, cargo width and height must be within the cargo door limits (Figure 2-25).

There are three acceptable loading methods for use with the 463L pallet. The actual method used to load equipment depends on numerous variables including allowable loading time and availability of materials-handling equipment (MHE). (Wide-body loaders, K loaders, and forklifts are needed to load and move pallets.) The methods are described as follows:

  • The first method is to prepalletize and secure cargo on individual 463L pallets before loading. This method requires the least amount of time for loading.
  • The second method is to place empty 463L pallets into the aircraft to create a pallet subfloor. The equipment is then driven or pushed into place and secured for flight.
  • The third method uses a combination of the first two methods. The combination method provides the flexibility for last minute changes and requires less use of MHE.

The pallet profile limitations also apply to wheeled equipment. In addition, allowable axle weights and axle separations (Figure 2-26 and 2-27) must not be exceeded. (Exceptions are allowed according to T.O. 1C-10(K) A-9. Section V outlines specific loading procedures for items that do not fit within general loading criteria or require a waiver of the aircraft limitations; for example, M-35A2 2 1/2-ton cargo truck [without winch], Figures 2-28, 2-29, and 2-30.)

Figures 2-31 and 2-32 show an example of a total CG problem. Figures 2-33 and 2-34 show an example of allowable lateral loading limits.

C-17 Characteristics

The C-17 is a high-winged, long-range, heavy-lift four-engine turbofan transport aircraft (Figure 2-35). It is designed to replace the aging C-141 fleet as the airlift workhorse. The C-17 can deliver outsized equipment into small austere airfields (SAAFs), previously restricted to the C-130. As of publication, the C-17 has not completed its test and evaluation program and the design freeze has not yet been accomplished.

Passenger Considerations. The C-17 does not have a separate passenger compartment. However, it has 54 side-facing seats permanently installed for passenger use in the cargo compartment. These sidewall seats do not affect the cargo area dimensions. For planning purposes, estimate each passenger to weigh 210 pounds. This weight may vary with type of mission (refer to FM 55-12) and should be confirmed with AMC as early as possible. The C-17 will carry a maximum of 102 passengers with centerline seats installed on the cargo floor (Figure 2-36). Also, up to 48 litters (Figure 2-37) may be installed (150 passengers, patients and medical crew over water based on life raft capacity).

Palletized Cargo Restrictions. The C-17 can accommodate up to 18 463L pallets--14 on the aircraft floor and 4 on the aircraft ramp (Figure 2-38). Figure 2-38 lists pallet position weight limitations.

Loading Guidance. The cargo area dimensions in Table 2-6 are for general planning purposes only (Figures 2-39 and 2-40):

The schematic in Figure 2-41 shows the fuselage station numbers and cargo tie-down locations.

Rolling Stock Restrictions. The cargo floor is a load-carrying structure across its whole width. Vehicles can traverse its whole area and maneuver freely during loading operations. In flight, single 40,000-pound axle loads or a combination of axles weighing up to 40,000 pounds may be carried on any continuous 42-inch longitudinal length of cargo floor area between fuselage stations 577 and 1072. Figure 2-42 also shows the in-flight load limits on other floor areas and on the ramps. The capability of the ramps and floor is such that tanks and other tracked vehicles weighing up to 129,000 pounds can be loaded and transported. Vehicles whose height exceeds 142 inches will not be planned forward of FS 971 (Figure 2-41). Vehicles whose height exceeds 142 inches but less than 158 inches will be planned aft of FS 971 or must be reduced to 142 inches.



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