Extra Large Deployable Aircraft Hangar Systems


System Performance Specification (SPS)


for the

Extra Large Deployable Aircraft Hangar System







30 October 1998














Department of the Air Force


Eglin AFB FL





















Applicable Documents



System Description and Operating Requirements



Extra Large Deployable Aircraft Hangar System (XLDAHS) System Description, Functional, and Performance Requirements



System Description


XLDAHS Shelter Definition


ECS Definition



System Airlift Requirements



Shelter Structure






Structural Design






Safety Lanyard Support Structure






Severe Weather Partial Disassembly



Wind, Rain, and Moisture Resistance



Environmental Control System (ESC) Requirements



Design Conditions



ECS Capabilities




Aircraft Stabilization


Filtration System



Electrical Requirements






Switch Gear









Electrical Tools, Accessories, and Receptacles



Motor Starting



Lightning Protection



Electrical Grounding



Environmental, Safety, and Occupational Health (ESOH)



Compliance Requirements









System Safety Requirements



Human Performance/Human Engineering



Materials, Processes, and Parts






Corrosion Resistance



Fungi/Mildew Resistance



Ice Formation



Color and Colorfastness



Weather Performance



Tear Resistance



Fire Protection


Structural Components


Fabric Membrane



Solar Radiation and Ultraviolet Effects






Petroleum, Fuels, Oils and Lubricants



Logistics and Readiness



Operational Availability












Ship/Store Container



Nameplates or Product Markings








Levels of Maintenance


Maintenance and Repair Cycles


Support/Test Equipment






Personnel and Training


Shelter Support Requirements


ECS Support Requirements








Packaging, Handling, Shipping and Transportation (PHS&T)



Government Furnished Property



Qualification Tests and Certification





Annex A

463L Cargo System






Figure 1

B-2 Shelter Lighting Requirement






Table 1

XLDAHS Airlift Criteria


Table 2

XLDAHS Dimensional Criteria


Table 3

Exit/Entrance Requirements


Table 4

XLDAHS Climatic Design Criteria


Table 5

XLDAHS Basic Environmental Performance Matrix


Table 6

Thermal Characteristics of the B-2 Aircraft


Table 7

Electrical Load Requirement for Tools and Work Equipment.


Table 8

Existing and Required Receptacles


Table 9

ESOH Compliance Requirements


Table 10

C-141 Sortie Planning Factors


System Performance Specification

for the

Extra Large Deployable Aircraft Hangar System



1.1 Background. The B-2 Bomber Program Office has identified the need for portable hangars to support deployed operations. These hangars must be robust in construction to provide reliable protection for the aircraft and safety for the maintenance crew. They must also maintain stringent inside temperature and relative humidity conditions during B-2 aircraft maintenance operations. This System Performance Specification defines the Extra Large Deployable Aircraft Hangar System (XLDAHS). The objective of the specification is to outline the performance and physical characteristic requirements for a system that meets established physical and functional requirements for a B-2 aircraft maintenance hangar over a wide range of environmental conditions.

1.2 Mission. Air-transportable deployable shelters are an operational capability required to support (1) responses to major regional conflicts, (2) peace enforcement and intervention operations, (3) preparation for conflicts, (4) overseas presence, (5) readiness and sustainability, and (6) mobility and pre-positioning. There is a recent growing reluctance on the part of many countries to allow establishment of foreign military bases on their soil. To counter that eventuality and under the doctrine of "Global Reach... Global power" the USAF is prepared to deploy worldwide. Under this mission spectrum, the XLDAHS must be transported, erected and reconstituted quickly and, hence, the requirement for a light, low packed volume system that can be airlifted worldwide.


The following documents shall be complied with:

29 CFR

29 Code of Federal Regulations, Occupational Safety and Health

40 CFR

40 Code of Federal Regulations, Protection of the Environment

AFOSH Standards

Air Force Occupational Safety and Health Standards (AFOSH)

AISC Manual

Manual of Steel Construction Allowable Stress Design, Ninth Edition (If steel used)

AISC Manual

Manual of Steel Construction Connections ASD/LRFD, Volume II (If steel used)

Aluminum Manual

Aluminum Association Aluminum Design Manual - 1994


Minimum Design Standards for Buildings and Other Structures

ASTM E136-96a

American Society for Testing and Materials E136-96a, Standard Test

Method for Behavior of Materials in a Vertical Tube Furnace at 750*C

ASTM E84-96a

American Society for Testing and Materials E84-96a, Standard Test Method for Surface Burning Characteristics of Building Materials


BOCA National Building Code/1996

ISO 8879

Standard Generalized Markup Language (SGML)


International Safe Transit Association, Procedure 2 for Export Testing


National Electrical Code (NEC)


Methods of Fire Test for Flame Resistant Textiles and Films


Lightning Protection

UBC Standard 2-1

Uniform Building Code Standard 2-1, Noncombustible Material - Tests

UBC Standard 31-1

Uniform Building Code Standard 31-1, Flame-retardant Membranes

The following documents may be used as reference:

ACGIH Manual

Industrial Ventilation, A manual of recommended practice (Current edition), American Conference of Governmental Industrial Hygienists


Level of Repair Analysis (LORA)


Dissimilar Metals


Human Engineering Design Criteria for Military Systems, Equipment and Facilities


Designing for Internal Aerial Delivery in Fixed Wing Aircraft.


DoD Material, Procedures for Development and Application of Packaging Requirements


Climatic Information to Determine Design and Test Requirements for Military Systems and Equipment


Finishes, Protective and Codes for Finishing Scheme for Ground and Ground Support Equipment


Environmental Test Methods and Engineering Guidelines


Systems Safety Program Requirements


Assembly Seating, Tents, and Membrane Structures


Aircraft Hangars


3.1 Extra Large Deployable Aircraft Hangar System (XLDAHS) Description, Function, and Performance Requirements

3.1.1 System Description. The XLDAHS for B-2 aircraft maintenance shall include the shelter, the environmental control system (ECS), infiltration control measures, ventilation, heat/cooling load reduction measures, spares/repair kit, shipping/storage containers, electrical distribution equipment, and contents of the shelter structure, i.e., lighting, electrical wiring, receptacles, switches, and ECS controls. Wherever used in this document, the terms "Extra Large Deployable Aircraft Hangar System" and XLDAHS are synonymous.

The thrust of the following performance requirements is to provide a shelter system, including an ECS, that takes advantage of latest developments in HVAC technology, lightweight materials, and innovative techniques with the objective of minimizing airlift intensity while meeting the functional and operational characteristics of the shelter system. The system performance requirements are as follows:

        1. XLDAHS Shelter Definition. The term "XLDAHS shelter" will be used to refer to all equipment necessary to meet the requirements of this specification, excluding heating, cooling, and humidity control (ECS). The XLDAHS shelter shall meet the ventilation requirements of this specification. The XLDAHS shelter shall provide the capability to attach an ECS. ECS Definition. The term "Environmental Control System", or "ECS", will be used to refer to all equipment necessary to control temperature and humidity to the levels required by this specification.

3.1.2 System Airlift Requirements.
The XLDAHS shall minimize shipping weight and volume to the extent possible, without compromising the structural integrity of the system.

The XLDAHS, in its shipping configuration, shall be compatible with the 463L Cargo Handling System and conform to the parameters shown in Table 1: XLDAHS Airlift Criteria. Containers that are intended to be transported on their own base or which incorporate an integral pallet base, shall also be compatible with the 463L Cargo Handling System. For information purposes only, Annex A provides a description of the 463L pallet system.


Table 1. XLDAHS Airlift Criteria

Common Airlift Factors



Maximum axle load for wheeled equipment

20,000 pounds

5,000 pound individual wheel


Maximum tire pressure

For wheeled equipment

100 psi


Cargo Restraint Criteria; Load Factors




2.0 G up

4.5 G down

3.0 G forward

1.5 G aft

1.5 G lateral

(G = force of acceleration due to gravity)

Palletized cargo and containers, in their shipping configuration, shall be capable of being restrained to the criteria shown.

All equipment stored inside a container shall be restrained, within the container, to the criteria shown.

Rapid Decompression of Aircraft

Sealed containers must provide for controlled breathing to accommodate airflow to safely relieve an 8.3-psi pressure build-up within 0.5 seconds resulting from rapid decompression of the aircraft cabin.

Source: Military Standard 1791H

3.2 Shelter Structure.
The shelter shall have minimum dimensions as outlined in Table 2. XLDAHS Dimensional Criteria.

Table 2. XLDAHS Dimensional Criteria



Inside Clear Span

200 Feet Nominal

Center Clear Height

30 Feet Minimum

Inside Clear Height at 86 feet from centerline (each side)

22 Feet Minimum

Inside Clear Height at 96 feet from centerline (each side)

12 Feet Minimum

Inside Clear Length

At Centerline of Shelter

105 Feet Minimum

Personnel Doors

IAW BOCA National Building Code/1996, Chapter 10, Use Group F-1

Equipment Door

12 ft w x 10 ft h

For purposes of this document, the layout of the structure shall be defined as follows:

Front - The exterior face of the structure that includes aircraft ingress/egress opening.

Back - The exterior face of the structure opposite the aircraft ingress/egress opening.

Sides - The exterior faces adjacent to the front and back.

3.2.1 Openings. The XLDAHS shall include personnel doors per BOCA 1996 (Chapter 10, User Group F-1), one truck/equipment opening, six passes through openings for AGE support equipment and one aircraft ingress/egress opening. The aircraft ingress/egress opening shall be at least 192 feet wide from the floor to 12 feet above the floor and at least 184 feet wide from 12 to 16 feet above the floor, and at least 176 feet wide from 16 feet above the floor to the top of the opening. The top of the opening shall be at least 20 feet high. Normal operations shall allow the XLDAHS ingress/egress opening for the aircraft to be capable of being opened in 2 minutes or less with a trained crew of no more than 2 people. During an emergency, The XLDAHS ingress/egress opening for the aircraft shall be capable of being manually opened in 5 minutes or less with a trained crew of no more than 6 people. A manually over ride for opening the door shall be provided in the event of a power failure. All entrances/exits shall have the capability of being closed, have provisions for nighttime blackout, and prevent the intrusion of pests, insects, and indigenous crawling wildlife. Windows are not required. Table 3 lists the openings required for the XLDAHS.


Table 3. Exit/Entrance Requirements






BOCA 1996, Chapter 10, Use Group F-1



AGE Ports 6 18" 36"

Two on front face in the aircraft opening - approx. 50’ from centerline of shelter

Two on the back face - Approx. 50’ from centerline of shelter

One on each side – Approximately in the Center

Truck/Equipment –Located Opposite Aircraft Exit/Entrance


10 Ft

12 Ft



20 Ft

192 Ft


3.2.2 Structural Design . The XLDAHS shall meet the building code requirements of ANSI/ASCE 7-95, Minimum Design Loads for Buildings and Other Structures, for the climatic conditions listed in Table 4.

Table 4. XLDAHS Climatic Design Criteria



Wind Load (minimum)

110 mph

Max Wind Load - Severe Weather Disassembly i.e. Support Structure Only; Cladding Material and Liner Removed

155 mph Desired

Snow Load (minimum)

50 psf Ground Snow


5 in./hr with 30 minute duration

Blowing Sand and Dust (XLDAHS to remain operational under the listed conditions)

Blowing Dust with 20 mph winds

Blowing Sand with 55 mph winds


The following shall be used to define the wind loading on the XLDAHS according to ANSI/ASCE 7-95 Minimum Design Loads for Buildings and Other Structures:

1. Design wind speed = 110 mph.

2. Building Category III

3. Importance Factor (Wind Loads) = 1.15

4. Exposure Category = D

5. No wind tunnel data acceptable. Velocity pressure exposure coefficients, Kh and Kz,, must be taken from Table 6-3 of ASCE 7-95. All coefficients of pressure and force shall be taken from ASCE 7-95.

6. Kzt = 1.0

The following shall be used to define the snow loading on the XLDAHS according to ANSI/ASCE 7-95:

    1. Ground snow load = 50 lb/ft2
    2. Building Category = III
    3. Important Factor (Snow Load) I = 1.1
    4. Exposure Factor Ce = 1.0 (Partially Exposed Category C).
    5. Define building as an unheated structure for the thermal factor, Ct, in ASCE 7-95 Table 7-3, Ct = 1.2
    6. Determine Roof Slope Factor Cs for cold roofs.

The loads shall be calculated in accordance with ANSI/ASCE 7-95 Minimum Design Loads for Buildings and Other Structures. The structure shall not exceed the allowable stress (incorporating safety factors for buildings and similar type structures) as defined in the Aluminum Association’s Aluminum Design Manual, Specifications and Guidelines for Aluminum Structures, or the allowable stress (incorporating safety factors for buildings and similar type structures) as defined in the American Institute of Steel Construction’s Manual of Steel Construction, Allowable Stress Design for Steel Structures.

3.2.3 Anchoring. The shelter system shall be erectable on Asphalt Cement Concrete (ACC), or Portland Cement Concrete (PCC) pavement capable of supporting a B-2 aircraft. Contractor shall provide anchoring kits for each type of pavement. The anchors used must be standard, commercially available items, so that replacements will be readily available. The above ground portion of the anchors must be removable and damage to the pavement easily repaired so as not to impede the use of the pavement after the shelter is removed. The anchoring system shall withstand the environmental conditions listed in Table 4, XLDAHS Climatic Design Criteria, without degradation.

3.2.4 Safety Lanyard Support Structure. Maintenance personnel working on top of the aircraft require safety lanyards. A system for safely supporting these lines shall be included as part of the shelter structure. A typical fall protection system consists of an anchorage, lifeline, lanyard, deceleration device, and body harness. The contractor will be responsible for providing the anchorage only. The anchorage may be constructed from structural shapes or tensioned horizontal cables as long as the system meets the OSHA regulations of 29 CFR part 1926. The anchorage shall support a maximum of three personnel on each side of the aircraft at one time. Personnel are not allowed to cross the centerline of the B-2 aircraft. Therefore, two systems may be employed. Each system must provide continuous access from the wingtip to the centerline of the B-2 aircraft.

3.2.5 Erectability. The XLDAHS shall be erectable by a trained crew of no more than 15 and be fully functional in no more than 36 hours. All tools, equipment, heavy equipment, and apparatus required, and the quantity required to erect the XLDAHS shall be defined. Commercially available, simple, quick-disconnect type fasteners, hinges, and pins shall be utilized to the maximum practical extent without compromising safety. Erection time shall start with the system packed and located in the vicinity of the erection site. Erection time is for a team under ideal conditions. Ideal conditions are defined to be a no-wind to 5-mph wind, short sleeve environment. System erection time in winds from 6 mph to 15 mph shall not exceed two times the erection time under ideal conditions. System erection shall be possible while personnel are clothed in bulky winter gear or nuclear/biological/chemical Mission Oriented Protective Posture (MOPP) 2 gear under ideal conditions.

3.2.6 Severe Weather Partial Disassembly. Once installed, but without the cladding materials and liners in place, the XLDAHS shall withstand 155 mph winds without exceeding the allowable stress (incorporating safety factors for buildings and similar type structures) as defined in the Aluminum Association’s Aluminum Design Manual, Specifications and Guidelines for Aluminum Structures, or the allowable stress as defined in the American Institute of Steel Construction’s Manual of Steel Construction, Allowable Stress Design for Steel Structures. The 155-mph requirement shall be evaluated using ANSI/ASCE 7-95. The time requirement for severe weather skin surface (cladding materials and liners) disassembly shall not exceed 12 hours by a trained crew of no more than 15.

3.2.7 Wind, Rain, and Moisture Resistance. The XLDAHS shall be capable of withstanding a minimum steady wind of 110 miles per hour (See Table 4). The XLDAHS shall resist intrusion by rain under the same wind conditions without evidence of leakage.

3.3 Environmental Control System (ECS) Requirements. The XLDAHS shall have the ability to operate either with or without an ECS. Any required openings for the ECS shall have the ability to seal when the ECS is not used. The XLDAHS shelter, without ECS, shall have a minimum ventilation rate of 0.5 fresh air changes per hour based on the total volume of the shelter. All fresh air supply and exhaust must be arranged to prevent short circuiting in order to eliminate the possibility of bringing exhausted air back into the facility. Exhaust shall be arranged to remove air at floor level. Incoming fresh air shall be filtered for sand and dust.

3.3.1 Design Conditions. The shelter system (see paragraph 3.2) shall be able to operate in the climatic conditions shown in Table 5, XLDAHS Basic Environmental Performance Matrix and maintain the interior conditions of 65 to 85 degrees F @ 30 to 80 % Relative Humidity.


Table 5. XLDAHS Basic Environmental Performance Matrix



Outside Air Temperature/Humidity - Design conditions for XLDAHS

-65° F/ 100% RH (Desired)

-25° F/ 100% RH (Required)

+105° F/ 60% RH (Required)

+125° F/ 3% RH (Required)

Personnel Cooling Load - Based on 10 personnel performing light work

Sensible: 3,450 BTU/hr

Latent: 4,350 BTU/hr

Fresh Air

Minimum of 0.5 fresh air changes per hour.

Lighting Load (power consumption)

Based on lighting provided per Para. 3.4.5 of this document.

Solar Load

1,100 Watts/m2

Other Equipment Loads

10,000 Watts

Source: Military Standard 210C, 15 Apr 86

3.3.2 ECS Capabilities. The ECS system shall have the following capabilities. These capabilities facilitate the shelter’s function as a B-2 Aircraft Maintenance hangar. Ventilation. The ECS shall have a minimum ventilation rate of 0.5 fresh air changes per hour based on the total volume of the shelter. All fresh air supply and exhaust must be arranged to prevent short circuiting in order to eliminate the possibility of bringing exhausted air back into the facility. Exhaust shall be arranged to remove air at floor level. Aircraft Stabilization. When a B-2 aircraft is brought into the shelter system, it may have a temperature far higher or lower than that specified for the shelter. Due to the mass of the B-2 aircraft (350,000 lbs.), heating/cooling loads from convection and thermal radiation may far exceed the loads generated by environmental factors. The ECS shall include additional capacity to handle these loads. Thermal characteristics of the B-2 aircraft are shown in Table 6. The XLDAHS ECS system shall heat or cool a B-2 aircraft from a cold or heat soaked condition to a stabilized condition where the skin temperature is between 65 and 85 Degrees F. The stabilization shall be completed within 6 hours. Shelter interior temperature of 65 to 85 degrees @ 30 to 80% relative humidity requirements shall be maintained by the ECS for this mode. Supplemental fans to increase heat transfer between the aircraft and the shelter interior air may be utilized, if required.

Table 6. Thermal Characteristics of the B-2 Aircraft

Thermal Characteristic




350,000 lbs.


Surface Area

10,000 Sq. Ft


e, Emissivity


For Radiative Heat Transfer

Temperature of Aircraft



130 Deg F

-25 Deg F

-65 Deg F (Desired)

Heat Soaked Condition

Cold Soaked Condition

Thermal Capacitance

135,000 BTU/Deg F


Stabilization Requirement

6 Hours

Time allowed to heat or cool aircraft to between 65 and 85 Deg F from Heat Soaked or Cold Soaked Condition Filtration System. The ECS system shall include filtration for dust particle to prevent damage to internal ECS components.

3.4 Electrical Requirements: Electrical power will be furnished by the government at 4,160 volts, 50/60 Hz, ungrounded delta, from diesel powered prime power units (PPU). Each PPU consists of 2 Caterpillar 3456 engines mated to Caterpillar SR4B, 460 kW alternators. The PPU is trailer mounted and has a combined capacity of 920 kW. Each PPU has two, three phase feeder positions with 200-ampere vacuum interrupters on each feeder. Multiple PPUs can be paralleled for larger loads. All equipment selected by the contractor’s design shall be compatible with the PPUs.

3.4.1 Transformers. If a transformer is required, the transformer shall be sized and provided by the contractor and shall be equipped with 200 ampere bushing well inserts compatible with the standard 15 kV load break elbows. All primary voltage transformers furnished by the contractor shall be pad mounted, enclosed type, with provisions for cable entry and exit from the bottom of the device. The primary and secondary compartments shall be separated with a barrier and the primary cable connections shall be dead-front type with cable parking stands for each cable installed. The transformers shall have taps that are in 2.5% increments and consist of two taps above and below nominal voltage as a minimum. The tap changer control handle shall be external to the transformer tank. No Polychlorinated Biphenyl (PCB) insulating agents shall be allowed in any oil filled transformers.

3.4.2 Switch Gear. The switch gear shall be designed and rated for outdoor operation. All fuses and circuit breaker equipment protection devices shall be located as near as possible to the equipment being protected. All switch gear shall meet the requirements of the latest issue of the National Electrical Code (NEC). Switch gear shall be sized to adequately serve and protect the total load recommended for the environmental control system (if ECS is electrically powered) and the other ancillary load required, such as lighting and work tools and equipment.

3.4.3 Cabling. All cabling and wiring shall meet the requirements of the NEC and shall be sized for adequate current carrying capability. The voltage drop from source to load must not vary more than 5%. These cables shall be rated for direct burial, underground use. All electrical cables must be protected as much as possible from pedestrian traffic and cables in the path of any vehicular traffic must be mechanically protected from such traffic by the contractor.

3.4.4 Lighting. The shelter system shall have lighting that is capable of providing 100 foot-candles of illumination at the points indicated on the top surface of the B-2 Aircraft shown in Figure 1. The top of the B-2 Aircraft is approximately 17 feet above the floor. All other areas in the structure shall have illumination of 50 foot-candles at 4 feet above the floor. All lighting fixtures and associated wiring must be industrial grade and rated for wash down locations.


Figure 1. B-2 Shelter Lighting Requirement

3.4.5 Electrical Tools, Accessories, and Receptacles. The XLDAHS must provide electrical power distribution for the tools and equipment listed in Table 7.


Table 7 Electrical Load Requirement for Tools and Work Equipment





Power in kVA

# of


Total Pwr

in kVA








Fluorescent Floor Lamps







Bullard Pumps







LO or Structural Maint. ATACS







Vacuum Compressor

















All receptacles shall be located in an area that requires NFPA 70 Class 1, Division 2 wiring and all equipment shall be wired to that standard. Additionally all receptacles shall be watertight, suitable for wash-down of the structure without failure. There shall be four groups of receptacles installed either on structural members of the shelter or on a free standing fabricated panel that houses the entire group of receptacles. If these freestanding panels are used they shall be designed such that they will not tip over easily when the plugs are inserted or removed. These groups of receptacles shall be located on each end of the shelter approximately one half the distance from the front and back walls and one each panel located on either side of the back door approximately one half the distance from the back door to each end wall of the shelter.

Receptacle compatibility with existing equipment electrical plugs is required. See Table 8 for existing receptacles and numbers of receptacles required.

Table 8 Existing and Required Receptacles

Receptacle Description

Device Served

Compatible Receptacles Required

Receptacle-Hubbell Cat. # UGRO 20231, 20 Amp, 125 Volt, 60 Hz

Floor Lamps and Misc. Tools


Receptacle - Class L #MS90555C32412S

ECUs & Vacuum Compressor


Receptacle - Hubbell # CS 8269, 240 Volt, 60 Amp, 60 Hz, 1 Phase, 3 Wire, Twist Lock

Bullard Pumps & ATACS Equipment


Receptacle - # 2723 NEMA-

Compatible with 30 Amp, 250 Volt, 3

Phase, Twist Lock # 2721 NEMA 15-

30P Nylon Body Plug



3.4.6 Motor Starting. Large electric motor may require additional starting capability. Any equipment furnished for this purpose shall be compatible with the Air force prime power generating capabilities as stated in Paragraph 3.4.1.

3.4.7 Lightning Protection. The shelter system shall include a lightning protection system IAW the National Electrical Code and NFPA 780.

3.4.8 Electrical Grounding. The shelter system shall be grounded through the electrical power input cable back to the power source ground.


3.5 Environmental, Safety, and Occupational Health (ESOH)

      1. Compliance Requirements. The shelter system shall meet the ESOH requirements shown in Table 9.

Table 9. ESOH Compliance Requirements





Clean Air Act

Meet 40 CFR

Ensure Facility Can Comply

Report variances

Clean Water Act

Meet 40 CFR

Ensure Facility Can Comply

Report variances

Resource Conservation Reauthorization Act (RCRA)

Meet 40 CFR

Ensure Facility Can Comply

Report variances

Ozone Depleting Substances

No Class I ODS

no ODS desired

Current USAF policy prohibits Class I ODS

EPA top 17 Priority pollutants



Report variances

Occupational Safety and Health Act

Meet 29 CFR

Ensure Facility Can Comply

Report Variances

Sources: EPA, OSHA, and USAF Environmental Policy

3.5.2 Ventilation: The XLDAHS ventilation system shall be capable of satisfying all of the ESOH requirements listed in table 9.

3.5.3 Toxicity. The materials used in their cured state of the XLDAHS shall not cause skin irritations or other injury to personnel using or handling the material during transportation, operation, or maintenance of the system.

3.5.4 System Safety Requirements. The XLDAHS shall be safe to operate, store, transport and maintain throughout the life cycle of the system and not present a hazard to the aircraft or aircrews operating from or near the aircraft. The XLDAHS Design shall limit the hazards inherent to the design, construction, assembly and testing, and interfacing with ancillary electromechanical equipment. The contractor shall ensure all tasks associated with the transportation, erection, utilization, striking and reconstitution of the XLDAHS can be performed safely by all personnel. MIL-STD-882C, with emphasis on subsystem, system level, and operating/support hazard analyses, may be used as safety design guidance.

3.5.5 Human Performance/Human Engineering. The design shall place emphasis on simplicity of structural design for the purpose of quick system erection and striking. Parts shall be designed to minimize improper mounting and incorrect alignment. MIL-STD-1472D, with emphasis on ergonomic data may be used as guidance for the design of the system. Systems must not present undesirable or uncontrolled ergonomic hazards to personnel

3.6 Materials, Processes, and Parts. The XLDAHS design shall use best commercial practice as the benchmark to measure suitability of materials. The XLDAHS shall not create any hazards from special materials used in its construction. The selection of parts, materials, processes, protective treatments and finishes shall ensure that system performance is not impaired and safety is not compromised during use, storage, and service life. Protective coatings/treatments shall be used to reduce corrosion and deterioration in extremes of climate and environmental conditions. The contractor may use MIL-STD-210C, MIL-STD-808A, MIL-STD-810E, and
MIL-STD-889B as guidance.

3.6.1 Standardization. The shelter system shall have a standardized integration scheme to allow for standardized tools and repair parts, and to the maximum extent economically feasible, employ modularity, and interchangeability of components and parts. All XLDAHS components must be: simple to operate, store, and maintain; ruggedized for field use; portable; and reliable.

3.6.2 Corrosion Resistance. The shelter system shall be designed to resist corrosion and other environmental deterioration. Selection of materials, corrosion prevention techniques and design features shall be in accordance with best-established commercial practice. MIL-STD-889B may be used as guidance.

3.6.3 Fungi/Mildew Resistance. Materials that are nutrients for fungi or provide the environment for fungi growth shall not be utilized unless they are treated for fungus/mildew resistance.

3.6.4 Ice Formation. The shelter design shall not permit water accumulation in pockets, creases, fissures, or depressions, which could cause structural damage upon freezing. The operation of moving shelter components shall not be impaired by the formation of ice anywhere in the shelter system structure.

3.6.5 Color and Colorfastness. The shelter system exterior shall be colorfast. The exterior material of the shelter structure shall be available for procurement in the following colors: Camouflage green (color # 34094), desert tan (#33446), and arctic white (#37875). The interior color of the shelter shall be a light reflective color. Refer to FED-STD-595B for description of color numbers.

3.6.6 Weather Performance. The performance of the materials and subsystems of the shelter system shall not be affected by the climatic extremes outlined in this specification.

3.6.7 Tear Resistance. The XLDAHS material, seams and stitching shall be tear resistant.

3.6.8 Fire Protection. The XLDAHS shall meet the following requirements for fire protection. Structural Components. All structural components of the shelter shall be non-combustible – Uniform Building Code Standard 2-1 / ASTM Standard Method of Test E136-96. Fabric Membrane. Fabric membrane materials must be Flame-retardant – UBC Standard 31-1 / National Fire Protection Association Standard 701. Fabric membrane materials shall be have a flame spread less than 25, smoke development less than 450 and fuel contribution of 0 – ASTM Standard Method of Test E84-96.

3.6.9 Solar Radiation and Ultraviolet Effects. The shelter system shall be capable of withstanding up to 205 degrees F. Peak outer surface temperature for 4 hrs/day for one year continuous use with no permanent deformation, no delamination, nor loss of material strength and seals. The shelter system shall withstand worldwide ultraviolet effects for one-year continuous use with minimal degradation of system components.

3.6.10 Ruggedness. The XLDAHS system shall be capable of performing its operational function after being subjected to shocks and vibrations induced when transported by air; rail; sea; and when ground transported by forklift and truck over unimproved terrain. For forklift handling, the XLDAHS shall be capable of withstanding shock, vibration, and stresses of forklift movements, and except for minor forklift tines abrasions, no permanent damage shall occur. To ensure these requirements are met, the XLDAHS shall be subjected to and pass the International Safe Transit Association (ISTA) Export Testing, Procedure 2. Testing shall be conducted by an ISTA certified lab. Certification documentation, including a lab test report that tests have been accomplished, and passed, shall be generated.

3.6.11 Petroleum, Fuels, Oils, and Lubricants. The shelter materials, electric cables and other components shall be resistant to petroleum, engine oils, lubricants, hydraulic fluid, gasoline, Diesel fuel, JP-8, ammonia, and paint thinner.

3.7 Logistics and Readiness

3.7.1 Operational Availability. Operational Availability (Ao) is a component of reliability (Para 3.7.2) and maintainability (Para 3.7.3). Ao shall be greater than 98%.

Ao = Mean Time Between Maintenance (MTBM)

MTBM + Mean Down Time

3.7.2 Reliability. The XLDAHS shall withstand 20 erection/strike cycles within a 20-year storage life. The ECS shall withstand 20 set-up/take-down cycles within a 10-year storage life. The complete system is required to operate for 1 year under continuous use conditions with no critical failures. Mean Time Between Failure (MTBF) rate shall be 2,880 hours or greater and the Mean-Time Between Critical Failure (MTBCF) rate shall be 8,760 hours or more.

3.7.3 Maintainability. The integrated system shall require less than (<) 8 hours Mean-Time To Repair (MTTR) as a threshold and less than (< ) 4 hour as a goal. Use of existing DOD inventory support and test equipment is preferred.

3.7.4 Transportability. The XLDAHS shall be optimized for transport on C-141 aircraft in its packed configuration. Shipping weights and volumes of XLDAHS components should allow for the maximum utilization of available aircraft weight and volume limitations, thus minimizing the number of C-141 sorties (flights) required to transport the XLDAHS. See Annex A for additional information on the 463L Cargo System. For planning purposes, C-141 sortie requirements are based on the weight and volume criteria shown in Table 10: C-141 Sortie Planning Factors.

Table 10

C-141 Sortie Planning Factors



Maximum Payload

45,000 pounds

Main Cargo Compartment Length

90'-10" (pallet positions 1-12)

Aircraft Ramp

10'-11" (pallet position 13)

Maximum Pallet weights

Positions 1-12: 10,355 pounds

Position 13: 7,500 pounds

Maximum Pallet Heights

Positions 1&13: 76 inches

Positions 2-12: 96 inches

Maximum Axle Weights For Wheeled Equipment

Positions 1-4: 10,000 pounds

Positions 5-7: 20,000 pounds

Positions 8-12: 10,000 pounds

Position 13: 7,500 pounds

3.7.5 Ship/Store Containers. The XLDAHS shall include shipping and storage containers for the shelters and an integral case for the ECS to meet the following requirements:

3.7.6 Nameplates or Product Markings. The XLDAHS will be permanently marked with part number, date of manufacture, contract number, serial number, and manufacturers CAGE code as a minimum. The Shelter and ECS should be permanently "tagged" to allow for the annotation of the number of completed cycles within its 20 cycle life.

3.7.7 Interchangeability. The XLDAHS design should stress commonality. Components shall be interchangeable between systems and replaceable at the organizational on-equipment (field) level.

3.7.8 Maintenance. All components of the shelter system must be easily installed and maintained. Organic maintenance will be performed by personnel with minimal specialized training, using common tools. Routine maintenance, repair and inspection tasks should be able to be performed by personnel wearing cold weather clothing and/or chemical warfare ensemble (MOPP 2). Levels of Maintenance. The integrated system is anticipated to be maintainable at three levels of organic maintenance: organizational, intermediate, and depot. The user will be responsible for any minor maintenance, servicing and repair utilizing the Contractor Technical Manuals (CTM) and available parts. The Civil Engineer Heating, Ventilation, and Air Conditioning (HVAC) and Fabrication Shops will be responsible for any maintenance, servicing, and repair beyond the capabilities of the user utilizing the CTMs and the spares repair kits. Maintenance and Repair Cycles. The requirement for scheduled/periodic maintenance and inspections at the system level shall be kept to an absolute minimum. This system could be placed in storage in War Readiness Materials (WRM) facilities or be stored outdoors, covered storage for up to 20 years. This storage requirement should not place excessive (>16 man-hours) or frequent (<180 days) scheduled and/or periodic maintenance or inspections requirements on the users. Support/Test Equipment. This system shall not drive the requirement for any peculiar support or test equipment. If tools, test measurement and diagnostic equipment (TMDE) and/or support equipment (SE) are required the DOD supply inventory of existing tools must be used. A spares/repair kit for on-equipment (field), level repair of both the shelter and ECS is required. This kit should allow field level repair of the Shelter System with no system degradation. The spares/repair kits for the shelter and ECS shall contain adequate spare and/or repair parts to allow for removal, replacement and repair of modules, components and materials at the organization level to support deployments of at least 60 days. The shelter spares/repair kit shall be packaged with the shelter ship/store container. A separately packed spare/repair kit shall be provided for the ECS. The number of kits required to support a group of systems is to be determined by the contractor based on contractual reliability, availability, and maintainability requirements.

3.7.9 Supply. The XLDAHS shall utilize standard commercial parts. A spares/repair kit will be utilized to repair fielded systems. Once the parts are consumed from these kits, an additional supply of parts must be available to the user throughout the system life-cycle. NOTE: The specific supply support concept will be determined after contract award.

3.7.10 Personnel and Training. The XLDAHS shall require minimum training and personnel to utilize and maintain. Shelter Support Requirement. The shelter shall be capable of being broken-out and erected, disassembled, reconstituted, and maintained utilizing the contractor-developed commercial technical manuals (CTM). The shelter shall be repairable (minor) at the organizational on-equipment (field) level by unskilled personnel utilizing the provided CTMs and spares/repair kit. The shelter shall be repairable at the organizational intermediate back-shop level by no more than 2 skilled specialists utilizing the CTMs, the spares/repair kit and any additional parts required to return the system to a fully serviceable condition. ECS Support Requirements. The ECS shall be capable of being connected and/or disconnected to the shelter to create the integrated system utilizing the contractor developed CTMs and common tools. The ECS should be capable of being serviced (i.e., clean and replace filters and replace fuses) at the organization on-equipment (field) level by unskilled personnel utilizing the provided CTMs and spares/repair kit. The ECS shall be repairable at the intermediate back-shop level by no more than 2 skilled specialists utilizing the CTMs, the spares/repair kit and any additional parts required to return the system to a fully serviceable condition. Training. HQ AETC involvement in a formal, Type I Training Requirement is TBD and will be determined after contract award . Contractor training shall be conducted to enable the initial cadre of test, acquisition, and user personnel to perform system break-out, erection, strike, reconstitution, and operation and maintenance procedures for the integrated system during the initial period of operation and test. The initial cadre of user personnel will be required to utilize this training to establish any combination of unit level training and/or on-the-job training (OJT) programs to meet their life-cycle training requirements. An additional training requirement exists for "fast take down" training. In case of severe weather, the shelter is required to be made safe by NMT 15 people in NMT 12 hours.

3.7.11 Reconstitution. The XLDAHS shall be easily reconstituted (disassembled, cleaned/decontaminated, and repackaged into shipping/storage containers for transport ). The time for reconstitution shall not exceed 48 hours by a trained crew of no more than 15 working 12 hours per day. All XLDAHS interior surfaces shall be capable of being washed down and wiped clean with detergents and water, without causing any damage or deterioration. This requirement includes all the electrical equipment such as lighting, distribution, and convenience outlets. All electrical equipment shall be waterproof and rated for wash down. The structure will be washed down with a Trisodium Phosphate (TSP) solution made from 80% TSP powder diluted to between 1% and 2% in water.

3.7.12 Packaging, Handling, Shipping, and Transportation (PHS&T). Best commercial PHS&T practices are required when delivering production units to the government.

3.7.13 Government-Furnished Property (GFP). No GFP is anticipated.

4.0 Qualification Tests and Certification. The methods that shall be used to verify that the requirements stated in this System Performance Specification have been met include inspection, certification, demonstration, testing, modeling, simulation, and analysis.

5.0 COST. The shelter system shall have low acquisition, life cycle, and supportability costs. This is a "BEST VALUE" acquisition



The 463L system encompasses all phases of cargo loading, including material-handling equipment, cargo-loading platforms, restraint equipment, and in-aircraft systems. The 463L system is the USAF standard for moving concentrated cargo to be air landed. It comprises the following major components:

•Dual-rail system. The dual-rail system is installed in all airlift or 463L-capable military aircraft. This system consists of rows of rollers that allow the palletized cargo to easily move into the aircraft. Many of these rollers are stowable to convert the cargo deck to a flat, clear loading surface for wheeled or tracked cargo. The side rails guide the pallets into the aircraft and provide lateral and vertical restraint. These rails are equipped with detent locks that hold the pallet securely in place once inside the aircraft. The locks also prevent the forward and aft movement of pallets during flight. Cargo compartment floors also contain a series of tie-down fittings for securing wheeled or tracked cargo with chains.

•463L pallet. The 463L pallet is made of corrosion-resistant aluminum with a soft wood core and is framed on all sides by aluminum rails. The rails have 22 attached tie-down rings with six rings on each long side and five rings on each short side. Each ring has a 7,500-pound restraint capacity. The rails also have indents (notches) which are designed to accept the detent locks located on numerous types of material-handling equipment on all airlift-capable aircraft. The overall dimensions of the 463L pallet are 88 inches long by 108 inches wide by 2-1/4 inches thick. The usable dimensions of the surface area are 84 inches wide by 104 inches long. This allows two inches around the periphery of the pallet to attach straps, nets, or other restraint devices. An empty pallet weighs 290 pounds (355 pounds with nets) and has a maximum load capacity of 10,000 pounds. Two or more pallets can be connected together for movement of cargo that exceeds the dimensions or weight limitations of a single pallet.

•463L pallet nets. There are three nets to a set: one top net (yellow) and two side nets (green). The side nets attach to the rings of the 463L pallet. The top net attaches by hooks to the rings on the side nets. The nets have multiple adjustment points and can be tightened to conform to loads of almost any shape. A complete set of 463L nets pro vides adequate restraint for a maximum of 10,000 pounds when properly attached to a 463L pallet. A complete set of nets weighs 65 pounds.



•Other restraint devices. 10,000 and 25,000 pound (capacity) chains and locking devices are available to restrain large or heavy items such as containers, vehicles or tracked equipment. 5,000 pound straps are available for individual item restraint or to supplement 463L nets.

•Specialized 463L compatible containers with their own base or which incorporate an integral pallet base are available.

•Wheeled vehicles may be loaded directly on the cargo compartment floor and restrained with 10,000 and/or 25,000 pound capacity chains.