Product Area: Conveyance Protection

Conveyance Protection Overview

The public relies on a layered, system-of-systems approach for national security, in which the first line of defense is always preemptive threat neutralization based on reliable intelligence. To address those threats not successfully neutralized at some earlier stage, The Transportation Security Administration (TSA) carries out routine screening of people and inspection of goods to prevent explosive devices and other dangerous items from getting aboard airplanes or other commercial conveyances. Unfortunately, terrorists are patient, creative, and persistent in their efforts to identify and exploit the slightest vulnerabilities of these screening systems. A final line of defense is to mitigate the effects of an assault on conveyances.

The Transportation Security Laboratory's (TSL) Conveyance Protection group focuses on projects that identify, assess, and mitigate vulnerabilities in commercial transportation networks. Their primary focus is to identify vulnerabilities and develop blast mitigation technologies that contain explosions, mitigate blast effects, and prevent catastrophic structural or critical systems failure.

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Vulnerability Assessment

The Conveyance Protection team works to determine the vulnerability of aircraft, vehicles, and vessels, subject to internal explosive blasts. Though the primary focus is on aircraft passenger and cargo-hold areas, work has begun on the assessment of hazmat rail tank cars. Aircraft vulnerability assessments may be used to develop, validate and refine explosive detection standards for checked baggage, checkpoint and air cargo, while rail tank car vulnerability assessments may be used to determine the potential consequences of a massive release of chlorine gas in an urban environment.

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Blast Effects Mitigation

The Transportation Security Laboratory's (TSL) Conveyance Protection group supports the development of blast mitigation technologies that contain explosions, mitigate blast effects, and prevent catastrophic structural or critical systems failure. Blast mitigation is focused on applications where other defensive methodologies further up the chain of events are not possible or not sufficiently effective (for example, the detection of very small threat masses). The implementation costs of proposed technologies are assessed prior to development and then re-assessed more formally as the technologies mature.

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Products

The Conveyance Protection group's products include:

1. Vulnerability Assessments: For use in setting explosive detection system (EDS) requirements or specifying performance requirements for blast mitigating technologies.
2. Hardened Containers and Appliances for Aircraft: Hardening technologies that do not require significant or unique aircraft modification. Hardened unit load device (ULD), hardened narrow-body loaders.
3. Blast Resistant Liners and Structural Systems for Aircraft Retrofit: Blast resistant fuselage liners and hardened overhead bins.
4. Vulnerability Assessment Tools: Tools to assist security organization in assessing the vulnerability of aircraft to emerging threat scenarios.
5. Blast Mitigating Techniques: Least risk bomb location procedures and safe breach design modifications.
   

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Results

Vulnerability Assessments. Since 1992, the TSL has conducted approximately 200 explosive tests on numerous retired commercial aircraft, in both passenger cabin and cargo hold areas under pressurized conditions (to simulate aircraft cruise altitude conditions) as well as unpressurized conditions (supplemented with analysis to predict lethality). The data from these tests are used to determine if explosives detection standards are adequate.

Characterization of Blast Effects. Working with industry partners, experts on the Conveyance Protection team have developed BlastDam, a semi-empirical computer simulation of blast effects on aircraft that uses first principals and equivalency data to produce assessments of aircraft vulnerability to a wide range of threat scenarios. BlastDam includes recently improved estimates of explosive characteristics and structural response parameters (including mach stem effects), which allow for parametric assessment and sensitivity studies for various threat scenarios.

Blast Effects Mitigation. Explosive mitigation concepts investigated to date include hardened containers, commonly known as hardened Unit Load Devices (ULD’s), explosive resistant aircraft passenger cabin and cargo hold liners, hardened overhead stowage bins and validation of Least Risk Bomb Locations (LRBL) procedures.

TSL has successfully developed and tested two generations of hardened ULDs. The second generation container weighs 65 pounds less than its predecessor and only about 100 pounds more than a conventional (non-hardened) ULD. The Conveyance Protection group is also working on a new generation of containers which are designed to be substantially lighter and less expensive. Because ULD’s (hardened or conventional) are limited to use in the cargo hold of wide-body aircraft, the Conveyance Protection team has also been developing aircraft-integral hardening technology for overhead bins (including liners and integrally hardened bins) and blast resistant fuselage liners for both the cargo hold and passenger cabin.

In 2001 the TSL developed a Threat Containment Unit (TCU) allowing safe storage and transport of certain explosive threats contained in passenger baggage. Suspect baggage identified by conventional Explosive Detection Systems as having less than 5 pounds of explosive can be placed in the TCU for safe removal to a disposal area. The TCU was designed to fully contain the effects of an explosive detonation in the event that an Improvised Explosive Device in the EDS identified threat bag detonates prior to being removed by Law Enforcement and Explosive Ordnance Disposal teams.

TSL’s Conveyance Protection group have conducted extensive explosive mitigation tests to support these efforts, including tests on both narrow and wide body aircraft, in passenger cabins and cargo holds. In addition, more than 300 associated tests have been conducted to collect supporting data, including tests to determine the suppressive and equivalence properties of passenger luggage and air cargo contents on explosive effects.

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