DHS Conducting 'Least-Risk' Explosives Tests On Commercial Jets

By John Croft john.croft@aviationweek.com
Source: AWIN First
June 07, 2013

The Department of Homeland Security (DHS) is assembling a variety of “pressurizable” commercial airliner fuselages to be used for live-fire testing at the U.S. Army’s Aberdeen Test Center in northern Maryland. The work is part of a long-running Army and DHS program to study cabin locations or designs that will yield the least damage if a bomb found onboard an aircraft detonates.

Along with a fully assembled DC-9, there are six full fuselages in place at the southern end of the Phillips Airfield on the Army base, including a Boeing 737 in US Airways livery, a Bombardier CRJ, two Embraer ERJs, a DC-9-type fuselage, possibly a Boeing 717, and one other single-aisle aircraft, likely a 737. The airframes, based on aerial pictures taken by Aviation Week, do not show obvious signs of blast damage.

DHS confirms that it is conducting the least risk bomb location (LRBL) testing at Aberdeen as part of an interagency agreement with the Army, but can give no further details.

At least one of the Embraer ERJs is likely linked to a 2012 Army request to buy an Embraer ERJ-145 “solely for destructive purposes.” In the public documents at the time, the Army noted that “distinctive paint schemes or logos” on the exterior of the aircraft would have to be removed before testing “to eliminate any public recognition that the aircraft was previously owned or operated.”

By FAA regulations finalized in 2008, commercial aircraft holding more than 60 passengers or weighing more than 100,000 lb. must have a designated LRBL, a location “where a bomb or other explosive device could be placed to best protect flight-critical structures or systems from damage in case of detonation.”

While the LRBL for legacy aircraft may not be optimum, the intent of the rulemaking was to get airframers to begin including provisions for such a location into the aircraft early in the design phase. “Design considerations may include specially sized areas or pressure relief panels in the cabin structure where a suspect device should be placed by crew members,” the FAA says in a 2008 Advisory Circular that provides guidance to help manufacturers meet the intent of the LRBL rule.

The FAA says use of the LRBL procedures, which began with voluntary participation by airframers around 1972, have been shown to “significantly decrease the effects of an explosion in the passenger cabins of large commercial airplanes.” Compliance with the rule requires airframers to include the “amplifying effects” of the pressure differential between a pressurized cabin and the atmospheric pressure at cruise altitude, the worst-case scenario for bomb blast. The rule, however, does not require airframers to verify the LRBL selection by test, which is where the DHS activities come into play.

Army contract announcements reveal that an LRBL test is planned for a pressurized DC-9 “or equivalent” fuselage as part of a program called Army and DHS Scenario-Based Security/Threat and Mitigation Assessment of commercial aircraft LRBL. An August 2012 contract award to Boeing, “the sole manufacturer of the DC-9 aircraft being tested,” calls for the airframer to provide technical support during the planning, execution and post-test analysis of two “live-fire” LRBL explosive tests at Aberdeen through August 2013. In 2006, the Army requested to have two 737 and two Airbus aircraft sections delivered to Aberdeen for reasons not stated publicly in the documents.

Many other tests appear to be on the agenda at Aberdeen, based on the number of fuselages already at the airport and solicitations for additional aircraft.


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