Secondary Barriers: A necessary security element on passenger aircraft

In 2001, Congress mandated reinforced flight deck doors on airliners following the attacks of 9/11. However, practical experience using these doors soon revealed a critical vulnerability—the reinforced door must be periodically opened during flight for pilots’ operational and physiological needs, which means they may be compromised by one or more terrorists who could rush the flight deck. To address this unintended security lapse, a secondary barrier was developed by airlines for use whenever the cockpit door is open during flight.

Secondary barriers are lightweight, wire-mesh, retractable locking screens that install between the flight deck door and cabin to give the crew time to open and shut the fortified flight deck door before a potential intruder has time to compromise security. Secondary barriers are inexpensive to install, costing approximately $5,000 to $12,000 per aircraft. Industry studies have found that they are a safe, effective way to add a layer of defense to the cockpit at a modest cost. Voluntary airline industry movement toward adopting secondary barriers began in 2003, but commitment to deploying these devices has since waned significantly.

As events have demonstrated, Americans still remain vulnerable to terrorist attacks. There have been at least 51 hijacking attempts around the world since 9/11. The U.S. government has repeatedly and recently confirmed that aviation, in particular, is still a target of radical terrorists and the threat of hijackings is real.


Flight Plan

Congress should enact legislation that would require that all passenger aircraft be equipped with a secondary barrier as a necessary layer of security. Bills have been introduced in the House and Senate (H.R. 911/S. 911) to require secondary barriers on aircraft.


Download the Secondary Barriers White Paper
Download ALPA's Comprehensive "Flight Plan"