Secondary Barriers on Commercial Aircraft

The downing of four commercial airplanes and loss of nearly 3,000 lives on 9/11 was due, in part, to inadequate protection of the aircraft flight deck. Shortly after 9/11, Congress and the FAA required the installation of hardened flight deck doors on most commercial airline aircraft as one of many new layers of security. The hardened flight deck doors are an important improvement to security, but they are not a complete solution to preventing unauthorized individuals from entering the flight deck. The flight deck door must be opened during flight to provide for pilots’ biological needs and for operational requirements related to safety.

As events have demonstrated, Americans still remain vulnerable to terrorist attacks. There have been at least 52 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.

Since 2003, two major airlines have voluntarily installed a lightweight, inexpensive wire mesh, called a flight deck secondary barrier, on hundreds of their aircraft, which is permanently mounted between the flight deck door and the cabin. Boeing and Airbus offer the secondary barrier as equipment on new aircraft. Installation of retrofitted secondary barriers on aircraft already in the fleet represents a minimal cost, as they can be added at a cost of approximately $5,000 per aircraft or even less.

During the 114th Congress, legislation was introduced in both the House and Senate (i.e., H.R. 911 and S. 911) to address this issue by mandating secondary barriers for all commercial passenger operations. A version of these bills, which mandated secondary barriers on all new aircraft, was included in both the FAA reauthorization bill that passed the full Senate and the House counterpart that passed out of committee. (Note: The House never voted on a full FAA reauthorization on the floor during the 114th Congress.)


  • Congress should include a secondary barrier requirement in any FAA reauthorization legislation that is considered in the 115th Congress.
  • The FAA should require secondary barriers on passenger aircraft.

Download the Secondary Barriers White Paper
Download ALPA's Position Paper