U.S. Department of Transportation Federal Aviation Administration Advisory Circular Subject: Aircraft Secondary Barriers and Alternate Flightdeck Security Procedures Date: 6/1/23 AC No: 120-110A Initiated by: AFS-200 Change:
1 PURPOSE OF THIS ADVISORY CIRCULAR (AC). This AC provides an acceptable means, but not the only means, to achieve effective protection of the flightdeck as required by Title 14 of the Code of Federal Regulations (14 CFR) part 121, § 121.584 by implementing a secondary barrier. The contents of this document do not have the force and effect of law and are not meant to bind the public in any way, and the document is intended only to provide information to the public regarding existing requirements under the law or agency policies.
2 AUDIENCE. The guidance in th is AC applies to air carriers, manufacturers, installers, and all Flight Standards (FS) offices to convey effective methods to best protect the flightdeck during door transition.
3 WHERE YOU CAN FIND THIS AC. You can find this AC on the Federal Aviation Administration’s (FAA) website at https://www.faa.gov/regulations_policies/advisory_cir culars and the Dynamic Regulatory System (DRS) at https://drs.faa.gov.
4 WHAT THIS AC CANCELS. AC 120-110, Aircraft Secondary Barriers and Alternate Flight Deck Security Procedures, dated April 14, 2015, is canceled.
5 RELATED 14 CFR SECTIONS.
5.1 Part 25.
• Section 25.772, Pilot Compartment Doors.
• Section 25.795, Security Considerations.
5.2 Part 121.
• Section 121.135, Manual Contents.
• Section 121.313, Miscellaneous Equipment.
• Section 121.547, Admission to Flig ht Deck.
• Section 121.584, Requirement to View the Area Outside the Flightdeck Door.
• Section 121.587, Closing and Locking of Fligh tcrew Compartment Door.
2 6 RELATED READING MATERIAL. The following documents are related to the guidance in this AC. The latest version of each document at the time of publication of this AC is identified below. If any document is revised after publication of this AC, refer to the latest version on DRS.
• FAA Order 8900.1, Volume 3, Chapter 2, Section 1, Exemptions, Deviations, Waivers, and Authorizations, Subparagraph 3-47B, Certificate Holders’ Procedures.
• AC 25.795-10, Installation Requirements of Physical Secondary Barriers for Transport Category Airplanes.
7 DEFINITIONS. For this AC, the following definitions apply:
7.1 Human Barrier(s). The use of cabin or flight crew as part of the improvised non-installed secondary barrier (INSB).
7.2 Improvised Non-Installed Secondary Barrier (INSB). A secondary barrier system that accounts for the use of crew and/or a galley cart to protect the flightdeck during a door transition.
7.3 Installed Physical Secondary Barrier (IPSB). A barrier that is installed to delay unauthorized access to the flightdeck when the flightdeck door is opened.
8 BACKGROUND.
8.1 On long flights, as a matter of necessity, flightcrew members must open the flightdeck door to access lavatory facilities, to transfer meals to flight crewmembers, or to switch crew positions for crew rest purposes. The opening and closing of the flightdeck door (referred to as “door transition”) reduces the protective anti-intrusion/anti-penetration benefits of the reinforced door. If flightcrew members do not properly use established procedures and/or equipment during this door transition, the flightdeck is vulnerable.
8.2 To date, passenger air carriers have employed three basic methods to support security of the flightdeck when opening the flightdeck door during flight. Two of the methods are INSBs. The first INSB method is a human barrier, which uses a crewmember(s) to monitor the area in front of the flightdeck door and block access to the flightdeck during the door transition. The second INSB method employs a combination of procedures using crewmembers to monitor the area in front of the flightdeck door and aircraft equipment, such as galley carts, to block access to the flightdeck during the door transition. A third method is to block access to the flightdeck through the use of an IPSB.
8.3 The FAA Reauthorization Act of 2018 required the installation of IPS Bs on newly manufactured passenger aircraft operating under part 121. The FAA adopted amendments 25-150 and 121-389, with § 121.313(l) requiring the installation of IPSBs and § 121.584(a)(3) requiring the use of them in flight when opening the flightdeck door.
This AC outlines acceptable means of compliance with § 121.584, regardless of whether IPSBs are required or not.
3 9 ACCEPTABLE METHODS OF COMPLIANCE WITH § 121.584.
9.1 Aircraft Not Required to Have an IPSB Installed in Accordance With § 121.313(l).
9.1.1 Determine the method of secondary flightdeck security you intend to use.
1. Use of IPSB. IPSB meets the requirements of § 25.795(a)(4), or has supplemental procedures in place as an equivalent level of safety.
2. Use of a galley cart and crewmember as an INSB.
3. Use of a human barrier as an INSB.
9.1.2 Establish procedures for the secondary flightdeck security method selected, to include required training of crewmembers.
9.1.3 Present the method and procedures to your FAA Principal Operations Inspector (POI) for approval.
9.2 Aircraft Required to Have an IPSB Installed in Accordance With § 121.313(l).
9.2.1 Use of an IPSB that meets the requirements of § 25.795(a)(4).
9.2.2 Establish procedures of secondary flightdeck security using the IPSB, to include required training of crewmembers.
9.2.3 Present the procedures to your FAA POI for approval.
9.3 Additional Crewmember Procedures and Training for All Aircraft.
9.3.1 Operator procedures generally require the flightdeck door to be opened for only a brief amount of time, in accordance with industry best practices.
9.3.2 Include crewmember procedures and training where an INSB must be used in the event an IPSB malfunction.
9.3.3 Include crewmember procedures and training where an INSB must be used in the event an IPSB is inoperative and the carrier has approved minimum equipment list (MEL) relief.
9.3.4 For air carriers that have a fleet in which some aircraft are required to have IPSBs installed and some are not, include crewmember procedures and training for IPSBs and INSBs.
9.4 Non-U.S. Air Carriers. This AC is not applicable to non-U.S. air carriers.
4 10 AC FEEDBACK FORM. For your convenience, the AC Feedback Form is the last page of this AC. Note any deficiencies found, clarifications needed, or suggested improvements regarding the contents of this AC on the Feedback Form.
Wesl ey L. Mooty Acting Deputy Executive Director, Flight Standards Service
Advisory Circular Feedback Form If you find an error in this AC, have recommendations for improving it, or have suggestions for new items/subjects to be added, you may let us know by contacting the Air Transportation Division (AFS 200) at 9-AWA-AVS-AFS-200-Air-Transportation-Division@faa.gov or the Flight Standards Directives Management Officer at 9-AWA-AFB-120-Directives@faa.gov.
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